LIAISON BRAHMS PCT II GEN, LIAISON Control BRAHMS PCT II GEN, LIAISON BRAHMS PCT II GEN Verifiers
Device Facts
| Record ID | K173683 |
|---|---|
| Device Name | LIAISON BRAHMS PCT II GEN, LIAISON Control BRAHMS PCT II GEN, LIAISON BRAHMS PCT II GEN Verifiers |
| Applicant | DiaSorin, Inc. |
| Product Code | PRI · Microbiology |
| Decision Date | Feb 27, 2018 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 866.3215 |
| Device Class | Class 2 |
Indications for Use
LIAISON® B.R.A.H.M.S PCT® II GEN assay uses chemiluminescence immunoassay (CLIA) technology for the in vitro quantitative determination of Procalcitonin in human serum and lithium heparin plasma specimens. Used in conjunction with other laboratory findings and clinical assessments, LIAISON® B.R.A.H.M.S.PCT® II GEN is intended for use as follows: - to aid in the risk assessment of critically ill patients on their first day of ICU admission for progression to severe sepsis and septic shock, - to aid in assessing the cumulative 28-day risk of all-cause mortality for patients diagnosed with severe sepsic shock in the ICU or when obtained in the emergency department or other medical wards prior to ICU admission, using a change in PCT level over time, - to aid in decision making on antibiotic therapy for patients with suspected or confirmed lower respiratory tract infections (LRT) defined as community-acquired pneumonia (CAP), acute bronchitis, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) - in an inpatient setting or an emergency department, - to aid in decision making on antibiotic discontinuation for patients with suspected or confirmed sepsis. The LIAISON® Control B.R.A.H.M.S PCT® II GEN (level 1 and level 2) are intended for use as assayed quality control samples to monitor the performance and reliability of the LIAISON® BRAHMS PCT® II GEN assay. The performance characteristics of LIAISON® BRAHMS PCT® II GEN controls have not been established with any other assay or instrument platform different from the LIAISON® Analyzer. The LIAISON® B.R.A.H.M.S PCT® II GEN Verifiers (four levels) are assayed quality control materials intended in the quantitative verification of calibration and reportable range of the LIAISON® BRAHMS PCT® II GEN assay. The performance characteristics of LIAISON® BRAHMS PCT® II GEN calibration verifiers have not been established in connection with any other assay or instrument platforms different from the LIAISON® Analyzer.
Device Story
LIAISON B.R.A.H.M.S PCT II GEN is an automated chemiluminescence immunoassay (CLIA) for quantitative Procalcitonin (PCT) measurement in human serum or lithium heparin plasma. Device operates on LIAISON Analyzer; utilizes sandwich immunoassay principle with magnetic particles coated with anti-katacalcin monoclonal antibodies and isoluminol-labeled anti-procalcitonin monoclonal antibodies. Analyzer measures flash chemiluminescence via photomultiplier; output is Relative Light Units (RLU) converted to PCT concentration. Used in clinical laboratories/hospitals; operated by trained laboratory personnel. Output aids clinicians in sepsis risk stratification, mortality assessment, and antibiotic stewardship (initiation/discontinuation). Benefits include objective biomarker data to guide critical care and antibiotic management.
Clinical Evidence
Bench testing only. Performance validated via precision (20-day study, %CV 5.5-17.1%), reproducibility (5-day study, %CV 4.8-16.8%), linearity (0.05-100 ng/mL), and method comparison against predicate (n=264, Passing/Bablok y=1.03x+0.06). Analytical specificity, interference (endogenous/exogenous), and stability studies confirm performance. No clinical prospective trials conducted for this submission; relies on analytical equivalence to predicate.
Technological Characteristics
Sandwich chemiluminescence immunoassay. Solid phase: magnetic particles coated with anti-katacalcin mouse monoclonal antibody. Conjugate: anti-calcitonin rat monoclonal antibody labeled with isoluminol derivative. Energy source: flash chemiluminescence. Form factor: Reagent Integral for LIAISON Analyzer. Connectivity: standalone analyzer. Sterilization: N/A (reagents). Software: embedded firmware on LIAISON Analyzer.
Indications for Use
Indicated for critically ill patients (ICU admission) for sepsis/septic shock risk assessment; patients with severe sepsis/septic shock for 28-day mortality risk assessment; patients with suspected/confirmed LRTI (CAP, acute bronchitis, AECOPD) for antibiotic therapy decision-making; and patients with suspected/confirmed sepsis for antibiotic discontinuation. Not indicated for patients <17 years, pregnant women, or immunocompromised individuals.
Regulatory Classification
Identification
A device to detect and measure non-microbial analyte(s) in human clinical specimens to aid in assessment of patients with suspected sepsis is identified as an in vitro device intended for the detection and qualitative and/or quantitative measurement of one or more non-microbial analytes in human clinical specimens to aid in the assessment of patients with suspected sepsis when used in conjunction with clinical signs and symptoms and other clinical and laboratory findings.
Special Controls
A device to detect and measure non-microbial analyte(s) in human clinical specimens to aid in assessment of patients with suspected sepsis must comply with the following special controls:
*Classification.* Class II (special controls). The special controls for this device are:(1) Premarket notification submissions must include the device's detailed Indications for Use statement describing what the device detects and measures, the results provided to the user, whether the measure is qualitative and/or quantitative, the clinical indications for which the test is to be used, and the specific population(s) for which the device use is intended. (2) Premarket notification submissions must include detailed documentation of the device description, including (as applicable), all device components, software, ancillary reagents required but not provided, explanation of the device principle and methodology, and for molecular devices include detailed documentation of the primer/probe sequence, design, and rationale for sequence selection. (3) Premarket notification submissions must include detailed documentation of applicable analytical studies, such as, analytical sensitivity (Limit of Detection, Limit of Blank, and Limit of Quantitation), precision, reproducibility, analytical measuring range, interference, cross-reactivity, and specimen stability. (4) Premarket notification submissions must include detailed documentation of a prospective clinical study or, if appropriate, results from an equivalent sample set. This detailed documentation must include the following information: (i) Results must demonstrate adequate device performance relative to a well-accepted comparator. (ii) Clinical sample results must demonstrate consistency of device output throughout the device measuring range likely to be encountered in the Intended Use population. (iii) Clinical study documentation must include the original study protocol (including predefined statistical analysis plan), study report documenting support for the Indications for Use(s), and results of all statistical analyses. (5) Premarket notification submissions must include evaluation of the level of the non-microbial analyte in asymptomatic patients with demographic characteristics ( *e.g.,* age, racial, ethnic, and gender distribution) similar to the Intended Use population.(6) As part of the risk management activities performed under 21 CFR 820.10(c) design and development, you must document an appropriate end user device training program that will be offered as part of your efforts to mitigate the risk of failure to correctly operate the instrument. (7) A detailed explanation of the interpretation of results and acceptance criteria must be included in the device's 21 CFR 809.10(b)(9) compliant labeling, and a detailed explanation of the interpretation of the limitations of the samples ( *e.g.,* collected on day of diagnosis) must be included in the device's 21 CFR 809.10(b)(10) compliant labeling.
Predicate Devices
- VIDAS® B-R-A-H·M·S PCT™ (K162827)
Reference Devices
- LIAISON® XL 1,25 Dihydroxyvitamin D Calibration Verifiers (K141463)
Related Devices
- K172713 — Lumipulse G BRAHMS PCT Immunoreaction Cartridges, Lumipulse G BRAHMS PCT Calibrators set · Fujirebio Diagnostics,Inc. · Dec 10, 2017
- K181002 — Atellica IM BRAHMS Procalcitonin (PCT) · Siemens Healthcare Diagnostics, Inc. · Jul 16, 2018
- K170652 — ARCHITECT B.R.A.H.M.S PCT, ARCHITECT B.R.A.H.M.S PCT Calibrators, ARCHITECT B.R.A.H.M.S PCT Controls · Fisher Diagnostics · Jun 1, 2017
- K040887 — B-R-A-H-M-S PCT LIA · Brahms Aktiengesellschaft · Jan 7, 2005
Submission Summary (Full Text)
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
A. 510(k) Number:
K173683
B. Purpose for Submission:
To obtain a substantial equivalence determination for the LIAISON BRAHMS PCT II GEN assay, LIAISON Control BRAHMS PCT II GEN and LIAISON BRAHMS PCT II GEN Verifiers.
C. Measurand:
Procalcitonin (PCT)
D. Type of Test:
Quantitative, Chemiluminescence Immunoassay
E. Applicant:
DiaSorin Inc.
F. Proprietary and Established Names:
LIAISON BRAHMS PCT II GEN
LIAISON Control BRAHMS PCT II GEN
LIAISON BRAHMS PCT II GEN Verifiers
G. Regulatory Information:
1. Regulation section:
21 CFR 866.3215; Device to detect and measure non-microbial analyte(s) in human clinical specimens to aid in assessment of patients with suspected sepsis
2. Classification:
Class II (Special Controls)
3. Product codes:
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LIAISON BRAHMS PCT II GEN: PMT
LIAISON Control BRAHMS PCT II GEN: NTM
LIAISON BRAHMS PCT II GEN Verifiers: JJX
4. Panel:
83 - (Microbiology)
## H. Intended Use:
1. Intended Use:
LIAISON BRAHMS PCT II GEN assay uses chemiluminescence immunoassay (CLIA) technology for the in vitro quantitative determination of Procalcitonin in human serum and lithium heparin plasma specimens. Used in conjunction with other laboratory findings and clinical assessments, LIAISON BRAHMS PCT II GEN is intended for use as follows:
- to aid in the risk assessment of critically ill patients on their first day of ICU admission for progression to severe sepsis and septic shock,
- to aid in assessing the cumulative 28-day risk of all-cause mortality for patients diagnosed with severe sepsis or septic shock in the ICU or when obtained in the emergency department or other medical wards prior to ICU admission, using a change in PCT level over time.
- to aid in decision making on antibiotic therapy for patients with suspected or confirmed lower respiratory tract infections (LRTI) defined as community-acquired pneumonia (CAP), acute bronchitis, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) – in an inpatient setting or an emergency department,
- to aid in decision making on antibiotic discontinuation for patients with suspected or confirmed sepsis.
The LIAISON Control BRAHMS PCT (level 1 and level 2) are intended for use as assayed quality control samples to monitor the performance and reliability of the LIAISON BRAHMS PCT II GEN assay. The performance characteristics of LIAISON BRAHMS PCT II GEN controls have not been established with any other assay or instrument platform different from the LIAISON Analyzer.
The LIAISON BRAHMS PCT II GEN calibration verifiers (four levels) are assayed quality control materials intended in the quantitative verification of calibration and reportable range of the LIAISON BRAHMS PCT II GEN assay. The performance characteristics of LIAISON BRAHMS PCT® II GEN calibration verifiers have not been established in connection with any other assay or instrument platforms different from the LIAISON Analyzer.
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2. Indications for use(s):
Same as Intended Use.
3. Special conditions for use statement(s):
For in vitro diagnostic use only
For prescription use only
4. Warnings and Precautions:
- LIAISON BRAHMS PCT II GEN ASSAY is not indicated to be used as a stand-alone diagnostic assay and should be used in conjunction with clinical signs and symptoms of infection and other diagnostic evidence.
- Decisions regarding antibiotic therapy should NOT be based solely on procalcitonin concentrations.
- PCT results should always be interpreted in the context of the clinical status of the patient and other laboratory results. Changes in PCT levels for the prediction of mortality, and overall mortality, are strongly dependent on many factors, including pre-existing patient risk factors and clinical course.
- The need to continue ICU care at Day 4 and other covariates (e.g., age and SOFA score) are also significant predictors of 28-day cumulative mortality risk.
- Certain patient characteristics, such as severity of renal failure or insufficiency, may influence procalcitonin values and should be considered as potentially confounding clinical factors when interpreting PCT values.
- Increased PCT levels may be observed in severe illness such as polytrauma, burns, major surgery, prolonged or cardiogenic shock.
- PCT levels may not be elevated in patients infected by certain atypical pathogens, such as Chlamydia pneumoniae and Mycoplasma pneumoniae.
- The safety and performance of PCT-guided therapy for individuals younger than age 17 years, pregnant women, immunocompromised individuals or those on immunomodulatory agents, was not formally analyzed in the supportive clinical trials.
5. Special instrument requirements:
The submission demonstrates performance on the LIAISON Analyzer (Model 15970).
I. Device Description:
The method for the quantitative determination of PCT is a sandwich chemiluminescence immunoassay. A specific monoclonal antibody is coated on the magnetic particles (solid phase); another monoclonal antibody (specific for a different epitope of the procalcitonin
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molecule) is linked to an isoluminol derivative (isoluminol-antibody conjugate). During the first incubation, PCT present in calibrators, samples or controls binds to the antibody conjugate. Then the solid phase is added to the reaction. A sandwich is formed only in the presence of PCT molecules that bridge both antibodies. After the second incubation, the unbound material is removed with a wash cycle.
Subsequently, the starter reagents are added and a flash chemiluminescence reaction is thus induced. The light signal, and hence the amount of isoluminol-antibody conjugate, is measured by a photomultiplier as relative light units (RLU) and is indicative of PCT concentration present in calibrators, samples or controls.
1. Reagents:
LIAISON BRAHMS PCT II GEN is an in vitro diagnostic device consisting of two reagents provided in individual compartments within a plastic container called the Reagent Integral and two additional components provided in glass vials, separately from the Reagent Integral. The assay configuration allows performance of 100 tests.
Materials provided in LIAISON BRAHMS PCT II GEN assay:
| Magnetic particles (2.5 mL) | [SORB] | Magnetic particles (suspension) coated with anti-katacalcin mouse monoclonal antibody, BSA, PBS buffer, < 0.1% sodium azide. |
| --- | --- | --- |
| Conjugate (13 mL) | [CONJ] | Anti-calcitonin rat monoclonal antibody conjugated to an isoluminol derivative, non-specific IgG (mouse, sheep and bovine polyclonal), BSA, PBS buffer, 0.2% ProClin®, and preservatives |
Included in the kit:
| Calibrator A (1.3 mL) | [CAL|A] | Recombinant human procalcitonin, PBS buffer, BSA, anti-proteases (lyophilized reagent). |
| --- | --- | --- | --- |
| Calibrator B (1.3 mL) | [CAL|B] | Recombinant human procalcitonin, PBS buffer, BSA, anti-proteases (lyophilized reagent). |
Materials required but not provided:
- LIAISON Analyzer
- LIAISON Module ([REF] 319130)
- LIAISON Starter Kit ([REF] 319102)
- LIAISON Light Check 12 ((REF) 319150)
- LIAISON Wash/System Liquid ([REF] 319100)
- LIAISON Waste Bags ([REF] 9450003)
- LIAISON Cleaning Kit ([REF] 310990)
- LIAISON Control BRAHMS PCT II GEN, levels 1 and 2, Diluent ([REF] 318091).
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- LIAISON BRAHMS PCT II GEN Verifiers, (four levels), Diluent ([REF] 318092).
J. Substantial Equivalence Information:
1. Predicate device name(s):
VIDAS BRAHMS PCT
2. Predicate 510(k) number(s):
K162827
3. Comparison with predicate:
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| Similarities | | |
| --- | --- | --- |
| Item | Candidate Device: LIAISON BRAHMS PCT II GEN (K173683) | Predicate Device: VIDAS BRAHMS PCT (K162837) |
| **Intended Use** | The LIAISON BRAHMS PCT II GEN assay uses chemiluminescence immunoassay (CLIA) technology for the in vitro quantitative determination of Procalcitonin in human serum and lithium heparin plasma specimens. Used in conjunction with other laboratory findings and clinical assessments, LIAISON BRAHMS PCT II GEN intended for use as follows:
- to aid in the risk assessment of critically ill patients on their first day of ICU admission for progression to severe sepsis and septic shock,
- to aid in assessing the cumulative 28-day risk of all-cause mortality for patients diagnosed with severe sepsis or septic shock in the ICU or when obtained in the emergency department or other medical wards prior to ICU admission, using a change in PCT level over time,
- to aid in decision making on antibiotic therapy for patients with suspected or confirmed lower respiratory tract infections (LRTI) defined as community-acquired pneumonia (CAP), acute bronchitis, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) – in an inpatient setting or an emergency department,
- to aid in decision making on antibiotic discontinuation for patients with suspected or confirmed sepsis. | VIDAS BRAHMS PCT (PCT) is an automated test for use on the instruments of the VIDAS family for the determination of human procalcitonin in human serum or plasma (lithium heparin) using the ELFA (Enzyme-Linked Fluorescent Assay) technique. Used in conjunction with other laboratory findings and clinical assessments, VIDAS BRAHMS PCT is intended for use as follows:
- to aid in the risk assessment of critically ill patients on their first day of ICU admission for progression to severe sepsis and septic shock,
- to aid in assessing the cumulative 28-day risk of all-cause mortality for patients diagnosed with severe sepsis or septic shock in the ICU or when obtained in the emergency department or other medical wards prior to ICU admission, using a change in PCT level over time,
- to aid in decision making on antibiotic therapy for patients with suspected or confirmed lower respiratory tract infections (LRTI) defined as community-acquired pneumonia (CAP), acute bronchitis, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) – in an inpatient setting or an emergency department,
- to aid in decision making on antibiotic discontinuation for patients with suspected or confirmed sepsis |
| Sample Matrix | Serum and Lithium Heparin plasma | Serum and Lithium Heparin plasma |
| Calibrators | Two | Two |
| Controls | Two (Low and High) | Two (Low and High) |
| Reagent Storage | 2-8°C Onboard or in Refrigerator | 2-8°C, Refrigerator |
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| Differences | | |
| --- | --- | --- |
| Item | Candidate Device: LIAISON BRAHMS PCT II GEN (K173683) | Predicate Device: VIDAS BRAHMS PCT (K162837) |
| Type of Assay | Chemiluminescent Immunoassay | Enzyme Immunoassay |
| Detection | CLIA - Chemiluminescence Immunoassay | ELFA - Enzyme-Linked Fluorescent Assay |
| Sample Handling/Processing | Automated | Manual |
| Detector | Anti-calcitonin antibody, labelled with isoluminol, monoclonal (mouse) | Alkaline phosphatase-labeled mouse monoclonal anti-human procalcitonin immunoglobulins |
| Capture Reagent | Magnetic particles coated with anti-katacalcin antibody, monoclonal (mouse) | Microwells coated with mouse monoclonal anti-human procalcitonin immunoglobulins |
| Sample Volume | 225 μL specimen (75 μL specimen + 150 μL dead volume) | 200 μL |
| Measurement System | Photomultiplier (flash chemiluminescence reader) | Spectrophotometer (EIA Microtiter plate reader) |
| Total Incubation | 40 minutes | 20 minutes |
| Control Similarities and Differences | | |
| --- | --- | --- |
| Item | Candidate Device: LIAISON Controls BRAHMS PCT II GEN (K173683) | Predicate Device: VIDAS BRAHMS PCT (K162837) |
| Intended Use | Same | Intended for use as assayed quality control samples to monitor the performance of the LIAISON BRAHMS PCT II GEN assay |
| Matrix | Recombinant Procalcitonin Antigen | Recombinant human PCT |
| Storage | Same | 2-8°C |
| Quantity & Volume | 2 x 1.1 mL (lyophilized) | 2 x 2 mL (lyophilized) |
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| Calibration Verifiers Similarities and Differences | | |
| --- | --- | --- |
| Item | Candidate Device: LIAISON BRAHMS PCT II GEN Verifiers (K173683) | Predicate Device: LIAISON XL 1,25 Dihydroxyvitamin D Calibration Verifiers (K141463) |
| Intended Use | Assayed quality control materials intended in the quantitative verification of calibration and reportable range of the LIAISON BRAHMS PCT II GEN assay. | Assayed quality control materials intended for the quantitative verification of calibration and reportable range of the LIAISON XL 1,25 Dihydroxyvitamin D |
| Product Storage | Same | 2 to 8°C until ready to use |
| Levels | Same | 4 levels; lyophilized |
| Quantity & Volume | 1.1 mLs | 2.0 mLs |
# K. Standard/Guidance Document Referenced (if applicable):
- CLSI Guideline EP05-A3 - Evaluation of Precision Performance of Quantitative Measurements and Methods; Approved Guideline; Third Edition.
- CLSI Guideline EP06-A, Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach; Approved Guideline.
- CLSI Guideline EP07-A2, Interference Testing in Clinical Chemistry; Second Edition
- CLSI Guideline EP09-A3, Measurement Procedure Comparison and Bias Estimation Using Patient Samples; Approved Guideline; Third Edition.
- CLSI Guideline EP15-A3, User Verification of Precision and Estimation of Bias; Third Edition
- CLSI Guideline EP17-A2, Protocol for Determination of Limits of Detection and Limits of Quantitation; Approved Guideline; Second Edition.
- CLSI Guideline EP28-A3c, Defining, Establishing and Verifying Reference Intervals in the Clinical Laboratory; Third Edition
# L. Test Principle:
The method for the quantitative determination of PCT is a sandwich chemiluminescence immunoassay.
A specific monoclonal antibody is coated on the magnetic particles (solid phase); another monoclonal antibody (specific for a different epitope of the procalcitonin molecule) is linked to an isoluminol derivative (isoluminol-antibody conjugate).
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During the first incubation, PCT present in calibrators, samples or controls binds to the antibody conjugate. Then the solid phase is added to the reaction. A sandwich is formed only in the presence of PCT molecules that bridge both antibodies. After the second incubation, the unbound material is removed with a wash cycle.
Subsequently, the starter reagents are added and a flash chemiluminescence reaction is thus induced. The light signal, and hence the amount of isoluminol-antibody conjugate, is measured by a photomultiplier as relative light units (RLU) and is indicative of PCT concentration present in calibrators, samples or controls.
Note: This assay does not use the biotin-streptavidin capture method; as such it is not susceptible to biotin interference.
## M. Performance Characteristics:
### 1. Analytical performance:
#### a. Precision:
A twenty-day precision study was performed internally at DiaSorin Inc. A panel comprised of ten (10) frozen serum samples spanning the assay range was prepared by DiaSorin. One (1) lot of LIAISON Control BRAHMS PCT II GEN (2 levels) and one (1) lot of LIAISON BRAHMS PCT II GEN verifiers (4 levels) were also tested in the study. Studies were performed in accordance with CLSI guideline EP5-A3, "Evaluation of Precision Performance of Quantitative Measurement Methods".
The precision panel samples, kit controls and verifiers were tested on two (2) lots of LIAISON BRAHMS PCT II GEN in two (2) replicates per run, two (2) runs per day for 20 operating days on one (1) LIAISON Analyzer with multiple operators.
Analysis of the total level of precision across lots demonstrated by the LIAISON BRAHMS PCT II GEN assay for the kit controls ranged from 6.1 – 6.5%, the verifiers (CVA-D) ranged from 5.5 – 8.7%, and the serum sample set ranged from 5.5 – 17.1%. Summary of precision results are represented in the Table below.
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Table 1: Summary of Combined Lot Precision Results
| Sample ID | n | Mean PCT (ng/mL) | Between-Lot | | Total (Across Lots) | |
| --- | --- | --- | --- | --- | --- | --- |
| | | | SD | %CV | SD | %CV |
| Kit Control 1 | 160 | 1.36 | 0.03 | 2.0% | 0.09 | 6.5% |
| Kit Control 2 | 160 | 45.8 | 0.25 | 0.6% | 2.82 | 6.1% |
| CV A | 160 | 0.47 | 0.02 | 3.7% | 0.04 | 8.7% |
| CV B | 160 | 1.78 | 0.04 | 2.1% | 0.13 | 7.0% |
| CV C | 160 | 6.33 | 0.10 | 1.7% | 0.35 | 5.5% |
| CV D | 160 | 43.6 | 0.58 | 1.3% | 2.69 | 6.2% |
| P001 | 158 | 0.12 | 0.00 | 3.1% | 0.02 | 16.6% |
| P002 | 158 | 0.11 | 0.01 | 6.2% | 0.02 | 17.1% |
| P003 | 160 | 0.29 | 0.01 | 3.7% | 0.03 | 11.8% |
| P004 | 160 | 0.28 | 0.00 | 0.6% | 0.03 | 12.3% |
| P005 | 160 | 0.59 | 0.01 | 2.0% | 0.05 | 8.9% |
| P006 | 160 | 0.59 | 0.00 | 0.7% | 0.06 | 10.3% |
| P007 | 160 | 2.21 | 0.03 | 1.4% | 0.22 | 10.0% |
| P008 | 160 | 2.24 | 0.04 | 1.9% | 0.15 | 6.6% |
| P009 | 160 | 24.4 | 0.17 | 0.7% | 1.84 | 7.5% |
| P010 | 160 | 67.8 | 1.06 | 1.6% | 3.74 | 5.5% |
# b. Reproducibility:
A five (5) day reproducibility study was performed at two (2) external laboratories and internally at DiaSorin Inc. to verify the reproducibility of the LIAISON BRAHMS PCT II GEN assay.
The precision panel samples, kit controls, and verifiers were tested on one (1) lot of LIAISON BRAHMS PCT II GEN in three (3) replicates per run, two (2) runs per day for five (5) operating days on three (3) LIAISON Analyzers with multiple operators performing the testing. Studies were performed in accordance with CLSI guideline EP15-A3, "User Verification of Precision and Estimation of Bias".
The observed reproducibility (%CV) across the three (3) testing sites from the five (5) day study for the LIAISON BRAHMS PCT II GEN assay for sample doses 0.129 ng/mL to 70.9 ng/mL ranged from $4.8\% - 16.8\%$ and across lots and sites for kit controls and calibration verifiers $4.9\% - 9.1\%$ . Summary of reproducibility results are represented in the Table below.
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Table 2: Summary of Reproducibility Results
| Sample ID | Mean PCT (ng/mL) | Within Run | | Between Day | | Site to Site | | Total | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Kit Control 1 Lot 1 | 1.4 | 0.05 | 3.2% | 0.05 | 3.8% | 0.07 | 5.2% | 0.10 | 7.1% |
| Kit Control 2 Lot 1 | 42.92 | 1.08 | 2.5% | 2.15 | 5.0% | 2.34 | 5.4% | 3.32 | 7.7% |
| Kit Control 1 Lot 2 | 1.39 | 0.04 | 3.1% | 0.05 | 3.6% | 0.08 | 5.6% | 0.10 | 7.3% |
| Kit Control 2 Lot 2 | 46.25 | 1.77 | 3.8% | 1.82 | 3.9% | 1.27 | 2.7% | 2.75 | 5.9% |
| CV A Lot 1 | 0.48 | 0.03 | 5.8% | 0.03 | 5.3% | 0.02 | 4.4% | 0.04 | 8.6% |
| CV B Lot 1 | 1.83 | 0.07 | 3.6% | 0.06 | 3.4% | 0.12 | 6.6% | 0.15 | 8.1% |
| CV C Lot 1 | 6.45 | 0.19 | 2.9% | 0.21 | 3.2% | 0.36 | 5.6% | 0.45 | 7.0% |
| CV D Lot 1 | 44.3 | 1.13 | 2.6% | 1.03 | 2.3% | 1.62 | 3.7% | 2.18 | 4.9% |
| CV A Lot 2 | 0.385 | 0.02 | 5.8% | 0.02 | 4.6% | 0.02 | 5.8% | 0.04 | 9.1% |
| CV B Lot 2 | 1.75 | 0.05 | 3.0% | 0.05 | 3.0% | 0.07 | 4.0% | 0.10 | 5.7% |
| CV C Lot 2 | 8.48 | 0.31 | 3.6% | 0.45 | 5.2% | 0.53 | 6.3% | 0.75 | 8.8% |
| CV D Lot 2 | 43.14 | 0.92 | 2.1% | 1.28 | 3.0% | 1.63 | 3.8% | 2.23 | 5.2% |
| P001 | 0.135 | 0.01 | 10.7% | 0.01 | 9.3% | 0.01 | 4.0% | 0.02 | 14.0% |
| P002 | 0.129 | 0.02 | 12.3% | 0.01 | 6.9% | 0.01 | 10.4% | 0.02 | 16.8% |
| P003 | 0.321 | 0.01 | 3.6% | 0.01 | 4.0% | 0.02 | 5.5% | 0.02 | 7.6% |
| P004 | 0.312 | 0.03 | 8.6% | 0.02 | 6.6% | 0.02 | 7.1% | 0.04 | 12.5% |
| P005 | 0.651 | 0.03 | 3.8% | 0.03 | 4.3% | 0.04 | 5.3% | 0.05 | 7.7% |
| P006 | 0.65 | 0.03 | 3.9% | 0.04 | 5.4% | 0.04 | 5.9% | 0.06 | 8.8% |
| P007 | 2.39 | 0.06 | 2.5% | 0.08 | 3.3% | 0.14 | 5.7% | 0.17 | 7.0% |
| P008 | 2.43 | 0.07 | 2.7% | 0.13 | 5.2% | 0.14 | 5.7% | 0.20 | 8.0% |
| P009 | 26.37 | 0.80 | 3.0% | 1.01 | 3.8% | 0.62 | 2.3% | 1.39 | 5.3% |
| P010 | 70.9 | 2.76 | 3.9% | 1.90 | 2.7% | 1.28 | 1.8% | 3.40 | 4.8% |
# c. Linearity/Assay Reportable Range:
# Linearity:
Linearity of the LIAISON BRAHMS PCT II GEN assay was assessed according to CLSI guideline EP6-A, "Evaluation of the Linearity of Quantitative Measurement Procedures". The linearity was performed on one (1) LIAISON BRAHMS PCT II GEN assay lot using a high patient-specimen pool (above $250\mathrm{ng / mL}$ ) of each sample type (serum, lithium heparin plasma). Samples were spiked with PCT or used neat to achieve a level slightly above the upper end of the assay's measuring range of 100 ng/mL. The samples were then diluted into 13 evenly spaced intervals to reach the minimum doses below the lower limit of reading range $(0.05\mathrm{ng / mL} - \mathrm{LoQ})$ . Dilutions were performed in LIAISON BRAHMS PCT II GEN Control Diluent. Each sample was tested in three (3) replicates in random sequence. The results were analyzed by %
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bias of observed analyte concentration versus expected analyte concentration.
Linearity was confirmed in the range of 0.05 ng/mL to 100 ng/mL. The measuring-range claim for the LIAISON BRAHMS PCT II GEN assay is 0.02–100 ng/mL.
Table 3: Linearity – Lithium Heparin Plasma matrix
| Lithium Heparin Matrix | Obtained | Expected | %Bias | CV% |
| --- | --- | --- | --- | --- |
| Dilution factor | ng/ml | P01-P | P01-P | P01-P |
| - | 217.6* | 217.6* | - | - |
| 1:2 | 108.8* | 108.8* | - | - |
| 1:4 | 54.4 | 54.4 | - | 1.5% |
| 1.8 | 29.2 | 27.2 | 7% | 1.4% |
| 1:16 | 13.9 | 13.6 | 2% | 1.4% |
| 1:32 | 7.99 | 6.80 | 18% | 0.4% |
| 1:64 | 3.65 | 3.40 | 7% | 0.3% |
| 1: 128 | 1.90 | 1.70 | 12% | 2.1% |
| 1: 256 | 0.99 | 0.85 | 16% | 2.3% |
| 1: 512 | 0.48 | 0.43 | 12% | 0.6% |
| 1: 1024 | 0.25 | 0.21 | 16% | 1.8% |
| 1: 2048 | 0.11 | 0.11 | 5% | 6.6% |
| 1: 4096 | 0.05 | 0.05 | -5% | 10.8% |
| 1:8192 | <<0.05 | 0.03 | - | - |
| Diluent | <<0.05 | - | | |
| *based on dilution factor Average %Bias and CV | | | 9% | 3% |
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Table 4: Linearity - Serum matrix
| Serum MATRIX | Obtained | Expected | %Bias | CV% |
| --- | --- | --- | --- | --- |
| Dilution factor | ng/ml | P01-S | P01-S | P01-S |
| - | 236.4* | 236.4* | - | - |
| 1:2 | 118.2* | 118.2* | - | - |
| 1:4 | 59.07 | 59.07 | - | 1.5% |
| 1.8 | 31.2 | 29.5 | 5.7% | 0.4% |
| 1:16 | 15.2 | 14.8 | 3.1% | 2.1% |
| 1:32 | 8.28 | 7.39 | 12.1% | 1.5% |
| 1:64 | 3.92 | 3.69 | 6.1% | 1.6% |
| 1: 128 | 1.94 | 1.85 | 5.2% | 1.3% |
| 1: 256 | 1.01 | 0.92 | 8.9% | 1.7% |
| 1: 512 | 0.53 | 0.46 | 15.8% | 5.6% |
| 1: 1024 | 0.27 | 0.23 | 18.7% | 1.0% |
| 1: 2048 | 0.12 | 0.12 | -0.4% | 0.9% |
| 1: 4096 | 0.06 | 0.06 | 3.2% | 4.9% |
| 1:8192 | <<0.05 | 0.03 | - | - |
| Diluent | <<0.05 | - | | |
| *based on dilution factor Average %Bias and CV | | | 7.8% | 2.0% |
# Dilution Tests:
Linearity was evaluated according to CLSI EP6-A2 samples (serum and lithium heparin plasma matrix) containing high PCT concentration were tested neat and after serially diluting with the LIAISON BRAHMS PCT II GEN Diluent and analyzed. The results were analyzed as a linear regression of the Expected vs. Observed values. The resulting regression equation is:
Lithium heparin plasma Observed PCT = 0.99(Expected) + 0.34; R²= 1.00
Serum Observed PCT= 0.99(Expected) + 0.30; R²= 1.00
d. Traceability, Stability, Expected Values (controls, calibrators, or methods):
# i. Calibrators:
The LIAISON BRAHMS PCT II GEN assay contains two calibrators consisting of recombinant human procalcitonin, PBS buffer, BSA and anti-proteases (lyophilized reagent).
| LIAISON BRAHMS PCT II GEN Calibrators | | |
| --- | --- | --- |
| Sample ID | Range (mg/mL) | |
| | Lower Limit | Upper Limit |
| Calibrator A | 0.1 ng/mL | 0.5 ng/mL |
| Calibrator B | 30 ng/mL | 70 ng/mL |
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LIAISON BRAHMS PCT II GEN Calibration Verifiers:
LIAISON BRAHMS PCT II GEN Verifiers are assayed quality control materials intended for the quantitative verification of calibration and reportable range of the LIAISON BRAHMS PCT II GEN assay.
The four levels of calibration verifiers (A-D) are intended to span the assay range of the LIAISON BRAHMS PCT II GEN assay. The target concentrations for each lot of calibration verifiers are assigned at DiaSorin by testing several replicates of each concentration in multiple runs, on multiple instruments using multiple lots of LIAISON BRAHMS PCT II GEN assay integrals and controls.
Concentrations and ranges assigned by DiaSorin to each Calibration Verifier are provided on a Certificate of Analysis.
| LIAISON BRAHMS PCT II GEN Verifiers | | | |
| --- | --- | --- | --- |
| Sample ID | Target Dose | Range (mg/mL) | |
| | | Lower Limit | Upper Limit |
| Verifier A | 0.5 ng/mL | 0.33 | 0.68 |
| Verifier B | 2.0 ng/mL | 1.3 | 2.7 |
| Verifier C | 8.0 ng/mL | 5.2 | 10.8 |
| Verifier D | 50 ng/mL | 32.5 | 67.5 |
ii. Controls:
The LIAISON Control BRAHMS PCT II GEN (level 1 and level 2) are intended for use as assayed quality control samples to monitor the performance and reliability of the LIAISON BRAHMS PCT II GEN assay.
The range of concentrations of each control is reported on the certificate of analysis and indicates the limits established by DiaSorin for control values that can be obtained in reliable assay runs. The certificates of analysis bar codes give specific information on the lot of controls.
| LIAISON Control BRAHMS PCT II GEN | | |
| --- | --- | --- |
| Sample ID | Range (mg/mL) | |
| | Lower Limit | Upper Limit |
| Control Level 1 | 0.6 ng/mL | 2.4 ng/mL |
| Control Level 2 | 16.0 ng/mL | 64.0 ng/mL |
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iii. Stability:
Reagent Stability: Real-Time Shelf Life:
In the real-time, shelf-life stability study, the LIAISON BRAHMS PCT II GEN was stored at 2–8°C at predetermined intervals. The stored assay was tested at time point 0 (at manufacture), 2, 4, 6, 9, 12, 15, 18, 19, 21, 24, 25 and 26 months (up to the planned shelf life plus one month) using three (3) assay lots. The LIAISON Control BRAHMS PCT II GEN and QC panel samples were tested in singlicate. The average recovery value was calculated as percent recovery compared to the assigned PCT values.
Testing demonstrated that the LIAISON BRAHMS PCT II GEN assay reagents are stable for 24 months at 2–8°C based on real-time stability data.
Calibration Stability Testing:
Calibrator stability for the LIAISON BRAHMS PCT II GEN assay was evaluated using QC panel samples and kit controls tested in singlicate. The opened Reagent Integrals were evaluated at 1, 2, 3, 4, 5, 6, 7, 8, and 9 weeks. Results were generated using the initial (time zero) assay calibration.
Testing demonstrated that the calibration of the LIAISON BRAHMS PCT II GEN is stable for at least 8 weeks when the integral is properly stored on-board the analyzer.
Stability of Reconstituted Calibrators – Freeze/Thaw Cycles:
A study was performed to assess stability of the reconstituted LIAISON BRAHMS PCT II GEN calibrators by simulating normal condition of use as specified in the Instructions for Use (i.e. repeated freeze-thaw between successive tests). Reconstituted calibrators were pooled, then frozen and tested after 1, 2, 3, 4, and 5 freeze/thaw cycles. After each freeze/thaw cycle the frozen calibrators were used to calibrate the LIAISON BRAHMS PCT II GEN assay. The time zero assay was calibrated with freshly reconstituted (unfrozen) calibrators. At each test point kit controls and QC panel samples were tested in duplicate and doses calculated.
The resulting data supports that after reconstitution; calibrators of the LIAISON BRAHMS PCT II GEN can be frozen and thawed up to 4 times. In the Instructions for Use a maximum of three freeze-thaw cycles for calibrators will be allowed, corresponding to four calibrations (maximum number of calibrations allowed with the volume/vial available after reconstitution).
Stability of Reconstituted Calibrators – Frozen Storage:
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A study was performed to assess stability of the reconstituted LIAISON BRAHMS PCT II GEN calibrators by simulating normal condition of use as specified in the Instructions for Use (i.e. stored frozen between two successive tests). Calibrators of both levels were opened at time zero, reconstituted, pooled, and divided into aliquots in order to cover the whole study. One (1) aliquot was used for testing at time zero, the other aliquots were frozen and tested after 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 weeks. At each test point, the LIAISON PCT II GEN Reagent Integral was calibrated using a frozen calibrator aliquot. QC panel samples and freshly opened kit controls were run and doses calculated.
The resulting data supports the LIAISON BRAHMS PCT II GEN assay package-insert claim of calibration is stable when stored frozen for 12 weeks.
In Use Reagent Integral – Open/On Board Stability:
Reagent on-board stability for the LIAISON BRAHMS PCT II GEN assay was assessed by simulating normal condition of use as specified in the Instructions for Use (i.e. storage on board the analyzers between two successive tests). Test was calibrated; kit controls and QC panel samples were tested. The Reagent Integrals were then stored on board the analyzer in the reagent bay area. Kit performance using the opened Reagent Integrals was evaluated weekly through 13 weeks. Results were generated using the initial (time zero) assay calibration.
The resulting data support the LIAISON BRAHMS PCT II GEN assay package-insert claim of that the Reagent Integral is stable for at least 12 weeks when stored open/on board analyzer.
Kit Control Long Term Stability:
The long-term stability of the LIAISON Control BRAHMS PCT II GEN was assessed with three (3) lots of LIAISON Control BRAHMS PCT II GEN stored at 2-8°C with three (3) lots of LIAISON BRAHMS PCT II GEN assays. Kit Controls were tested opened at each time point with a freshly opened and calibrated Reagent Integral. Tests were performed with a fixed frequency for the entire period through 25 months to guarantee adequate confidence and in order to have data supporting the assignment of a 24 month expiration date.
The resulting data supports the LIAISON BRAHMS PCT II GEN assay package-insert claim that the LIAISON Control BRAHMS PCT II GEN is stable for 24 months when stored 2-8°C.
Stability of Reconstituted Kit Controls – Freeze/Thaw Cycles:
A study was performed to assess stability of the reconstituted LIAISON Control
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BRAHMS PCT II GEN by simulating normal condition of use as specified in the Instructions for Use (i.e. repeated freeze-thaw between two successive tests). Reconstituted controls were pooled, then frozen and tested after 1, 2, 3, 4, 5, 6, 7, and 8 freeze/thaw cycles.
The resulting data supports that the LIAISON Control BRAHMS PCT II GEN can be thawed up to 7 times.
## Stability of Reconstituted Controls – Frozen Storage
A study was performed to assess stability of the reconstituted LIAISON Control BRAHMS PCT II GEN by simulating normal condition of use as specified in the Instructions for Use (i.e. stored frozen between two successive tests). Controls were opened at time zero, reconstituted, pooled, and divided into aliquots in order to cover the whole study. One aliquot was used for testing at time zero, the other aliquots were frozen and tested after 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19 weeks.
The resulting data demonstrated that the LIAISON Control BRAHMS PCT II GEN is stable for at least 18 weeks when stored frozen after reconstitution. In the Instructions for Use a maximum of 8 weeks storage will be reported for reconstituted Controls when stored frozen.
## Diluent Open Stability:
A study was performed to assess stability of the opened diluent vials by simulating normal condition of use as specified in the Instructions for Use (i.e. in the refrigerator between two successive tests) in order to estimate the time within which it can be used as a diluent for controls and as a diluent for out of range samples. Three (3) lots of diluent were opened and tested at time zero and then stored at 2-8°C. At 3 and 5 months the diluent was used for the reconstitution of the kit controls. Reconstituted controls at each time point were tested on a freshly opened integral in parallel with controls reconstituted with a freshly open diluent (Reference Condition).
The resulting data demonstrates that the LIAISON BRAHMS PCT II GEN diluent provided with the LIAISON Control BRAHMS PCT II Gen is stable for at least 3 months after opening, when properly stored at 2-8°C. In the Instructions for Use, a maximum of 3 months storage will be reported for open diluent.
iv. Reference Interval (Expected values/Reference Range):
To establish the reference interval of normal population for LIAISON BRAHMS PCT II GEN Assay, serum samples from 120 apparently healthy adults ≥ 19 years of age were tested using the LIAISON BRAHMS PCT II GEN
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Assay according to CLSI EP28-A3c, Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory guideline.
The reference interval range of the normal population using the LIAISON BRAHMS PCT II GEN Assay median reference range limit was calculated at 0.08 ng/mL.
Table 5: Summary of Normal Healthy Donor Population Demographics
| Age Range | N | Ethnicity | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | African American | Asian | Caucasian | Hispanic | Other |
| <60 | 117 | 46 | 0 | 34 | 36 | 1 |
| ≥60 | 3 | 0 | 0 | 3 | 0 | 0 |
Table 6: Summary of Reference Interval Study
| Population (n=120) | Median | Observed Range 2.5th to 97.5th Percentile |
| --- | --- | --- |
| United States | 0.08 ng/mL | < 0.05 ng/mL – 0.16 ng/mL |
e. Limit of Blank (LoB):
The Limit of Blank (LoB) of the LIAISON BRAHMS PCT II GEN assay was determined according to CLSI guideline EP17-A2, "Evaluation of Precision Performance of Quantitative Measurement Methods". The LoB is the highest observed measurement value for an analyte-free sample. The LoB was determined as the 95th percentile of blank-sample measurements.
The distribution of values for five (5) analyte-free serum samples was determined with two (2) reagent lots on two (2) LIAISON Analyzers by different operators over three (3) days for four (4) runs with each of the two (2) reagent lots. The samples were measured in two-fold determination for each run. A total of 60 measuring points were collected.
The LoB value was determined to be 0.01 ng/mL. The LoB claim for the LIAISON BRAHMS PCT II GEN assay is 0.01 ng/mL. The results are shown in the table below.
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Table 7: Summary of LoB Results
| | instrument 2229000511 | | instrument 2229000847 | |
| --- | --- | --- | --- | --- |
| | 239001X | 239002X | 239001X | 239002X |
| Blank RLU Mean | 572 | 599 | 695 | 667 |
| Blank RLU SD | 66 | 113 | 85 | 102 |
| RLU LoB | 682 | 788 | 837 | 838 |
| Dose LoB | 0.01 | 0.01 | 0.01 | 0.01 |
f. Limit of Detection (LoD):
The Limit of Detection (LoD) of the LIAISON BRAHMS PCT II GEN assay was determined according to CLSI guideline EP17-A2, "Protocol for Determination of Limits of Detection and Limits of Quantitation". The distribution of values for four (4) low-level human serum samples was determined with two (2) reagent lots on two (2) LIAISON Analyzers over three (3) days for twelve (12) results per sample.
The LoD value was determined to be $0.02\mathrm{ng / mL}$ . The LoD claim for the LIAISON BRAHMS PCT II GEN assay is $0.02\mathrm{ng / mL}$ . The results are shown in the tables below.
Table 8: LoD Study Results - Data Kit Lot 1 (239001X) - LIAISON Analyzer 1 (2229000511) and LIAISON Analyzer 2 (2229000847)
| Lot# | 239001X | | | | 239001X | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Instrument # | 2229000511 | | | | 2229000847 | | | |
| Sample # | Sample 1 | Sample 2 | Sample 3 | Sample 4 | Sample 1 | Sample 2 | Sample 3 | Sample 4 |
| Mean (ng/ml) | 0.0033 | 0.0033 | 0.0058 | 0.0272 | 0.0000 | 0.0089 | 0.0270 | 0.0412 |
| SD (ng/ml) | 0.0041 | 0.0041 | 0.003 | 0.0049 | 0.0000 | 0.0050 | 0.0073 | 0.0085 |
| %CV (ng/ml) | - | - | 50.0% | 18.1% | - | 41.2% | 27.0% | 18.8% |
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Table 9: LoD Study Results - Data Kit Lot 2 (239002X) - LIAISON Analyzer 1 (2229000511) and LIAISON Analyzer 2(2229000847)
| Lot# | 239002X | | | | 239002X | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Instrument # | 2229000511 | | | | 2229000847 | | | |
| Sample # | Sample 1 | Sample 2 | Sample 3 | Sample 4 | Sample 1 | Sample 2 | Sample 3 | Sample 4 |
| Mean (ng/ml) | 0.0000 | 0.0005 | 0.0187 | 0.0414 | 0.0000 | 0.0000 | 0.0111 | 0.0250 |
| SD (ng/ml) | 0.0000 | 0.0003 | 0.0027 | 0.0157 | 0.0000 | 0.0000 | 0.0029 | 0.0022 |
| %CV (ng/ml) | - | 54.9% | 14.3% | 37.8% | - | - | 26.2% | 8.7% |
g. Limit of Quantitation (LoQ):
The Limit of Quantitation (LoQ) of the LIAISON BRAHMS PCT II GEN assay was determined according to CLSI guideline EP17-A2, "Protocol for Determination of Limits of Detection and Limits of Quantitation". The LoQ was calculated based on intermediate precision according to CLSI EP17-A2. The LoQ was determined as the lowest concentration of analyte that can be quantified with an intermediate precision of no more than 20%.
Nine (9) samples (4 of which were used in the LoD determination) with the remaining samples were set slightly below the LoB mean detection level and slightly above the estimated LoQ (used for LoQ calculations). Each of the samples were tested on two (2) LIAISON instruments with two (2) reagent kit lots by two (2) technicians, testing samples over four (4) runs and three (3) days, three (3) replicates per sample per run, twelve (12) results per sample to define LoQ. A third lot was tested to verify the LoQ result.
The LoQ was determined to be 0.04 ng/mL. The LoQ claim for the LIAISON BRAHMS PCT II GEN assay is 0.05 ng/mL.
The Limit of Quantitation LOQ expressed as dose with %Bias < 5%, %CV < 15% and %Total error < 30% is 0.05 ng/mL.
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Table 10: LOQ and Medical Decision Point
| PCT level (ng/mL) | CV% | Bias% | Total Error% |
| --- | --- | --- | --- |
| 0.05 | 14.0% | 2.7% | 25.8% |
| 0.10 | 15.0% | 0.3% | 25.1% |
| 0.25 | 13.0% | 1.4% | 22.9% |
| 0.50 | 10.3% | 3.0% | 19.9% |
| 2.0 | 6.8% | 4.0% | 15.3% |
In summary, the detection limits for the LIAISON BRAHMS PCT II GEN assay were determined to be:
Table11: LoB, LoD, LoQ
| LoB | LoD | LoQ |
| --- | --- | --- |
| 0.01 g/mL | 0.02 g/mL | 0.05 g/mL |
# h. Analytical Specificity/Cross-Reactivity:
The analytical specificity in the presence potential cross-reacting compounds were evaluated with spiked PCT samples at different concentrations (close to all medical decision points, $0.1\mathrm{ng / mL}$ , $0.25\mathrm{ng / mL}$ , $0.5\mathrm{ng / mL}$ , $2\mathrm{ng / mL}$ , and close to the high level of the measuring range; approximately $70\mathrm{ng / mL}$ ) and tested with the LIAISON BRAHMS PCT II GEN assay. The results are shown in the table below:
Table 12: Analytical Specificity/Cross-Reactivity Data
| Substance | Concentration Tested | Results |
| --- | --- | --- |
| Human Calcitonin | 60 ng/mL | No interference observed |
| Human Katacalcin* | 30 ng/mL | No interference observed |
| Human alpha-CGRP* | 10 μg/mL | No interference observed |
| Human beta-CGRP* | 10 μg/mL | No interference observed |
*Calcitonin Gene Related Peptide
# i. Interfering Substances:
# Endogenous Interferences
The analytical specificity in the presence of endogenous substances were evaluated with spiked PCT samples at different concentrations (close to all medical decision points, $0.1\mathrm{ng / mL}$ , $0.25\mathrm{ng / mL}$ , $0.5\mathrm{ng / mL}$ , $2\mathrm{ng / mL}$ , and close to the high level of the measuring range; approximately $70\mathrm{ng / mL}$ ) and tested with the LIAISON BRAHMS PCT II GEN assay.
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The following endogenous substances evaluated with the LIAISON BRAHMS PCT II GEN assay were found not to affect the test performance at concentrations reasonably and consistently found in clinical situations.
Table 13: Endogenous Interference Study Results
| Substance | Concentration Tested | Results |
| --- | --- | --- |
| Triglycerides | 3,000 mg/dL | No interference observed |
| Hemoglobin | 1,000 mg/dL | No interference observed |
| Unconjugated bilirubin | 20 mg/dL | No interference observed |
| Conjugated bilirubin | 20 mg/dL | No interference observed |
| Protein – total protein (high) | 120 g/L | No interference observed |
| Protein – total protein (low) | < 60 g/L | No interference observed |
| RF (Rheumatoid Factor) | 2800 IU/mL | No interference observed |
| HAMA | 658 ng/mL | No interference observed |
| Cholesterol | 350 mg/dL | No interference observed |
Exogenous Interference:
Thirty pharmaceutical compounds were evaluated with spiked PCT samples at different concentrations (close to all medical decision points, 0.1 ng/mL, 0.25 ng/mL, 0.5 ng/mL, 2 ng/mL, and close to the high level of the measuring range; approximately 70 ng/mL) and tested with the LIAISON BRAHMS PCT II GEN assay.
The following substances evaluated with the LIAISON BRAHMS PCT II GEN assay were found not to affect the test performance at concentrations reasonably and consistently found in clinical situations.
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Table 14: Exogenous Interference Study Results
| Substance | Concentration Tested | Results |
| --- | --- | --- |
| Imipenim | 1,180,000 ng/mL2 | No interference observed |
| Cefotaxim | 180 mg/dL | No interference observed |
| Vancomycin | 3,500,000 ng/mL | No interference observed |
| Dopamine | 260,000 ng/mL | No interference observed |
| Noradrenaline | 4,000 ng/mL | No interference observed |
| Dobutamine | 22,400 ng/mL | No interference observed |
| Heparin | 40,000 ng/mL | No interference observed |
| Furosemide | 40,000 ng/mL | No interference observed |
| Acetaminophen | 20 mg/dL (1,324 μmol/l) | No interference observed |
| Amoxicillin | 7.5 mg/dL (206 μmol/l) | No interference observed |
| Azythromycin | 1.2 mg/dL (15.3 μmol/l) | No interference observed |
| Caffeine | 6 mg/dL (308 μmol/l) | No interference observed |
| Celecoxib=celebrex | 0.5 mg/ml | No interference observed |
| Cetirizine HCl | 0.003 mg/ml (7.7 μmol/l) | No interference observed |
| Dextramethorphan | 0.1 mg/dL (3.7 μmol/l) | No interference observed |
| Epinephrine | 1.18 μg/mL | No interference observed |
| Levoflaxacin | 1.8 mg/dL (48.6 μmol/l) | No interference observed |
| Nicotine | 0.1 mg/dL (6.2 μmol/l) | No interference observed |
| Oxymetazoline HCl | 0.05mg/ml | No interference observed |
| Phenylephrine | 0.035 mg/ml | No interference observed |
| Prednisolone | 0.3 mg/dL (8.31 μmol/l) | No interference observed |
| Theophylline | 4 mg/dL (222 μmol/l)) | No interference observed |
| Acetylsalicylic acid | 0.65 mg/mL (3.62 mmol/L)) | No interference observed |
| Alcohol - Ethanol | 4 mg/mL (86.8 mmol/L) | No interference observed |
| Doxycycline | 0.03 mg/mL (67.5 μmol/L) | No interference observed |
| Fentanyl | 15 ng/mL | No interference observed |
| Ibuprofen | 0.5 mg/mL (2,425 μmol/L) | No interference observed |
| Loratadine | 0.0003 mg/mL (0.78 μmol/L) | No interference observed |
| Salmeterol | 400 μg/mL | No interference observed |
| Tiotropium | 680 μg/mL | No interference observed |
# HAMA Effect:
Testing was performed to determine whether the presence of HAMA (Human anti-
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mouse antibody) may interfere with LIAISON BRAHMS PCT II GEN results.
HAMA and RF (Rheumatoid Factor) interference was assessed by testing one sample obtained by a pool of two high HAMA samples (mean HAMA level 658 ng/mL) and one sample at high RF level (2,800 IU/mL) plus LIAISON BRAHMS PCT II Gen Diluent (serum PCT free). A suitable HAMA/RF serum sample was spiked with PCT analyte at multiple concentrations covering the clinically relevant range and was tested in 26 replicates.
There was no HAMA/RF interference observed for PCT analyte with the presence of HAMA at 658 ng/mL and RF at 2,800 IU/mL.
j. High-Dose Hook Effect:
There is no high-dose hook effect at PCT concentrations up to 2,000 ng/mL PCT.
k. Spike and Recovery Effects:
A spike and recovery study was performed by using four (4) samples at low analyte concentrations spiked with known amount PCT levels to reach four concentrations (0.1, 0.25, 0.5, 2 ng/mL) and assayed. Percent recoveries were determined between obtained and expected concentrations.
% Recovery for each spiked sample was between 90-110%.
l. Analyte Carry-over:
A study was performed to access the carry-over of the LIAISON BRAHMS PCT II Gen assay by testing a series of alternating high, low and negative samples. Carryover testing was performed with a set of three (3) spiked samples. The set consisted of a sample with no PCT, a low PCT level (0.1ng/mL) and a high PCT level sample (4000 ng/mL).
No carry over observed was observed in the LIAISON BRAHMS PCT II GEN assay.
m. Drift Effect:
The drift effect is defined as the change in measurement value over time due to factors other than the concentration of the analyte which can be caused by delays in performing test steps such as dispensing of samples or one or more reagents with consequent different reaction times was assessed with the LIAISON BRAHMS PCT II GEN assay.
Six (6) samples and/or controls distributed across the measuring range of the assay (2 low, 2 middle, 2 high, or 2 near the medical decision level) were analyzed in six (6) replicates in each of two (2) runs for a total of 12 runs.
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Results demonstrated no observed drift effect in the LIAISON BRAHMS PCT II GEN assay.
a. Assay Cut-off:
28-day mortality:
- $\Delta \mathrm{PCT} \leq 80\%$
A decrease in the PCT levels below or equal to $80\%$ defines a positive $\Delta \mathrm{PCT}$ test result representing a higher risk for 28-day all-cause mortality of patients diagnosed with severe sepsis or septic shock.
- $\Delta \mathrm{PCT} > 80\%$
A decrease in the PCT levels of more than $80\%$ defines a negative $\Delta \mathrm{PCT}$ test result representing a lower risk for 28-day all-cause mortality of patients diagnosed with severe sepsis or septic shock.
NOTE: The combination of the first PCT level ($\leq 2.0 \, \mathrm{ng/mL}$ or $> 2.0 \, \mathrm{ng/mL}$) at initial diagnosis of severe sepsis or septic shock with the patient's clinical course and the change in PCT level over time until Day 4 provides important additional information about the mortality risk.
Progression Risk:
- $\mathrm{PCT} > 2\,\mu\mathrm{g}/\mathrm{L}$
A PCT level above $2.0\,\mu\mathrm{g}/\mathrm{L}$ on the first day of ICU admission is associated with a high risk for progression to severe sepsis and/or septic shock.
- $\mathrm{PCT} < 0.5\,\mu\mathrm{g}/\mathrm{L}$
A PCT level below $0.5\,\mu\mathrm{g}/\mathrm{L}$ on the first day of ICU admission is associated with a low risk for progression to severe sepsis and/or septic shock.
LRTI Antibiotic Decision Making:
- $\mathrm{PCT} < 0.10\,\mathrm{ng/mL}$
Antibiotic therapy strongly discouraged.
- $\mathrm{PCT} 0.10 - 0.25\,\mathrm{ng/mL}$
Antibiotic therapy discouraged.
- $\mathrm{PCT} 0.26 - 0.50\,\mathrm{ng/mL}$
Antibiotic therapy encouraged.
- $\mathrm{PCT} > 0.50\,\mathrm{ng/mL}$
Antibiotic therapy strongly encouraged.
Sepsis Antibiotic Discontinuation:
- $\Delta \mathrm{PCT} > 80\%$
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Antibiotic therapy may be discontinued
- PCT ≤ 0.50 ng/mL
Antibiotic therapy may be discontinued
Recommendations for Laboratory Reports for Initiation and Discontinuation:
The Change in Procalcitonin Calculator is available at www.BRAHMS-PCT-Calculator.com. The Change in Procalcitonin Calculator can be used to determine ΔPCT results. It is suggested to report the numerical PCT values (individual or paired). For paired PCT values the report should also indicate if the ΔPCT (%) was ≤ 80% or > 80%. The laboratory report should include a reference or a link to the package insert for a guided interpretation of the test results.
n. Specimen Stability:
Sample Stability at 2-8°C:
A study was performed to evaluate LIAISON BRAHMS PCT II GEN assay’s ability to generate analogous results when using fresh and stored samples. Five (5) samples at different analyte levels, four of them at the clinical decision points (0.1, 0.25, 0.5, 2 ng/mL) and one near the assay range (around 70 ng/mL) were evaluated for the effect of storage at 2-8°C. Each sample was divided into aliquots, one (1) aliquot was tested in duplicate fresh, and the rest of the aliquots were stored at 2-8°C. The aliquots were tested at their specified time points in duplicate after 24 and 25 hours at 2-8°C. Recovery compared to the reference value was calculated as either deviation (in ng/mL) or as percent recovery
Studies demonstrated that serum samples and Lithium Heparin Plasma specimens are stable for 24 hours at 2-8°C.
Sample Stability at 15-25°C:
A study was performed to evaluate LIAISON BRAHMS PCT II GEN assay’s ability to generate analogous results when using fresh and stored samples. Five (5) samples at different analyte levels, four (4) of them at the clinical decision points (0.1, 0.25, 0.5, 2 ng/mL) and one (1) along the assay range (around 70 ng/mL) were used. Each sample was divided into aliquots, one (1) aliquot was tested in duplicate fresh, and the rest of the aliquots were stored at room temperature. The aliquots were tested at their specified time points in duplicate. Each sample was tested fresh and after 24 and 25 hours at 2-8°C. Recovery compared to the reference value was calculated as either deviation (in ng/mL) or as percent recovery.
Studies demonstrated that serum samples and Lithium Heparin Plasma specimens are stable for 24 hours at room temperature.
Sample Stability at -20°C:
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A study was performed to evaluate LIAISON BRAHMS PCT II GEN assay's ability to generate analogous results when using fresh and stored samples. Sixty-five samples for each matrix (serum and lithium heparin) were tested. Samples were spiked with recombinant procalcitonin in order to contrive samples with analyte levels close to the cut off(s). Each sample was divided into six (6) aliquots and were tested fresh and after storage at -20°C or below for 1, 2, 3, 4, and 5 months. The aliquots were tested at their specified time points in triplicate. Recovery compared to the reference value was calculated as either deviation (in ng/mL) or as percent recovery
Studies demonstrated that serum samples and Lithium Heparin Plasma specimens are stable for three months at -20°C.
Additional sample stability studies were performed on the MOSES clinical samples as described in DEN150009.
Sample Stability (Freeze/Thaw Cycles) Study:
Sample Stability (Freeze/Thaw Cycles) was assessed by comparing the measurement of six (6) PCT samples distributed across the assay range, with four (4) samples close to the medical decision points (0.1, 0.25, 0.5 and 2 ng/mL). Each fresh sample was divided into four (4) aliquots, frozen and subjected to six (6) freeze/thaw cycles and was tested in duplicate.
Recovery compared to the reference value was calculated as either deviation (in ng/mL) or as percent recovery
Studies demonstrated that samples are stable through five (5) freeze/thaw cycles.
o. Matrix Equivalence Study:
Lithium-Heparin Plasma-Versus-Serum Comparison:
The effect on quantitation of PCT in the presence of lithium-heparin anticoagulant was determined by comparing values obtained from human samples drawn into Serum and Li-Heparin plasma primary tubes. Forty Serum/Li-Heparin plasma matched patient samples were collected spanning the full assay measuring range. Spiked or diluted samples were used in order to span the assay range. Paired samples were tested in triplicate in the same run using one (1) reagent lot and one (1) analyzer in order to exclude the effects of other variables on the results. Potential effects were assessed by Passing/Bablok regression analysis.
The results show no statistically significant difference between the Serum/Li-Heparin samples, thus supporting the package-insert claim that Li-Heparin plasma is an acceptable sample type for use with the LIAISON BRAHMS PCT II GEN assay.
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# 2. Method Comparison:
A quantitative method comparison study was performed on 349 serum samples and 20 lithium heparin plasma samples for a total of 369 samples following CLSI EP09-A2. Of the 369 samples, one hundred four (104) samples were not included in the analysis because they read $< 0.05 \mathrm{ng/mL}$ which is below the reading range of either or both assays and one (1) sample read $>100 \mathrm{ng/mL}$ on the LIAISON BRAHMS PCT II GEN assay and therefore was also removed from the analysis. The PCT sample results ranged from $0.05 \mathrm{ng/mL}$ to $131 \mathrm{ng/mL}$ .
Results for the VIDAS BRAHMS PCT assay and the LIAISON BRAHMS PCT II GEN assay were plotted. Passing Bablok and Weighted Deming regression analyses including slope and intercept with $95\%$ CI were calculated for all 264 samples that read across the measuring range of the assays. The results are summarized in the following graphs and tables.
# Passing and Bablok Regression Results (n=264):
Passing and Bablok regression analysis was applied to the results across the range of the LIAISON BRAHMS PCT II GEN assay yielding agreement of $y = 1.03x + 0.06$ . The $95\%$ confidence intervals for the slope were 1.01 to 1.05 and the $95\%$ confidence intervals for the intercept 0.04 to 0.07 ng/mL.
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Weighted Deming Results (n=264): Weighted Deming analysis was applied to the results across the range of the LIAISON BRAHMS PCT II GEN assay yielding agreement of y = 1.07x + 0.03. The 95% confidence intervals for the slope were 1.03 to 1.11 and the 95% confidence intervals for the intercept 0.02 to 0.05 ng/mL.
Weighted Deming regression, calculate bias at clinical decision points with 95% CI:
Bias was calculated at two medical decision points 0.50 and 2.0 ng mL with 95% CI
| Decision level | Bias | 95% CI | | Bias Calculation |
| --- | --- | --- | --- | --- |
| 0.5 | 0.06481 | 0.05021 | to 0.07941 | 13% |
| 2 | 0.16588 | 0.09894 | to 0.23283 | 8% |
A qualitative method comparison study was also performed on the 369 samples mentioned above. The samples were tested on the LIAISON BRAHMS PCT II GEN assay at two (2) laboratories and internally at DiaSorin. The samples were tested by the VIDAS BRAHMS PCT assay at an external reference laboratory. Results for the LIAISON BRAHMS PCT II GEN assay are provided in a percent agreement tables below.
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Table 15: % Agreement - 0.10 ng/mL PCT Clinical Decision Point
| | VIDAS BRAHMS PCT | | |
| --- | --- | --- | --- |
| LIAISON BRAHMS PCT II GEN | ≤0.10 ng/mL | >0.10 ng/mL | TOTAL |
| ≤0.10 ng/mL | 108 | 2 | 110 |
| >0.10 ng/mL | 17 | 242 | 259 |
| TOTAL | 125 | 244 | 369 |
Negative percent agreement 86.4% (79.3 - 91.3%)
Positive percent agreement 99.2% (97.1 - 99.8%)
Overall: 94.9% (93.0 - 96.7%)
Table 16: % Agreement - 0.25 ng/mL PCT Clinical Decision Point
| | VIDAS BRAHMS PCT | | |
| --- | --- | --- | --- |
| LIAISON BRAHMS PCT II GEN | ≤0.25 ng/mL | >0.25 ng/mL | TOTAL |
| ≤0.25 ng/mL | 158 | 3 | 161 |
| >0.25 ng/mL | 17 | 191 | 208 |
| TOTAL | 175 | 194 | 369 |
Negative percent agreement 90.3% (85.0 - 93.8%)
Positive percent agreement 98.5% (95.6 - 99.4%)
Overall: 94.6% (91.8 - 96.5%)
Table 17: % Agreement - 0.50 ng/mL PCT Clinical Decision Point
| | VIDAS BRAHMS PCT | | |
| --- | --- | --- | --- |
| LIAISON BRAHMS PCT II GEN | ≤0.50 ng/mL | >0.50 ng/mL | TOTAL |
| ≤0.50 ng/mL | 203 | 1 | 204 |
| >0.50 ng/mL | 12 | 153 | 165 |
| TOTAL | 215 | 154 | 369 |
Negative percent agreement 94.4% (90.5 - 96.8%)
Positive percent agreement 99.4% (96.5 - 99.8%)
Overall: 96.5% (94.1 - 97.9%)
Table 18: % Agreement - 2.0 ng/mL PCT Clinical Decision Point
| | VIDAS BRAHMS PCT | | |
| --- | --- | --- | --- |
| LIAISON BRAHMS PCT II GEN | ≤ 2.0 ng/mL | > 2.0 ng/mL | TOTAL |
| ≤ 2.0 ng/mL | 266 | 0 | 266 |
| > 2.0 ng/mL | 3 | 100 | 103 |
| TOTAL | 269 | 100 | 369 |
Negative percent agreement 98.9% (96.8- 99.6%)
Positive percent agreement 100% (96.4 - 100.0%)
Overall: 99.2% (97.7- 99.7%)
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Table 19: Agreement - Sample Number for All Clinical Decision Points
| | VIDAS BRAHMS PCT | | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| LIAISON BRAHMS PCT IIGEN | ≤0.10 ng/mL | >0.10 and ≤ 0.25 ng/mL | >0.25 and < 0.50 ng/mL | ≥0.50 and < 2.0 ng/mL | ≥2.0 ng/mL | TOTAL |
| ≤0.10 ng/mL | 108 | 2 | 0 | 0 | 0 | 110 |
| >0.10 and ≤ 0.25 ng/mL | 17 | 31 | 3 | 0 | 0 | 51 |
| >0.25 and < 0.50 ng/mL | 0 | 15 | 27 | 1 | 0 | 43 |
| ≥0.50 and < 2.0 ng/mL | 0 | 2 | 10 | 50 | 0 | 62 |
| ≥2.0 ng/mL | 0 | 0 | 0 | 3 | 100 | 103 |
| TOTAL | 125 | 50 | 40 | 54 | 100 | 369 |
3. Clinical Cut-off:
See assay cut-off M.1.j above.
4. Expected Values/Reference Range:
In a population of 120 self-reported healthy individuals, the 95th percentile, upper reference range limit was calculated at 0.08 ng/mL.
| Age Range | N | Ethnicity | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | African American | Asian | Caucasian | Hispanic | Other |
| <60 | 117 | 46 | 0 | 34 | 36 | 1 |
| ≥60 | 3 | 0 | 0 | 3 | 0 | 0 |
N. Instrument Name:
The LIAISON Analyzer (Model 15970)
O. System Descriptions:
1. Modes of Operation:
See Device Description (Section I) above
2. Software
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FDA has reviewed applicant’s Hazard Analysis and software development processes for this line of product types:
Yes ☐ X or No ☐
2. Specimen Identification:
A barcode reader reads the barcodes on each tube for positive identification.
4. Specimen Sampling and Handling:
See Sample Stability (M.1.k) above.
5. Calibration:
LIAISON BRAHMS PCT II GEN assay generates a continuous response (relative light units, RLU) which is used in sample grading to provide a reportable quantitative result.
Sample grading is based on the use of a calibration curve referenced to an ‘In-house’ Recombinant Human PCT standard preparation and controlled by the use of two lyophilized calibrators (Calibrator A and Calibrator B) provided in the kit together with the Reagent Integral.
The calibrators are assayed by the user to transform the kit lot specific Master Curve into a Working Curve. The Master Curves are stored on the LIAISON Analyzer and specifically matched to the kit in use via the instructions encoded in the bar codes printed on the Reagent Integral label. Each Master Curve is generated by a mathematical elaboration of the data resulting from multiple testing (at least ten runs) of an internal Reference Calibration Curve. During user calibration, the Calibrator results are used to create a Working Curve by mathematical adjustment of the Master Curve. The Working Curve is then used to calculate sample results.
The analyzer is calibrated in triplicate whenever at least one of the following conditions occurs (see LIAISON Analyzer Operator’s manual):
- A new lot of Reagent Integral or a new lot of Starter Kit is used.
- The previous calibration was performed more than eight weeks before.
- The analyzer has been serviced.
- Control values lie outside the expected ranges.
6. Quality Control:
See “Traceability, Stability, Expected Values (controls, calibrators, or methods)” Section (M.1.d) above.
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P. Other Supportive Instrument Performance Characteristics Data Not Covered In the "Performance Characteristics" Section above:
N/A
Q. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Parts 801 and 809 and the specials controls for this device type under 21CFR 866.3215.
R. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
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