LIAISON XL MUREX Anti-HBc, LIAISON MUREX Control Anti-HBc
Device Facts
| Record ID | P180038 |
|---|---|
| Device Name | LIAISON XL MUREX Anti-HBc, LIAISON MUREX Control Anti-HBc |
| Applicant | DiaSorin, Inc. |
| Product Code | SEI · Microbiology |
| Decision Date | Jan 2, 2020 |
| Decision | APRL |
| Regulation | 21 CFR 866.3173 |
| Device Class | Class 2 |
| Attributes | Pediatric |
Intended Use
The LIAISON XL MUREX Anti-HBc assay is an in vitro chemiluminescent immunoassay (CLIA) for the qualitative detection of IgG and IgM (total) antibodies to hepatitis B core antigen (anti-HBc) in human adult and pediatric (2 – 21 years) serum and plasma (lithium and sodium heparin, sodium citrate and K₂ EDTA), including separator tubes, on the LIAISON XL Analyzer. Assay results in conjunction with other laboratory results and clinical information may be used as an aid in the diagnosis of hepatitis B virus (HBV) infection in patients with symptoms of hepatitis or who may be at risk for HBV infection. The assay is not intended for use in screening blood, plasma, or tissue donors. The LIAISON XL MUREX Control Anti-HBc (negative and positive) is intended for use as assayed quality control samples to monitor the performance of the LIAISON XL MUREX Anti-HBc assay. The performance characteristics of LIAISON XL MUREX Control Anti-HBc have not been established for any other assays or instrument platforms.
Device Story
LIAISON XL MUREX Anti-HBc is a two-step competitive chemiluminescent immunoassay (CLIA) performed on the automated LIAISON XL Analyzer. Input: human serum or plasma samples. Principle: anti-HBc in sample competes with limited antigen on magnetic particles; isoluminol-antibody conjugate binds remaining epitopes. Output: light signal (relative light units, RLU) measured by photomultiplier, inversely proportional to anti-HBc concentration. Used in clinical laboratories; operated by technicians. Results interpreted by analyzer software against established cut-off (Index 1.00). Clinicians use results alongside other laboratory/clinical data to diagnose HBV infection; aids in patient management decisions regarding antiviral treatment. Benefits include accurate diagnosis of current/prior HBV infection, potentially reducing disease burden and transmission.
Clinical Evidence
Clinical agreement study evaluated 3,082 samples (prospective and retrospective) from 6 countries against 6 FDA-approved reference assays. Primary endpoints: positive and negative percent agreement (PPA/NPA) across HBV infection stages. Overall PPA 97.4% (95% CI: 95.8-98.5%) and NPA 98.4% (95% CI: 97.9-98.9%). Pediatric performance confirmed via 30-sample equivalency study and clinical agreement data. No adverse events reported in clinical study.
Technological Characteristics
Competitive CLIA; magnetic particles coated with recombinant HBcAg (E. coli); isoluminol-antibody conjugate; chemiluminescent detection. Requires LIAISON XL Analyzer, LIAISON Wash/System Liquid, and LIAISON XL Starter Kit (NaOH/H2O2). Compatible with serum, lithium/sodium heparin, sodium citrate, and K2 EDTA plasma. Refrigerated storage (2-8°C).
Indications for Use
Indicated for qualitative detection of total anti-HBc (IgG and IgM) in human serum and plasma to aid in diagnosis of HBV infection in adult and pediatric (2-21 years) patients with hepatitis symptoms or risk factors. Not for blood, plasma, or tissue donor screening.
Regulatory Classification
Identification
A hepatitis B virus (HBV) antibody assay is identified as an in vitro diagnostic device intended for prescription use in the detection of antibodies to HBV in human serum, plasma, or other matrices, and as a device that aids in the diagnosis of HBV infection in persons with signs and symptoms of hepatitis and in persons at risk for hepatitis B infection. Results from assays may be qualitative or quantitative, such as quantitative anti-HBs. In addition, results from an anti-HBc IgM (IgM antibodies to core antigen) assay indicating the presence of anti-HBc IgM are indicative of recent HBV infection. Anti-HBs (antibodies to surface antigen) assay results may be used as an aid in the determination of susceptibility to HBV infection in individuals prior to or following HBV vaccination or when vaccination status is unknown. The assay is not intended for screening of blood, plasma, cells, or tissue donors. The assay is intended as an aid in diagnosis in conjunction with clinical findings and other diagnostic procedures.
Special Controls
*Classification.* Class II (special controls). The special controls for this device are:(1) The labeling required under § 809.10(b) of this chapter must include: (i) A prominent statement that the assay is not intended for the screening of blood, plasma, cells, or tissue donors. (ii) A detailed explanation of the principles of operation and procedures for performing the assay. (iii) A detailed explanation of the interpretation of results. (iv) Limitations, which must be updated to reflect current clinical practice and disease presentation and management. The limitations must include statements that indicate: (A) When appropriate, performance characteristics of the assay have not been established in populations of immunocompromised or immunosuppressed patients or other special populations where assay performance may be affected. (B) Detection of HBV antibodies to a single viral antigen indicates a present or past infection with hepatitis B virus, but does not differentiate between acute, chronic, or resolved infection. (C) The specimen types for which the device has been cleared, and that use of the assay with specimen types other than those specifically cleared for this device may result in inaccurate assay results. (D) Diagnosis of hepatitis B infection should not be established on the basis of a single assay result but should be determined by a licensed healthcare professional in conjunction with the clinical presentation, history, and other diagnostic procedures. (E) A non-reactive assay result may occur early during acute infection, prior to development of a host antibody response to infection, or when analyte levels are below the limit of detection of the assay. (F) Results obtained with this assay may not be used interchangeably with results obtained with a different manufacturer's assay. (v) For devices intended for the quantitative detection of HBV antibodies (anti-HBs), in addition to the special controls listed in paragraphs (b)(1) and (2) of this section, labeling required under § 809.10(b) of this chapter must include: (A) The assay calibrators' traceability to a standardized reference material that FDA has determined is appropriate ( *e.g.,* a recognized consensus standard) and the limit of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), linearity, and precision to define the analytical measuring interval.(B) Performance results of the analytical sensitivity study testing a standardized reference material that FDA has determined is appropriate ( *e.g.,* a recognized consensus standard).(2) Design verification and validation must include the following: (i) Detailed device description, including all parts that make up the device, ancillary reagents required but not provided, an explanation of the device methodology, and design of the antigen(s) and capture antibody(ies) sequences, rationale for the selected epitope(s), degree of amino acid sequence conservation of the target, and the design and composition of all primary, secondary and subsequent standards used for calibration. (ii) Documentation and characterization ( *e.g.,* supplier, determination of identity, and stability) of all critical reagents (including description of the antigen(s) and capture antibody(ies)), and protocols for maintaining product integrity throughout its labeled shelf life.(iii) Risk analysis and management strategies, such as Failure Modes Effects Analysis and/or Hazard Analysis and Critical Control Points summaries and their impact on assay performance. (iv) Final release criteria to be used for manufactured assay lots with appropriate evidence that lots released at the extremes of the specifications will meet the identified analytical and clinical performance characteristics as well as stability. (v) Stability studies for reagents must include documentation of an assessment of real-time stability for multiple reagent lots using the indicated specimen types and must use acceptance criteria that ensure that analytical and clinical performance characteristics are met when stability is assigned based on the extremes of the acceptance range. (vi) All stability protocols, including acceptance criteria. (vii) When applicable, analytical sensitivity of the assay that is the same or better than that of other cleared or approved assays. (viii) Analytical performance studies and results for determining the limit of blank (LoB), limit of detection (LoD), cutoff, precision (reproducibility), including lot-to-lot and/or instrument-to-instrument precision, interference, cross reactivity, carryover, hook effect, seroconversion panel testing, matrix equivalency, specimen stability, reagent stability, and cross-genotype antibody detection sensitivity, when appropriate. (ix) For devices intended for the detection of antibodies for which a standardized reference material (that FDA has determined is appropriate) is available, the analytical sensitivity study and results testing the standardized reference material. Detailed documentation of that study and its results must be provided, including the study protocol, study report, testing results, and all statistical analyses. (x) For devices with associated software or instrumentation, documentation must include a detailed description of device software, including software applications and hardware-based devices that incorporate software. The detailed description must include documentation of verification, validation, and hazard analysis and risk assessment activities, including an assessment of the impact of threats and vulnerabilities on device functionality and end users/patients as part of cybersecurity review. (xi) Detailed documentation of clinical performance testing from a clinical study with an appropriate number of HBV reactive and non-reactive samples in applicable risk categories and conducted in the appropriate settings by the intended users. Performance must be analyzed relative to an FDA cleared or approved HBV antibody assay or a comparator that FDA has determined is appropriate. Additional relevant patient groups must be validated as appropriate. The samples must include prospective (sequential) samples for each identified specimen type and, as appropriate, additional characterized clinical samples. Samples must be sourced from geographically diverse areas. (3) For any HBV antibody assay intended for quantitative detection of anti-HBV antibodies, the following special controls, in addition to those special controls listed in paragraphs (b)(1) and (2) of this section, also apply: (i) Detailed documentation of the metrological calibration traceability hierarchy to a standardized reference material that FDA has determined is appropriate. (ii) Detailed documentation of the following analytical performance studies conducted, as appropriate to the technology, specimen types tested, and intended use of the device, including upper and lower limits of quantitation (UloQ and LloQ, respectively), linearity using clinical samples, and an accuracy study using the recognized international standard material.
Related Devices
- P180049 — LIAISON® XL MUREX anti-HBe, LIAISON® XL MUREX Control anti-HBe · DiaSorin, Inc. · Aug 29, 2020
- P010051 — IMMULITE 2000 XPI ANTI-HBC · Siemens Healthcare Diagnostics Products, Ltd. · Jul 24, 2002
- P180045 — LIAISON® XL MUREX HBc IgM, LIAISON® XL MUREX Control HBc IgM · DiaSorin, Inc. · Aug 29, 2020
- P180039 — LIAISON® XL MUREX Anti-HBs, LIAISON® XL MUREX Control Anti-HBs and LIAISON® XL MUREX Anti-HBs Verifiers · DiaSorin, Inc. · Feb 21, 2020
- P030024 — VITROS IMMUNODIAGNOSTIC PRODUCTS ANTI-HBC REAGENT PACK/CALIBRATOR · Ortho-Clinical Diagnostics · Mar 4, 2004
Submission Summary (Full Text)
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SUMMARY OF SAFETY AND EFFECTIVENESS DATA (SSED)
I. GENERAL INFORMATION
Device Generic Name: Total Antibody to Hepatitis B Core Antigen (Anti-HBc Total assay)
Device Trade Name: LIAISON® XL MUREX Anti-HBc
LIAISON® XL MUREX Control Anti-HBc
Device Procode: LOM
Applicant’s Name and Address: DiaSorin Inc.
1951 Northwestern Avenue
Stillwater, MN 55082
Date(s) of Panel Recommendation: None
Premarket Approval Application (PMA) Number: P180038
Date of FDA Notice of Approval: January 2, 2020
II. INDICATIONS FOR USE
The LIAISON XL MUREX Anti-HBc assay is an in vitro chemiluminescent immunoassay (CLIA) for the qualitative detection of IgG and IgM (total) antibodies to hepatitis B core antigen (anti-HBc) in human adult and pediatric (2 – 21 years) serum and plasma (lithium and sodium heparin, sodium citrate and K₂ EDTA), including separator tubes, on the LIAISON XL Analyzer. Assay results in conjunction with other laboratory results and clinical information may be used as an aid in the diagnosis of hepatitis B virus (HBV) infection in patients with symptoms of hepatitis or who may be at risk for HBV infection.
The assay is not intended for use in screening blood, plasma, or tissue donors.
The LIAISON XL MUREX Control Anti-HBc (negative and positive) is intended for use as assayed quality control samples to monitor the performance of the LIAISON XL MUREX Anti-HBc assay. The performance characteristics of LIAISON XL MUREX Control Anti-HBc have not been established for any other assays or instrument platforms.
III. CONTRAINDICATIONS
There are no known contraindications.
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IV. WARNINGS AND PRECAUTIONS
The warnings and precautions can be found in the LIAISON XL MUREX Anti-HBc labeling.
V. DEVICE DESCRIPTION
Kit Components
Reagents: The LIAISON XL MUREX Anti-HBc is an in vitro diagnostic device consisting of five (5) reagents provided in individual compartments within a plastic container called the Reagent Integral. The assay configuration allows performance of 100 tests.
The assay is comprised of the following components:
- 1 vial of Magnetic particles coated with HBcAg obtained in E. coli by the recombinant DNA technology, Bovine Serum Albumin (BSA), phosphate buffer, < 0.1% sodium azide.
- 1 vial Calibrator 1 containing Calf serum with high anti-HBc antibody levels and 0.2% ProClin 300, preservatives.
- 1 vial Calibrator 2 containing human serum without anti-HBc antibodies, 0.2% ProClin 300, preservatives, and an inert blue dye.
- 1 vial Buffer F containing Acetate buffer.
- 1 vial Conjugate containing Antibody to HBcAg (mouse monoclonal) conjugated to an isoluminol derivative, human serum, newborn calf serum, phosphate buffer, EDTA, 0.2% ProClin 300, preservatives, and an inert blue dye.
Controls: LIAISON XL MUREX Control Anti-HBc set consists of two (2) levels (positive and negative) ready to use controls. Each control solution allows at least twenty (20) tests to be performed. The control set is an additional material required to perform the test.
The controls are comprised of the following components:
- 2 vials Negative control containing Human serum without anti-HBc antibodies with 0.2% ProClin 300 and preservatives.
- 2 vials Positive control containing Human serum with anti-HBc antibodies (human), 0.2% ProClin 300 and preservatives.
In addition, the following Analyzer and accessories are required for performing the LIAISON XL MUREX Anti-HBc and LIAISON XL MUREX Control Anti-HBc:
- LIAISON XL Analyzer - an automated chemiluminescent analyzer that performs the complete sample processing steps of the chemiluminescent assay and interprets the results.
- LIAISON Wash/System Liquid (10x) - phosphate buffer solution, < 0.1% sodium azide.
- LIAISON XL Starter Kit – catalyst in 4% sodium hydroxide solution and 0.12% hydrogen peroxide solution.
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# Assay Principle
The qualitative determination of anti-HBc is a two-step competitive chemiluminescent immunoassay (CLIA). Anti-HBc present in samples, calibrators, or controls binds to a limited amount of antigen on the coated magnetic particles. The isoluminol-antibody conjugate links the unbound solid phase epitopes. After each incubation, the unbound material is removed with a wash cycle. Subsequently, the starter reagents are added, and a flash chemiluminescent 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 inversely indicative of anti-HBc concentration present in the sample.
Table 1: Interpretation of Results:
| Initial Result (s/co) | Repeat Result (s/co) | Interpretation |
| --- | --- | --- |
| ≥1.1 | N/A | Non-reactive |
| <1.1 >0.9 | 2 or 3 are <0.9 | Reactive |
| | 2 or 3 are ≥1.0 | Non-reactive |
| ≤0.9 | N/A | Reactive |
# VI. ALTERNATIVE PRACTICES AND PROCEDURES
There are several other alternatives for the detection of antibodies to hepatitis B core antigen (Anti-HBc). There are currently several FDA approved in vitro diagnostic tests commercially available for serological markers of hepatitis B virus (HBV) infection which, when used in conjunction with a patient's medical history, clinical examination and other laboratory findings, may be used as an aid in the diagnosis of HBV infection in patients with symptoms of hepatitis or who may be at risk for HBV infection. Each alternative has its own advantages and disadvantages. A patient should fully discuss these alternatives with his/her physician to select the method that best meets expectations and lifestyle.
# VII. MARKETING HISTORY
The LIAISON XL MUREX Anti-HBc assay (318130) and LIAISON XL MUREX Control Anti-HBc (318131) are essentially the same as the CE-marked LIAISON Anti-HBc assay (310130) and LIAISON Control Anti-HBc (310131) with some minor modifications to raw material manufacturing processes.
The LIAISON XL MUREX Anti-HBc assay (318130) and LIAISON XL MUREX Control Anti-HBc (318131) have not been marketed in the U.S. or any foreign country.
The CE marked LIAISON Anti-HBc and the LIAISON Control Anti-HBc have been marketed in multiple countries. These devices have not been withdrawn from the market in any country for reasons relating to safety and effectiveness.
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The table below includes a list all countries where the CE-marked versions have been marketed:
Table 2
| Australia | Switzerland | Jordan |
| --- | --- | --- |
| Austria | United Kingdom | Bahrain |
| Belgium | Colombia | Qatar |
| Brazil | Peru | Kuwait |
| China | Dominican Republic | Iraq |
| Czech | Guatemala | Greece |
| France | Panama | Russia |
| Germany | Paraguay | Cipro |
| Israel | Chile | Hungary |
| Italy | Argentina | Bulgaria |
| Mexico | Indonesia | Croatia |
| Netherlands | Pakistan | Lithuanian Republic |
| Nordic | Thailand | Romania |
| Poland | Morocco | South Africa Republic |
| Portugal | Tunisia | Turkey |
| Spain | Saudi Arabia | |
VIII. POTENTIAL ADVERSE EFFECTS OF THE DEVICE ON HEALTH
Below is a list of the potential adverse effects (e.g., complications) associated with the use of the device. The LIAISON XL MUREX Anti-HBc is intended for in vitro diagnostic use, and as a result, there is no direct adverse effect on the patient. Standard good laboratory practices are considered sufficient to minimize risks to the end user.
Failure of the product to perform as intended or human error in the use of the test may lead to a false result. Appropriate Warnings and Precautions for identified risks are contained in the labeling and assay Instructions for Use.
Risks of false positive tests includes improper patient management, including treatment for hepatitis B with antiviral medication. Antiviral medical has risks including toxicity and more rarely allergic reactions. Over time, viral resistance in patients who are co-infected but undiagnosed with other viruses using the same antiviral medication, such as HIV, can lead to viral resistance; however, the chance of an undiagnosed co-infection in a patient tested for hepatitis B is exceedingly unlikely. Additionally and likely more importantly, because hepatitis B core antibody is ordered as part of a panel in clinical practice, this risk will likely be mitigated as incongruous test results would lead a clinician to either retest the patient or further investigate the etiology of hepatitis. As the performance of the assay in the clinical trial suggests that false positive results will be uncommon, the true risk of a false negative is likely minimal.
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Risks of false negative tests include potentially missing and undertreating a patient who has hepatitis B infection and whose clinical picture warrants antiviral treatment. Again, because hepatitis B core antibody is ordered as part of a panel in clinical practice, the risk of missing and undertreating a patient who has hepatitis B infection will likely be mitigated as incongruous test results would lead a clinician to either retest the patient or further investigate the etiology of hepatitis. As the performance of the assay in the clinical trial suggests that false negative results will be uncommon, the true risk of a false negative is likely minimal.
For the specific adverse events that occurred in the clinical study, please see Section X below.
## IX. SUMMARY OF NONCLINICAL STUDIES
### A. Laboratory Studies
#### 1. Cut-off Determination
The cut-off was established internally at DiaSorin by testing at total of 111 samples (60 known negative and 51 known positive). A Receiver Operating Characteristics (ROC) analysis was performed on the results of the specimens tested. The assay’s cut-off was evaluated with the observed results to demonstrate that its selection represents the best level of specificity, without compromising the sensitivity.
The cut-off value at an Index of 1.00 is within the optimal range determined by the ROC curve to discriminate between negative and positive results.
The established cut-off Index is 1.00 with an equivocal range of $\pm 10\%$ (0.9 - 1.1).
#### 2. Sensitivity / Seroconversion Panels
The seroconversion sensitivity of the LIAISON XL MUREX Anti-HBc assay has been demonstrated by testing 9 commercial seroconversion panels in comparison to a reference anti-HBc immunoassay in terms of number of days from initial draw to first positive sample, as well as the difference between the last non-reactive results and the first reactive results.
The LIAISON XL MUREX Anti-HBc assay yielded a reactive result sooner by one blood draw or more than the comparator assay in 5 panels, a reactive result in the same blood draw as the comparator assay in 3 panels and yielded a reactive result one blood draw later than the comparator method in one panel.
#### 3. Analytical Sensitivity / Dilution Study with Standard
The sensitivity of the LIAISON XL MUREX Anti-HBc assay was evaluated by preparing serial dilutions of the HBc Reference Material 82 (IgG anti-HBc, Paul-
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Ehrlich-Institute Germany) in serum and EDTA plasma negative for Anti-HBc. Dilutions were tested in triplicate on 3 different kit lots and on four (4) LIAISON XL Analyzers. The maximum dose (PEI U/mL) for all 3 kit lots were 0.571, 0.563 and 0.574.
## 4. Endogenous Interference
Potential interference of high levels of endogenous substances including Triglycerides (3000 mg/dL), Hemoglobin (1000 mg/dL), Bilirubin (conjugated and unconjugated 20 mg/dL), Albumin (6000 mg/dL) and Cholesterol (350 mg/dL) were evaluated. Ten (10) negative samples or negative pools were spiked with an IgG anti-HBc positive sample to achieve high negative and low positive samples. Samples were tested in 26 replicates each on one (1) kit lot. No interference was observed at the levels tested.
## 5. Analytical Specificity (Cross-Reactivity)
A study was conducted to evaluate the LIAISON XL MUREX Anti-HBc assay for cross-reactivity with specimens from individuals with medical conditions unrelated to HBV infection. A total of 304 samples from 28 unrelated medical conditions were tested in singlicate on one (1) kit lot of LIAISON XL MUREX Anti-HBc and on a reference Anti-HBc assay.
Of the 304 samples, no evidence of cross-reactivity was observed. The results of each potential cross-reactant are shown in in table below.
Table 3: Summary of Cross-Reactivity Testing
| | | N° of observed negative results | |
| --- | --- | --- | --- |
| Potential cross reactant (nature of samples to be clarified) | N° of expected negative samples | LIAISON XL MUREX Anti HBc | Reference Method |
| Anti-nuclear antibodies (ANA) | 10 | 10 | 10 |
| Auto-immune hepatitis | 10 | 10 | 10 |
| C. trachomatis | 11 | 11 | 11 |
| CMV (IgG / IgM) | 11 | 11 | 11 |
| EBV (IgM) | 11 | 11 | 11 |
| Fatty liver disease | 11 | 11 | 11 |
| HAMA | 11 | 11 | 11 |
| Hemodialysis patient | 11 | 11 | 11 |
| Hepatitis A Virus (anti-HAV IgM) | 11 | 11 | 11 |
| Hepatitis C Virus (anti-HCV) | 11 | 11 | 11 |
| Hepatocellular carcinoma | 11 | 11 | 11 |
| HIV-1 (anti-HIV-1) | 11 | 11 | 11 |
| HIV-2 (anti-HIV-2) | 11 | 11 | 11 |
| HSV (IgG / IgM) | 11 | 11 | 11 |
| HTLV-1/2 (anti-HTLV) | 11 | 11 | 11 |
| IgG monoclonal gammopathy | 11 | 11 | 11 |
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| | | N° of observed negative results | |
| --- | --- | --- | --- |
| Potential cross reactant (nature of samples to be clarified) | N° of expected negative samples | LIAISON XL MUREX Anti HBc | Reference Method |
| IgM monoclonal gammopathy | 10 | 10 | 10 |
| Influenza vaccine recipients | 11 | 11 | 11 |
| Multiparous pregnancies | 11 | 11 | 11 |
| Multiple myeloma | 11 | 11 | 11 |
| Multiple transfusion recipients | 11 | 11 | 11 |
| N. gonorrhoea | 11 | 11 | 11 |
| Pregnancy 1st trimester | 11 | 11 | 11 |
| Pregnancy 2nd trimester | 10 | 10 | 10 |
| Pregnancy 3rd trimester | 11 | 11 | 11 |
| Rheumatoid Factor | 11 | 11 | 11 |
| T. pallidum | 11 | 11 | 11 |
| T.cruzi (anti-T. cruzi) | 11 | 11 | 11 |
# 6. Sample Equivalence/Matrix Effect
Twenty-five (25) paired sets of matched serum (with and without gel SST) and plasma (lithium and sodium heparin, sodium citrate and $\mathrm{K}_2\mathrm{EDTA}$ ) were tested to determine if these sample types provide equivalent results on the LIAISON XL MUREX Anti-HBc assay. Each sample was divided into three aliquots. Two sets of aliquots were spiked with an anti-HBc high positive sample to achieve two (2) levels of samples: high negative and low positive samples. The third set of aliquots was un-spiked to serve as control samples. The results of the negative and low positive samples did not change the classification of the expected result. The results obtained on the serum-plasma paired samples indicate that there is equivalence among serum (with and without Gel SST), $\mathrm{K}_2$ -EDTA, Lithium Heparin and Sodium Heparin plasma. However, the data show that plasma samples collected in Sodium Citrate can lead to lower Index values (approximately $10\%$ ) in comparison to normal serum. The LIAISON XL MUREX Anti-HBc assay package insert notes:
Specimens collected in sodium citrate may yield lower Index values (about $10\%$ ) in comparison to normal serum which may cause an increased likelihood of false negative results.
# 7. Carry-Over Study
The LIAISON XL Analyzer uses disposable tips for sample pipetting. A carry-over study was performed to evaluate the extent of carryover and the associated residual risk for signal carryover in the instrument's measuring cell as the result of a high signal-generating sample.
Two samples were used for this evaluation: one (1) anti-HBc negative human serum sample and one (1) human positive sample/pool with a high level of anti-HBc analyte.
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The samples were tested in singlicate in five (5) runs in the following sequence: High Pos, Neg, High Pos, Neg, High Pos, Neg, High Pos, Neg, High Pos, Neg.
All acceptance criteria were met, demonstrating that no significant amount of analyte is carried over from one sample reaction into the subsequent sample reactions.
## 8. Stability Studies
### Sample Stability
Studies were performed to determine the storage stability of patient serum and plasma samples at storage temperatures of 2-8°C, room temperature (RT), -20 °C. A multiple freeze/thaw (F/T) study was also performed.
Serum and plasma samples tested contained Anti-HBc analyte levels of negative, high negative and low positive.
- 2-8 °C study – samples were tested unstressed (T=0), and again after 1, 2, 3, 4, 5, 7 and 8 days of storage at 2-8°C for 24 hours per day.
- room temperature study (RT) – samples were tested immediately after preparation and again after 1, 2, 3, 4, and 5 days of storage at RT for 24 hours each day.
- -20 °C study – samples were tested unstressed (T=0) and stored at -20 °C or lower for 1, 3, and 4 months.
- Freeze/Thaw (F/T) study – samples were tested unstressed (T=0) and after 1, 2, 3, 4, 5, 6, and 7 F/T cycles. Samples were frozen for 12-24 hours at -20°C or lower and thawed at room temperature.
The results of the studies indicate serum and plasma samples are stable for:
- 4 days at 2-8°C
- 4 days at room temperature
- 3 months at -20°C
- 3 Freeze/Thaw cycles.
### Reagent Stability
#### Real-Time (Shelf-Life)
Studies were performed to establish the shelf-life for the LIAISON XL MUREX Anti-HBc assay. Three (3) lots of LIAISON XL MUREX Anti-HBc were stored at the recommended storage temperature of 2-8°C throughout the study. Performance was assessed against clinically relevant acceptance criteria using three (3) lots LIAISON XL MUREX Control Anti-HBc (positive and negative) and an internal stability panel consisting of eight (8) samples. Study results demonstrate that reagents are stable and continue to meet acceptance criteria eighteen (18) months after the date of manufacture for the LIAISON XL MUREX Anti-HBc.
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## Reagent On-Board
Stability studies were conducted to determine the length of time the LIAISON XL MUREX Anti-HBc Reagent Integral can be stored on-board the LIAISON XL Analyzer in the refrigerated area once opened.
One (1) lot of the LIAISON XL MUREX Anti-HBc assay was stored on-board the LIAISON XL Analyzer throughout the 13 weeks of the study. The LIAISON XL MUREX Control Anti-HBc (negative and positive) along with the internal stability panel were tested in duplicate at one (1) week intervals up to the 13 weeks.
The LIAISON XL MUREX Anti-HBc assay is stable on-board the LIAISON XL Analyzer for 12 weeks.
## Reagent Open Use
The aim of this study was to assess the open use stability of the LIAISON XL MUREX Anti-HBc kit reagents by simulating normal conditions of use as specified in the instruction for use.
Testing of samples was performed in duplicate, on one (1) lot of LIAISON XL MUREX Anti-HBc and one (1) lot of LIAISON XL MUREX Control Anti-HBc. Results were calculated using the initial (time zero) assay calibration.
The opened Reagent Integral was then removed from the XL Analyzer and stored at 2-8 °C. Kit performance using the opened Reagent Integral was evaluated weekly up to 13 weeks.
The Reagent Integral is stable after opening for 12 weeks when stored at 2-8 °C.
## Temperature Stress/Reagent Transport Study
The transport simulation tests were performed in order to verify that kit reagents maintain their properties during the shipment and delivery conditions to the customer. After being subjected to simulated stress conditions, testing was performed on 1 lot of LIAISON XL MUREX Anti-HBc at midlife and will be tested at expiration.
All testing performed meets acceptance criteria under various simulated transport conditions.
## Calibrator Stability
The LIAISON XL MUREX Anti-HBc calibrators are included on the Reagent Integral. All studies for the Reagent Integral are applicable to the 2 levels of calibrators provided.
## Calibration Interval Stability
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The aim of this study was to assess stability of the product calibration by simulating normal condition of use as specified in the instruction for use.
A calibration was performed at time 0 and the Reagent Integral was stored on board the analyzer for the duration of the study. Kit performance was evaluated weekly up to nine (9) weeks by testing the stability panel and LIAISON XL MUREX Control Anti-HBc on one (1) lot of LIAISON XL MUREX Anti-HBc reagents. Results were generated using the initial (time zero) assay calibration and performance was assessed against clinically relevant acceptance criteria.
Results demonstrate that the LIAISON XL MUREX Anti-HBc calibration is stable for eight (8) weeks.
## Control stability
### Real-time (Shelf-Life)
Studies were performed to establish the shelf-life for the LIAISON XL MUREX Control Anti-HBc. Three lots of LIAISON XL MUREX Control Anti-HBc were stored at the recommended storage temperature of 2-8°C throughout the study. Current results demonstrate that the positive and negative controls are stable and continue to meet acceptance criteria at eighteen (18) months.
### Open use
The aim of this study was to assess stability of the opened Control vials by simulating normal conditions of use, as specified in the instruction for use. Testing was performed in duplicate, on one lot of LIAISON XL MUREX Control Anti-HBc.
LIAISON XL MUREX Control Anti-HBc (negative and positive) were within their established ranges and were assessed against clinically relevant acceptance criteria.
The LIAISON XL MUREX Control Anti-HBc (negative and positive) are stable for 12 weeks after opening when stored at 2-8 °C between uses.
### Temperature Stress/Reagent Transport Study
The transport simulation tests were performed in order to ensure that kit Controls maintain their properties during the shipment and delivery conditions to the customer. After being subjected to simulated stress conditions testing was performed on 1 lot of LIAISON XL MUREX Control Anti-HBc.
All testing performed meets acceptance criteria under various simulated transport conditions.
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9. Precision
Internal 20 Days
A precision/reproducibility study was carried out over a period of twenty (20) days on the LIAISON XL MUREX Anti-HBc assay using the LIAISON XL Analyzer. The CLSI document EP05-A3 was consulted in the preparation of the testing protocol. The testing was performed internally at DiaSorin S.p.A.
A coded panel of ten (10) serum samples consisting of 1 Negative, 3 High Negative, 3 Low Positive, and 3 Moderate Positive and 3 lots of the LIAISON XL MUREX Control Anti-HBc (neg and pos) were tested in 2 replicates per run, 2 runs per day for 20 days using 3 different LIAISON XL MUREX Anti-HBc assay reagents and spanning at least 2 calibration cycles.
The Repeatability of the combined 3 lots of LIAISON XL MUREX Anti-HBc ranged from 1.4% to 2.3%. The with-in Laboratory %CV of the combined 3 lots of LIAISON XL MUREX Anti-HBc ranged from 4.2% to 12.9%. The results are shown below.
Table 4: Summary of Precision Study
| Sample ID | N | Mean | Repeatability (within-run) | | Between Run | | Between Day | | Between Lot | | Within Laboratory | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Ctrl Neg #RS-672 | 240 | *156933 | 2455 | 1.6% | 4303 | 2.7% | 3288 | 2.1% | 4868 | 3.1% | 7684 | 4.9% |
| Ctrl Neg #RS-673 | 240 | *155995 | 2351 | 1.5% | 4801 | 3.1% | 886 | 0.6% | 4729 | 3.0% | 7192 | 4.6% |
| Ctrl Neg #RS-674 | 240 | *155885 | 2161 | 1.4% | 4524 | 2.9% | 2073 | 1.3% | 4378 | 2.8% | 6972 | 4.5% |
| Ctrl Pos #RS-675 | 240 | 0.368 | 0.007 | 1.9% | 0.014 | 3.8% | 0.012 | 3.2% | 0.029 | 7.8% | 0.035 | 9.5% |
| Ctrl Pos #RS-676 | 240 | 0.369 | 0.006 | 1.6% | 0.016 | 4.3% | 0.011 | 3.0% | 0.029 | 7.8% | 0.035 | 9.5% |
| Ctrl Pos #RS-677 | 240 | 0.389 | 0.007 | 1.8% | 0.018 | 4.7% | 0.015 | 3.8% | 0.036 | 9.3% | 0.044 | 11.2% |
| AHBC-1-U1 | 240 | 2.31 | 0.032 | 1.4% | 0.062 | 2.7% | 0.053 | 2.3% | 0.04 | 1.7% | 0.097 | 4.2% |
| AHBC-1-U2 | 240 | 1.50 | 0.031 | 2.1% | 0.075 | 5.0% | 0.042 | 2.8% | 0.08 | 5.3% | 0.122 | 8.1% |
| AHBC-1-U3 | 240 | 1.58 | 0.036 | 2.3% | 0.076 | 4.8% | 0.047 | 3.0% | 0.079 | 5.0% | 0.125 | 7.9% |
| AHBC-1-U4 | 240 | 1.46 | 0.033 | 2.2% | 0.073 | 5.0% | 0.047 | 3.2% | 0.084 | 5.8% | 0.125 | 8.6% |
| AHBC-1-U5 | 240 | 0.754 | 0.016 | 2.1% | 0.033 | 4.3% | 0.024 | 3.2% | 0.054 | 7.2% | 0.07 | 9.2% |
| AHBC-1-U6 | 240 | 0.773 | 0.017 | 2.2% | 0.037 | 4.8% | 0.029 | 3.8% | 0.063 | 8.2% | 0.081 | 10.4% |
| AHBC-1-U7 | 240 | 0.586 | 0.013 | 2.2% | 0.031 | 5.3% | 0.018 | 3.1% | 0.044 | 7.5% | 0.058 | 10.0% |
| AHBC-1-U8 | 240 | 0.174 | 0.003 | 1.9% | 0.008 | 4.6% | 0.005 | 2.9% | 0.02 | 11.5% | 0.022 | 12.9% |
| AHBC-1-U9 | 240 | 0.237 | 0.004 | 1.5% | 0.007 | 2.9% | 0.005 | 2.3% | 0.015 | 6.3% | 0.018 | 7.4% |
| AHBC-1-U10 | 240 | 0.262 | 0.005 | 1.8% | 0.007 | 2.8% | 0.005 | 1.8% | 0.017 | 6.5% | 0.02 | 7.5% |
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# External Precision 5-day Study
A five (5) day precision/reproducibility study was conducted at two (2) external laboratories and at DiaSorin Inc. to verify the precision of the LIAISON® XL MUREX Anti-HBc assay. The CLSI document EP15-A3 was consulted in the preparation of the testing protocol. The coded panel, comprised of ten (10) frozen serum samples was the same panel used in the 20-day precision study.
The precision panel was tested at all three (3) sites on the LIAISON® XL Analyzer using six (6) replicates per run in one (1) run per day for five (5) operating days with multiple technicians performing the testing.
Table 5: Summary of Reproducibility Study
| Sample ID | N | Mean | Repeatability (within-run) | | Between Days/Runs | | Within Laboratory | | Between Sites/Lots | | Reproducibility | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Ctrl Neg (all 3 lots) | 90 | *131264 | 3373 | 2.6% | 4696 | 3.6% | 5782 | 4.4% | 3421 | 2.6% | 6718 | 5.1% |
| Ctrl Pos (all 3 lots) | 90 | 0.378 | 0.008 | 2.1% | 0.016 | 4.3% | 0.018 | 4.8% | 0.013 | 3.4% | 0.022 | 5.9% |
| AHBC-1-U1 | 90 | 2.336 | 0.045 | 1.9% | 0.092 | 3.9% | 0.103 | 4.4% | 0.092 | 4.0% | 0.138 | 5.9% |
| AHBC-1-U2 | 90 | 1.547 | 0.063 | 4.0% | 0.133 | 8.6% | 0.147 | 9.5% | 0.144 | 9.3% | 0.206 | 13.3% |
| AHBC-1-U3 | 90 | 1.624 | 0.061 | 3.8% | 0.092 | 5.7% | 0.111 | 6.8% | 0.097 | 5.9% | 0.147 | 9.0% |
| AHBC-1-U4 | 90 | 1.464 | 0.060 | 4.1% | 0.084 | 5.8% | 0.104 | 7.1% | 0.126 | 8.6% | 0.163 | 11.2% |
| AHBC-1-U5 | 90 | 0.769 | 0.031 | 4.0% | 0.049 | 6.4% | 0.058 | 7.6% | 0.044 | 5.7% | 0.073 | 9.5% |
| AHBC-1-U6 | 90 | 0.807 | 0.036 | 4.4% | 0.063 | 7.8% | 0.072 | 8.9% | 0.025 | 3.1% | 0.076 | 9.5% |
| AHBC-1-U7 | 84 | 0.595 | 0.023 | 3.8% | 0.04 | 6.7% | 0.046 | 7.7% | 0.022 | 3.7% | 0.051 | 8.6% |
| AHBC-1-U8 | 90 | 0.184 | 0.007 | 3.8% | 0.018 | 9.8% | 0.019 | 10.5% | 0.016 | 8.9% | 0.025 | 13.8% |
| AHBC-1-U9 | 90 | 0.241 | 0.005 | 2.1% | 0.009 | 3.6% | 0.010 | 4.2% | 0.016 | 6.7% | 0.019 | 7.9% |
| AHBC-1-U10 | 90 | 0.260 | 0.007 | 2.7% | 0.004 | 1.6% | 0.008 | 3.1% | 0.011 | 4.1% | 0.013 | 5.2% |
# 10. Pediatric and Adult Sample Equivalency
Pediatric samples were tested to determine if these types of samples provide equivalent results to adult human serum.
A total of thirty (30) negative pediatric patient samples were used for this study. The pediatric samples encompassed the age range of two (2) months to twenty-one (21) years. Ten (10) pediatric samples were spiked with IgG anti-HBc high positive sample to obtain high negative samples. Ten (10) pediatric samples were spiked with IgG anti-HBc high positive sample to obtain low positive samples. Ten (10) pediatric samples were spiked with IgG anti-HBc high positive sample to obtain moderate positive samples. Adult negative pool samples were used as controls and were spiked with IgG anti-HBc high positive sample to achieve the same three (3) levels of samples: high negative, low positive and moderate positive samples.
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The samples were tested in duplicate, with the LIAISON XL MUREX Anti-HBc assay. Percent (%) recovery of the analyte from the pediatric and adult blood was calculated for each sample.
One (1) high negative pediatric sample out of the total 30 pediatric samples tested was outside the ± 10% range. All acceptance criteria were met demonstrating acceptable performance of pediatric samples. It can be concluded that pediatric samples react in the same way as the adult samples and are acceptable for use in the LIAISON® XL MUREX Anti-HBc assay.
## B. Animal Studies
Not Applicable
## C. Additional Studies
Not Applicable
## X. SUMMARY OF PRIMARY CLINICAL STUDY
The applicant performed a clinical study to establish a reasonable assurance of safety and effectiveness for the detection of antibodies to hepatitis-B core antigen with the LIAISON XL MUREX Anti-HBc using samples that would routinely be tested for hepatitis in the US. Data from this clinical study were the basis for the PMA approval decision. A summary of the clinical study is presented below.
## A. Study Design
A multi-site clinical agreement study was conducted to evaluate the clinical performance of the LIAISON XL MUREX Anti-HBc assay on samples that would routinely be tested for hepatitis and samples that were selected from individuals that were diagnosed with acute or chronic Hepatitis B infection.
The clinical agreement study involved the testing of 3,082 samples on six (6) FDA approved reference assays, each detecting a unique serological marker (HBsAg, HBeAg, Anti-HBs, Anti-HBc, Anti-HBc IgM, and Anti-HBe) in order to determine the HBV classification for each of the samples tested.
The samples were collected from 6 different countries: Russia, Colombia, Cameroon, Ghana, Nigeria, and the United States. The U.S. samples were from multiple states including Ohio, Pennsylvania, Indiana, Florida, California, Texas, New Jersey, Tennessee, Massachusetts, and Puerto Rico.
The prospective (unselected) subjects were defined as follows:
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- Pediatric and adult male (38.2%), female (61.6%) and unknown gender (0.2%) subjects at risk for hepatitis due to medical conditions (dialysis, transplantation), occupation, lifestyle, behavior or a known exposure event.
- Subjects showing signs or symptoms and individuals living in an area with a higher probability of HBV infection.
- The demographic breakdown of the prospective population was as follows: American Indian/Alaskan Native (0.1%), Asian (0.8%), Black/African American (31.2%), Caucasian (62.5%), Other (5.2%), and Unknown (0.2%) with an age range of 2 - 98 years of age.
The retrospective (selected/archived) samples were from male (69.5%), female (21.9%), and unknown gender (8.6%) subjects diagnosed with acute and/or chronic Hepatitis having an age range of 17 - 67 years of age from the following ethnicities: Asian (1.6%), Black/African American (23.8%), Caucasian (73%), other (1.2%) and 0.4% Unknown.
The distribution of LIAISON XL MUREX Anti-HBc reactive and non-reactive results by age and gender of the overall prospective population are presented below.
Table 6: Demographic Summary of the Prospective Population
| Age Range | Gender | LIAISON XL MUREX | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | + | | - | | Total |
| | | n | % | n | % | |
| 0-9 | F | 0 | 0.0% | 5 | 100.0% | 5 |
| | M | 0 | 0.0% | 10 | 100.0% | 10 |
| 10-19 | F | 0 | 0.0% | 40 | 100.0% | 40 |
| | M | 0 | 0.0% | 15 | 100.0% | 15 |
| 20-29 | F | 18 | 4.6% | 371 | 95.4% | 389 |
| | M | 18 | 7.7% | 215 | 92.3% | 233 |
| 30-39 | F | 28 | 5.9% | 446 | 94.1% | 474 |
| | M | 29 | 12.9% | 195 | 87.1% | 224 |
| 40-49 | F | 28 | 9.7% | 262 | 90.3% | 290 |
| | M | 34 | 16.9% | 167 | 83.1% | 201 |
| 50-59 | F | 36 | 15.5% | 196 | 84.5% | 232 |
| | M | 32 | 17.3% | 153 | 82.7% | 185 |
| 60-69 | F | 27 | 17.1% | 131 | 82.9% | 158 |
| | M | 21 | 19.4% | 87 | 80.6% | 108 |
| 70-79 | F | 7 | 15.2% | 39 | 84.8% | 46 |
| | M | 4 | 10.3% | 35 | 89.7% | 39 |
| 80-89 | F | 4 | 28.6% | 10 | 71.4% | 14 |
| | M | 0 | 0.0% | 7 | 100.0% | 7 |
| 90-98 | F | 0 | 0.0% | 4 | 100.0% | 4 |
| | M | 0 | N/A | 0 | N/A | 0 |
| Unk | F | 0 | 0.0% | 1 | 100.0% | 1 |
| | M | 0 | 0.0% | 1 | 100.0% | 1 |
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| Age Range | Gender | LIAISON XL MUREX | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | + | | - | | Total |
| | | n | % | n | % | |
| Total | | 286 | 10.7% | 2390 | 89.3% | 2676 |
## Hepatitis B Status Classification
Hepatitis B Status Classification was based on testing all the samples with FDA approved HBV assays for HBsAg, HBeAg, Anti-HBc, Anti-HBc IgM, Anti-HBe and Anti-HBs. HBV classification for the prospective and retrospective specimens is presented below.
Table 7: Hepatitis B Status Classification
| HBV Classification | HBsAg | HBeAg | Total Anti-HBc | Anti-HBc IgM | Anti-HBe | Anti-HBs | Prospective (n) | Retrospective (n) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Acute | R | NR | NR | NR | NR | NR | 12 | 97 |
| Acute | R | R | NR | NR | NR | NR |
| Acute | R | R | R | R | NR | NR |
| Acute | R | R | R | R | R | NR |
| Acute | R | R | R | R | EQV | NR |
| Acute | R | NR | R | EQV | R | NR |
| Acute | R | NR | R | R | EQV | NR |
| Acute | R | EQV | R | R | R | NR |
| Acute | R | NR | R | R | NR | NR |
| Acute | R | R | R | R | NR | R |
| Acute | R | R | R | R | R | R |
| Acute | R | R | R | R | R | R |
| Late Acute | R | NR | R | R | R | NR | 2 | 32 |
| Late Acute | R | NR | R | R | R | R |
| Chronic | R | NR | NR | NR | R | NR | 76 | 68 |
| Chronic | R | NR | R | NR | NR | R |
| Chronic | R | R | R | NR | NR | R |
| Chronic | R | R | R | NR | NR | NR |
| Chronic | R | R | R | NR | R | NR |
| Chronic | R | R | R | NR | R | NR |
| Chronic | R | R | R | R | R | R |
| Chronic | R | R | R | R | R | R |
| C | R | R | R | R | R | R |
| Early Recovery | NR | NR | R | R | R | NR | 48 | 9 |
| Early Recovery | NR | NR | R | EQV | R | R |
| Early Recovery | NR | NR | R | R | NR | NR |
| Early Recovery | NR | NR | R | NR | R | NR |
| Early Recovery | NR | NR | R | NR | NR | NR |
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| HBV Classification | HBsAg | HBeAg | Total Anti-HBc | Anti-HBc IgM | Anti-HBe | Anti-HBs | Prospective (n) | Retrospective (n) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Early Recovery | NR | NR | R | R | NR | R | | |
| Early Recovery | NR | NR | R | R | R | R | | |
| Recovery | NR | NR | R | NR | R | R | 131 | 36 |
| Recovery | NR | NR | NR | NR | R | R | | |
| Recovery | NR | NR | R | NR | EQV | R | | |
| Immune Due to Natural Infection | NR | NR | R | NR | NR | R | 104 | 3 |
| Immune Due to Natural Infection | NR | NR | R | NR | NR | EQV | | |
| HBV Vaccine Response | NR | NR | NR | NR | NR | R | 1144 | 8 |
| HBV Vaccine Response | NR | NR | NR | NR | NR | EQV | | |
| Not Previously Infected | NR | NR | NR | NR | NR | NR | 1302 | 1 |
| Not Interpretable | NR | NR | NR | NR | R | NR | 7 | 2 |
| Not Interpretable | NR | NR | NR | R | NR | NR | | |
| Not Interpretable | NR | R | NR | NR | NR | NR | | |
| Not Interpretable | NR | R | NR | NR | NR | R | | |
| Not Interpretable | NR | R | R | R | NR | EQV | | |
| Not Interpretable | NR | R | R | R | NR | R | | |
| Not Interpretable | R | NR | NR | NR | NR | R | | |
| Total | | | | | | 2826 | 256 | |
# Clinical Agreement Study Analysis
Comparison results of the LIAISON XL MUREX Anti-HBc to the reference anti-HBc assay are presented with Negative and Positive percent (\%) agreement and $95\%$ confidence intervals for combined prospective and retrospective specimens for each of the HBV Classification categories. In addition, Pediatric Cumulative (prospective and retrospective) Clinical Agreement results are presented below.
Table 8: Cumulative Clinical Agreement (Combined Prospective & Retrospective)
| HBV Classification | Reference Anti-HBc assay | | | | Total |
| --- | --- | --- | --- | --- | --- |
| | Reactive | | Non-reactive | | |
| | LIAISON® XL MUREX Anti-HBc | | LIAISON® XL MUREX Anti-HBc | | |
| | Reactive | Non-reactive | Reactive | Non-reactive | |
| Acute | 100 | 0 | 2 | 7 | 109 |
| Late Acute | 34 | 0 | 0 | 0 | 34 |
| Chronic | 142 | 2 | 0 | 0 | 144 |
| Early Recovery | 52 | 5 | 0 | 0 | 57 |
| Recovery | 162 | 1 | 1 | 3 | 167 |
| Immune Due to Natural Infection | 99 | 8 | 0 | 0 | 107 |
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| HBV Vaccine Response | 1 | 0 | 30 | 1121 | 1152 |
| --- | --- | --- | --- | --- | --- |
| Not Previously Infected | 0 | 0 | 6 | 1297 | 1303 |
| Not Interpretable | 2 | 0 | 0 | 7 | 9 |
| Total | 592 | 16 | 39 | 2435 | 3082 |
Table 9: Cumulative Clinical Agreement (Combined Prospective & Retrospective)
| HBV Classification | Positive Percent Agreement (PPA) | Negative Percent Agreement (NPA) |
| --- | --- | --- |
| Acute | 100/100 (100.0%)
95% CI: 96.3% to 100.0% | 7/9 (77.8%)
95% CI: 45.3% to 93.7% |
| Late Acute | 34/34 (100.0%)
95% CI: 89.8% to 100.0% | N/A |
| Chronic | 142/144 (98.6%)
95% CI: 95.1% to 99.6% | N/A |
| Early Recovery | 52/57 (91.2%)
95% CI: 81.1% to 96.2% | N/A |
| Recovery | 162/163 (99.4%)
95% CI: 96.6% to 99.9% | 3/4 (75.0%)
95% CI: 300.1% to 95.4% |
| Immune Due to Natural Infection | 99/107 (92.5%)
95% CI: 85.9% to 96.2% | N/A |
| HBV Vaccine Response | 1/1 (100.0%)
95% CI: 20.7% to 100.0% | 1121/1151 (97.4%)
95% CI: 96.3% to 98.2% |
| Not Previously Infected | N/A | 1297/1303 (99.5%)
95% CI: 99.0% to 99.8% |
| Not Interpretable | 2/2 (100.0%)
95% CI: 34.2% to 100.0% | 7/7 (100.0%)
95% CI: 64.6% to 100.0% |
## Clinical Endpoints
With regard to safety, as an *in vitro* diagnostic test, the LIAISON XL MUREX Anti-HBc test involves taking a sample of plasma or serum from a patient. The test, therefore, presents no more safety hazard to an individual being tested than other tests where blood samples are drawn. Safety issues regarding false positive and negative test results are discussed in section VIII.
With regard to effectiveness, the clinical performance of the LIAISON XL MUREX Anti-HBc was evaluated versus a FDA approved anti-HBc test for patients at risk for infection with hepatitis B and for patients with signs and symptoms of hepatitis.
With regard to success/failure criteria, the assay performed well with a positive percent agreement of 97.4% among subjects in various stages of HBV infection, a negative percent agreement (NPA) of 97.4% in HBV-vaccinated subjects, and an NPA of 99.8% among subjects not previously infected with HBV.
## B. Accountability of PMA Cohort
The clinical agreement study involved the testing of 3,082 samples on six (6) FDA approved reference assays, each detecting a unique serological marker (HBsAg, HBeAg, Anti-HBs,
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Anti-HBc, Anti-HBc IgM, and Anti-HBe in order determine the HBV classification for each of the samples tested.
The samples were collected from 6 different countries: Russia, Colombia, Cameroon, Ghana, Nigeria, and the United States. The U.S. samples were from multiple states including Ohio, Pennsylvania, Indiana, Florida, California, Texas, New Jersey, Tennessee, Massachusetts, and Puerto Rico.
## C. Study Population Demographics and Baseline Parameters
The demographics of the study population are typical for an anti-HBc detection study performed in the US.
The prospective (unselected) subjects were defined as follows:
- Pediatric and adult male (38.2%), female (61.6%) and unknown gender (0.2%) subjects at risk for hepatitis due to medical conditions (dialysis, transplantation), occupation, lifestyle, behavior or a known exposure event.
- Subjects showing signs or symptoms and individuals living in an area with a higher probability of HBV infection.
- The demographic breakdown of the prospective population was as follows: American Indian/Alaskan Native (0.1%), Asian (0.8%), Black/African American (31.2%), Caucasian (62.5%), Other (5.2%), and Unknown (0.2%) with an age range of 2 - 98 years of age.
The retrospective (selected/archived) samples were from male (69.5%), female (21.9%), and unknown gender (8.6%) subjects diagnosed with Acute and/or Chronic Hepatitis having an age range of 17 - 67 years of age from the following ethnicities: Asian (1.6%), Black/African American (23.8%), Caucasian (73%), other (1.2%) and 0.4% Unknown. The table below shows the demographic distribution of the cohort.
Table 10: Retrospective Demographic Summary
| | Adult | | | | Pediatric (0-21) | | | | Unknown Age | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | Prospective | | Retrospective | | Prospective | | Retrospective | | Prospective | | Retrospective | |
| Race | n | % | n | % | n | % | n | % | n | % | n | % |
| American Indian/Alaskan Native | 2 | 0.1% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% |
| Asian | 21 | 0.8% | 4 | 1.9% | 3 | 1.9% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% |
| Black/African American | 832 | 31.2% | 57 | 27.7% | 64 | 39.8% | 4 | 13.8% | 0 | 0.0% | 0 | 0.0% |
| Native Hawaiian or Other Pacific Islander | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% |
| White | 1664 | 62.5% | 141 | 68.4% | 89 | 55.3% | 25 | 86.2% | 2 | 100.0% | 21 | 100.0% |
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| | Adult | | | | Pediatric (0-21) | | | | Unknown Age | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | Prospective | | Retrospective | | Prospective | | Retrospective | | Prospective | | Retrospective | |
| Race | n | % | n | % | n | % | n | % | n | % | n | % |
| Unknown | 6 | 0.2% | 1 | 0.5% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% |
| Other | 138 | 5.2% | 3 | 1.5% | 5 | 3.1% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% |
| Total | 2663 | 100.0% | 206 | 100.0% | 161 | 100.0% | 29 | 100.0% | 2 | 100.0% | 21 | 100.0% |
## D. Safety and Effectiveness Results
### 1. Safety Results
With regard to safety, as an *in vitro* diagnostic test, the LIAISON XL MUREX Anti-HBc test involves taking a sample of plasma or serum from a patient. The test, therefore, presents no more safety hazard to an individual being tested than other tests where blood samples are drawn.
There were no adverse effects that occurred in the PMA clinical study.
### 2. Effectiveness Results
The analysis of effectiveness was based on the 3,082 evaluable patients. Key effectiveness outcomes are presented in the tables below.
Table 11: Clinical Comparison for Prospectively Collected Samples
| HBV Classification | Positive Percent Agreement (PPA) | Negative Percent Agreement (NPA) |
| --- | --- | --- |
| Acute | 8/8 (100.0%)
95% CI: 67.6% to 100.0% | 4/4 (100.0%)
95% CI: 51.0% to 100.0% |
| Late Acute | 2/2 (100.0%)
95% CI: 34.2% to 100.0% | N/A |
| Chronic | 74/76 (97.4%)
95% CI: 90.9% to 99.3% | N/A |
| Early Recovery | 43/48 (89.6%)
95% CI: 77.8% to 95.5% | N/A |
| Recovery | 127/128 (99.2%)
95% CI: 95.7% to 99.9% | 2/3 (66.7%)
95% CI: 20.8% to 93.9% |
| Immune Due to Natural Infection | 96/104 (92.3%)
95% CI: 85.6% to 96.1% | N/A |
| HBV Vaccine Response | 1/1 (100%)
95% CI: 20.7% to 100.0% | 1113/1143 (97.4%)
95% CI: 96.3% to 98.2% |
| Not Previously Infected | N/A | 1296/1302 (99.5%)
95% CI: 99.0% to 99.8% |
| Not Interpretable | 1/1 (100%)
95% CI: 20.7% to 100.0% | 6/6 (100.0%)
95% CI: 61.0% to 100.0% |
| Total | 352/368 (95.7%)
95% CI: 93.1% to 97.3% | 2421/2458 (98.5%)
95% CI: 97.9% to 98.9% |
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Table 12: Percent Agreement for Prospectively Collected Samples
| HBV Classification | Positive Percent Agreement (PPA) | Negative Percent Agreement (NPA) |
| --- | --- | --- |
| Acute | 8/8 (100.0%)
95% CI: 67.6% to 100.0% | 4/4 (100.0%)
95% CI: 51.0% to 100.0% |
| Late Acute | 2/2 (100.0%)
95% CI: 34.2% to 100.0% | N/A |
| Chronic | 74/76 (97.4%)
95% CI: 90.9% to 99.3% | N/A |
| Early Recovery | 43/48 (89.6%)
95% CI: 77.8% to 95.5% | N/A |
| Recovery | 127/128 (99.2%)
95% CI: 95.7% to 99.9% | 2/3 (66.7%)
95% CI: 20.8% to 93.9% |
| Immune Due to Natural Infection | 96/104 (92.3%)
95% CI: 85.6% to 96.1% | N/A |
| HBV Vaccine Response | 1/1 (100%)
95% CI: 20.7% to 100.0% | 1113/1143 (97.4%)
95% CI: 96.3% to 98.2% |
| Not Previously Infected | N/A | 1296/1302 (99.5%)
95% CI: 99.0% to 99.8% |
| Not Interpretable | 1/1 (100%)
95% CI: 20.7% to 100.0% | 6/6 (100.0%)
95% CI: 61.0% to 100.0% |
| Total | 352/368 (95.7%)
95% CI: 93.1% to 97.3% | 2421/2458 (98.5%)
95% CI: 97.9% to 98.9% |
Table 13: Clinical Comparison for Retrospectively Collected Samples
| HBV Classification | Reference Anti-HBc | | | | Total |
| --- | --- | --- | --- | --- | --- |
| | + | | - | | |
| | LIAISON® XL MUREX Anti-HBc | | LIAISON® XL MUREX Anti-HBc | | |
| | + | - | + | - | |
| Acute | 92 | 0 | 2 | 3 | 97 |
| Late Acute | 32 | 0 | 0 | 0 | 32 |
| Chronic | 68 | 0 | 0 | 0 | 68 |
| Early Recovery | 9 | 0 | 0 | 0 | 9 |
| Recovery | 35 | 0 | 0 | 1 | 36 |
| Immune Due to Natural Infection | 3 | 0 | 0 | 0 | 3 |
| HBV Vaccine Response | 0 | 0 | 0 | 8 | 8 |
| Not Previously Infected | 0 | 0 | 0 | 1 | 1 |
| Not Interpretable | 1 | 0 | 0 | 1 | 2 |
| Total | 240 | 0 | 2 | 14 | 256 |
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Table 14: Percent Agreement for Retrospectively Collected Samples
| HBV Classification | Positive Percent Agreement (PPA) | Negative Percent Agreement (NPA) |
| --- | --- | --- |
| Acute | 92/92 (100.0%)
95% CI: 96.0% to 100.0% | 3/5 (60.0%)
95% CI: 23.1% to 88.2% |
| Late Acute | 32/32 (100.0%)
95% CI: 89.3% to 100.0% | N/A |
| Chronic | 68/68 (100.0%)
95% CI: 94.7% to 100.0% | N/A |
| Early Recovery | 9/9 (100.0%)
95% CI: 70.1% to 100.0% | N/A |
| Recovery | 35/35 (100.0%)
95% CI: 90.1% to 100.0% | 1/1 (100.0%)
95% CI: 20.7% to 100.0% |
| Immune Due to Natural Infection | 3/3 (100.0%)
95% CI: 43.9% to 100.0% | N/A |
| HBV Vaccine Response | N/A | 8/8 (100.0%)
95% CI: 67.6% to 100.0% |
| Not Previously Infected | N/A | 1/1 (100.0%)
95% CI: 20.7% to 100.0% |
| Not Interpretable | 1/1 (100.0%)
95% CI: 20.7% to 100.0% | 1/1 (100.0%)
95% CI: 20.7% to 100.0% |
| Total | 240/240 (100.0%)
95% CI: 98.4% to 100.0% | 14/16 (87.5%)
95% CI: 64.0% to 96.5% |
Table 15: Pediatric Cumulative (prospective and retrospective) agreement results
| HBV Classification | Positive Percent Agreement (PPA) | Negative Percent Agreement (NPA) |
| --- | --- | --- |
| Acute | 20/20 (100.0%)
95% CI: 83.9% to 100.0% | N/A |
| Late Acute | 7/7 (100.0%)
95% CI: 64.6% to 100.0% | N/A |
| Chronic | 7/7 (100.0%)
95% CI: 64.6% to 100.0% | N/A |
| Early Recovery | 1/1 (100.0%)
95% CI: 20.7% to 100.0% | N/A |
| Recovery | 5/5 (100.0%)
95% CI: 56.6% to 100.0% | N/A |
| Immune Due to Natural Infection | 3/3 (100.0%)
95% CI: 43.9% to 100.0% | N/A |
| HBV Vaccine Response | N/A | 62/63 (98.4%)
95% CI: 91.5% to 99.7% |
| Not Previously Infected | N/A | 84/84 (100.0%)
95% CI: 95.6% to 100.0% |
| Not Interpretable | N/A | 2/2 (100.0%)
95% CI: 34.2% to 100.0% |
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3. **Subgroup Analyses**
The study design enabled an assessment of assay performance by subgroup as depicted in tables above which show subjects stratified by stage of HBV infection and HBV vaccine response.
4. **Pediatric Extrapolation**
In this premarket application, existing clinical data from adult subjects was not leveraged to support approval of a pediatric patient population.
Samples from pediatric patients were tested in the clinical study in order to support a pediatric claim.
E. **Financial Disclosure**
The Financial Disclosure by Clinical Investigators regulation (21 CFR 54) requires applicants who submit a marketing application to include certain information concerning the compensation to, and financial interests and arrangement of, any clinical investigator conducting clinical studies covered by the regulation. The pivotal clinical study included 3 investigators. None of the clinical investigators had disclosable financial interests/arrangements as defined in sections 54.2(a), (b), (c), and (f). The information provided does not raise any questions about the reliability of the data
XI. **PANEL MEETING RECOMMENDATION AND FDA'S POST-PANEL ACTION**
In accordance with the provisions of section 515(c)(3) of the act as amended by the Safe Medical Devices Act of 1990, this PMA was not referred to the Microbiology Panel, an FDA advisory committee, for review and recommendation because the information in the PMA substantially duplicates information previously reviewed by this panel.
XII. **CONCLUSIONS DRAWN FROM PRECLINICAL AND CLINICAL STUDIES**
A. **Effectiveness Conclusions**
The effectiveness of the LIAISON XL MUREX Anti-HBc test for detecting antibodies to hepatitis-B core antigen in human serum and plasma (lithium and sodium heparin, sodium citrate and potassium EDTA) samples including separator tubes, on the LIAISON XL Analyzer has been demonstrated in the following patient populations: adults and pediatric patients (2 – 21 years). The results of this test may be used as an aid in the diagnosis of hepatitis B virus (HBV) infection in patients with symptoms of hepatitis or who may be at risk for hepatitis B infection. The positive agreement of the assay is 97.4% with a two-sided 95% confidence interval (CI) of 95.8% - 98.5% and the negative percent agreement is 98.4% with a two-sided 95% CI of 97.9 - 98.9%.
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B. Safety Conclusions
The risks of the device are based on nonclinical laboratory studies as well as data collected in a clinical study conducted to support PMA approval as described above. Based on the results of these studies the LIAISON XL MUREX Anti-HBc assay when used according to the manufacturer’s instructions can aid the physician in the diagnosis of HBV infection. The positive agreement of the assay is 97.4% with a two-sided 95% confidence interval (CI) of 95.8% - 98.5% and the negative percent agreement is 98.4% with a two-sided 95% CI of 97.9 - 98.9%.
C. Benefit-Risk Determination
The probable benefits of the device are also based on data collected in a clinical study conducted to support PMA approval as described above. The benefits of the assay are the determination, as part of a hepatitis B panel, the appropriate diagnosis and treatment of current or prior hepatitis B infection. Treatment for appropriate patients can mitigate the sequelae of hepatitis B infection and may result in improved morbidity and mortality in these patients. Additionally, diagnosis and appropriate treatment can potentially decrease transmission and disease burden in the general population as well as in populations at high risk for hepatitis B infection.
The probable risks of the device are also based on data collected in a clinical study conducted to support PMA approval as described above. Risks of false positive tests include improper patient management, including treatment for hepatitis B with antiviral medication. Antiviral medical has risks including toxicity and more rarely allergic reactions. Risks of false negative tests include potentially missing and undertreating a patient who has hepatitis B infection and whose clinical picture warrants antiviral treatment.
1. Patient Perspectives
This submission did not include specific information on patient perspectives for this device.
In conclusion, given the available information above, the data support the claimed intended use, the probable benefits outweigh the probable risks.
D. Overall Conclusions
The data in this application support the reasonable assurance of safety and effectiveness of this device when used in accordance with the indications for use. The probable clinical benefits outweigh the potential risks for the proposed assay considering the performance of the device in the clinical trial and the low risk and associated risk mitigations in clinical practice. The proposed assay labelling will facilitate accurate assay implementation and interpretation of results. The clinical performance observed in the prospective and retrospective clinical trial suggests
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that errors will be uncommon and that the assay may provide substantial benefits to patients as an accurate and sensitive aid in the diagnosis of hepatitis B infection.
## XIII. CDRH DECISION
CDRH issued an approval order on January 2, 2020.
The applicant’s manufacturing facilities have been inspected and found to be in compliance with the device Quality System (QS) regulation (21 CFR 820).
## XIV. APPROVAL SPECIFICATIONS
Directions for use: See device labeling.
Hazards to Health from Use of the Device: See Indications, Contraindications, Warnings, Precautions, and Adverse Events in the device labeling.
Post-approval Requirements and Restrictions: See approval order.
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