LIAISON H. pylori IgG, LIAISON H. pylori IgG Control Set

K161139 · DiaSorin, Inc. · LYR · Jul 22, 2016 · Microbiology

Device Facts

• Record ID: K161139
• Device Name: LIAISON H. pylori IgG, LIAISON H. pylori IgG Control Set
• Applicant: DiaSorin, Inc.
• Product Code: LYR · Microbiology
• Decision Date: Jul 22, 2016
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3110
• Device Class: Class 1

Indications for Use

The LIAISON® H. pylori IgG assay uses chemiluminescent immunoassay (CLIA) technology for the qualitative determination of IgG antibodies to Helicobacter pylori in human serum from symptomatic adults as an aid in the diagnosis of Helicobacter pylori infection. Assay results should be used in conjunction with other clinical or laboratory data to assist the clinician in making individual patient management decisions. The test has to be performed on the LIAISON® XL Analyzer. The LIAISON® H. pylori IgG Control Set is intended for use as assayed quality control samples to monitor the performance of the LIAISON® H. pylori IgG assay.

Device Story

LIAISON H. pylori IgG is a two-step, indirect chemiluminescent immunoassay (CLIA) for qualitative detection of IgG antibodies to H. pylori in human serum. Input: patient serum sample. Process: magnetic particles coated with H. pylori antigen bind antibodies; monoclonal anti-human IgG conjugate linked to isoluminol derivative binds; flash chemiluminescence induced by starter reagents; photomultiplier measures relative light units (RLU). Performed on LIAISON XL Analyzer. Output: qualitative index value. Used in clinical laboratories by trained personnel. Results assist clinicians in patient management decisions regarding H. pylori infection.

Clinical Evidence

Prospective study of 504 samples from symptomatic adults compared to predicate. Results: 99.2% negative percent agreement (378/381) and 95.5% positive percent agreement (105/110). Precision/reproducibility studies (12-day and 5-day) conducted per CLSI EP5-A3 and EP15-A3, showing total %CVs ranging from 3.7% to 14.2% across various sample concentrations.

Technological Characteristics

Solid-phase, two-step indirect chemiluminescent immunoassay (CLIA). Components: magnetic particles coated with H. pylori antigen, mouse monoclonal anti-human IgG conjugate linked to isoluminol derivative. Automated processing on LIAISON XL Analyzer. Measurement via photomultiplier (flash chemiluminescence). Sample volume: 10 uL. Calibration: two-point verification of stored master curve.

Indications for Use

Indicated for symptomatic adults for the qualitative determination of IgG antibodies to Helicobacter pylori in human serum as an aid in diagnosis of H. pylori infection.

Regulatory Classification

Identification

Campylobacter fetus serological reagents are devices that consist of antisera conjugated with a fluorescent dye used to identify Campylobacter fetus from clinical specimens or cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by this bacterium and provides epidemiological information on these diseases. Campylobacter fetus is a frequent cause of abortion in sheep and cattle and is sometimes responsible for endocarditis (inflammation of certain membranes of the heart) and enteritis (inflammation of the intestines) in humans.

Predicate Devices

• IMMULITE® 2000 H. pylori IgG (K000463)

Submission Summary (Full Text)

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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
ASSAY AND INSTRUMENT COMBINATION TEMPLATE

A. 510(k) Number:
K161139

B. Purpose for Submission:
To obtain substantial equivalence for the LIAISON® H. pylori IgG assay and LIAISON® H. pylori IgG Control Set.

C. Measurand:
Helicobacter pylori IgG antibodies in human serum

D. Type of Test:
Chemiluminescence Immunoassay

E. Applicant:
DiaSorin Inc.

F. Proprietary and Established Names:
LIAISON® H. pylori IgG, LIAISON® H. pylori IgG Control Set

G. Regulatory Information:
1. Regulation section:
21 CFR 866.3110 - Campylobacter fetus serological reagents
2. Classification:
Class I
3. Product codes:
LYR; Helicobacter pylori
JJX; single (specified) analyte controls (assayed and unassayed)
JJQ; colorimeter, photometer, spectrophotometer for clinical use

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4. Panel:

83 Microbiology

H. Intended Use:

1. Intended use(s):

The LIAISON® H. pylori IgG assay uses chemiluminescent immunoassay (CLIA) technology for the qualitative determination of IgG antibodies to *Helicobacter pylori* in human serum from symptomatic adults as an aid in the diagnosis of *Helicobacter pylori* infection. Assay results should be used in conjunction with other clinical or laboratory data to assist the clinician in making individual patient management decisions. The test has to be performed on the LIAISON® XL Analyzer.

The LIAISON® H. pylori IgG Control Set is intended for use as assayed quality control samples to monitor the performance of the LIAISON® H. pylori IgG assay.

2. Indication(s) for use:

Same as intended use

3. Special conditions for use statement(s):

For prescription use only

4. Special instrument requirements:

LIAISON® XL Analyzer

I. Device Description:

The LIAISON H. pylori IgG assay is a two-step, indirect assay for the determination of IgG antibodies to *Helicobacter pylori* by chemiluminescence immunoassay. The principle components of the test are magnetic particles (solid phase) coated with H. pylori antigen and anti-human IgG monoclonal antibodies labelled with an isoluminol derivative.

During the first incubation, H. pylori antibodies present in calibrators, samples or controls (sold separately) bind to the solid phase functionalized with H. pylori antigen. During the second incubation, the antibody conjugate reacts with H. pylori IgG already bound to the solid phase. After each incubation, the unbound material is removed with a wash cycle (wash buffer sold separately). Subsequently, the starter reagents (sold separately) 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 H. pylori IgG concentration present in calibrators, samples or controls.

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The calibrator concentrations (Index Values) are referenced to an in-house standard preparation. The light signal is measured by a photomultiplier as relative light units (RLU) and is proportional to the concentration of antibodies to $H$ . pylori present in the calibrator, controls or sample. Table 1 summarizes the interpretation of results.

Table 1. Interpretation of results:

| Index | Results | Interpretation |
| --- | --- | --- |
| <0.80 | Negative (No further testing) | A negative result generally indicates that the patient has not been infected, but does not always rule out acute H. pylori infection. |
| ≥0.80 and <0.90 | Equivocal (Retest) | Equivocal samples must be retested by the LIAISON® H. pylori IgG assay in order to confirm the initial result. Samples which are positive (≥0.90) at the second test should be considered positive. Samples which are negative (<0.80) at the second test should be considered negative. For samples that are equivocal on retesting; a new specimen should be collected and tested. |
| ≥0.90 | Positive (No further testing) | Indicates the presence of detectable IgG antibody to H. pylori. |

The results are only intended to be read on the LIASON® XL Analyzer (sold separately). The LIAISON XL Analyzer was FDA cleared (K103529). The LIAISON® XL Analyzer with software version 4.0.0.4 was FDA cleared in April 2013 with the DiaSorin LIAISON® TSH assay K130469. There have been changes to the LIAISON® XL Analyzer software since it was cleared under K130469, and the subject iteration of the software is 4.1.0.3 SP1 dated 10/2015.

The LIAISON® H. pylori IgG assay is an in vitro diagnostic device consisting of reagents provided in individual compartments within a plastic container called the Reagent Integral. The assay configuration for the LIAISON® H. pylori IgG assay allows for the performance of 100 tests. A list of the components that make up the Reagent Integrals is listed below in Table 2.

Table 2. Reagent Integral

| Magnetic Particles (2.4 mL) | [SORB] | Magnetic particles coated with H. pylori antigen in phosphate buffer containing BSA, surfactant, and <0.1% sodium azide. |
| --- | --- | --- |
| Calibrator 1 (1.0 mL) | [CAL|1] | Human serum containing H. pylori IgG, <0.1% sodium azide and 0.1% ProClin® 300. |
| Calibrator 2 (1.0 mL) | [CAL|2] | Human serum containing H. pylori IgG, <0.1% sodium azide and 0.1% ProClin® 300. |
| Conjugate (28.0 mL) | [CONJ] | Mouse monoclonal antibodies to human IgG conjugated to an isoluminol derivative, in phosphate buffer, BSA, 0.2% ProClin® 300 and 0.01% gentamicin sulfate. |
| Specimen Diluent (2 x 28.0 mL) | [DIL|SPE] | BSA, phosphate buffer, 0.2% ProClin® 300, an inert yellow dye. |
| Number of Tests | | 100 |

ProClin® is a trademark of the Dow Chemical Company (Dow) or an affiliated company of Dow.

All reagents are supplied ready to use.

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Materials required but not provided (system related)

| LIAISON® XL Analyzer |
| --- |
| LIAISON® Wash/System Liquid ([REF] 319100) |
| LIAISON® XL Waste Bags ([REF] X0025) |
| LIAISON® XL Cuvettes ([REF] X0016) |
| LIAISON® XL Starter Kit ([REF] 319200) |
| LIAISON® XL Disposable Tips ([REF] X0015) |

Additional required materials not provided:
LIAISON® H. pylori IgG Control Set ([REF] 318981)

J. Substantial Equivalence Information:

1. Predicate device name(s):
IMMULITE® 2000 H. pylori IgG (assay)

2. Predicate 510(k) number(s):
K000463 (assay)

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3. Comparison with predicate:

| Similarities | | |
| --- | --- | --- |
| Item | Device K161139 | Predicate K000463 |
| Intended Use | The LIAISON® H. pylori IgG assay uses chemiluminescent immunoassay (CLIA) technology for the qualitative determination of IgG antibodies to Helicobacter pylori in human serum from symptomatic adults as an aid in the diagnosis of Helicobacter pylori infection. Assay results should be used in conjunction with other clinical or laboratory data to assist the clinician in making individual patient management decisions. The test has to be performed on the LIAISON® XL Analyzer.The LIAISON® H. pylori IgG Control Set is intended for use as assayed quality control samples to monitor the performance of the LIAISON® H. pylori IgG assay. | For in vitro diagnostic use with the IMMULITE® 2000 Systems Analyzers – for the qualitative detection of IgG antibodies to Helicobacter pylori in human serum from symptomatic adults, as an aid in the diagnosis of Helicobacter pylori infection |
| Measured Analyte | IgG antibodies to H. pylori | Same |
| Assay Type | Solid Phase Two Step Chemiluminescent | Same |
| Sample Handling | Automated | Same |
| Reagent Storage | On-board or in refrigerator @ 2-8°C | In refrigerator @ 2-8°C |
| Calibration | Two point verification of stored master curve | Same |
| Calibration Calculation of Result | Qualitative assay | Same |
| Sample Matrix | Human Serum | Same |
| Sample SizeVolume | 10 μL | Same |
| Controls | Provided separately | Same |

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| Differences | | |
| --- | --- | --- |
| Item | Device K161139 | Predicate K000463 |
| Unit of Measure | Index | U/mL |
| Assay Time | 30 minutes | 60 minutes |
| Conjugate | Mouse monoclonal antibodies to human IgG linked to an isoluminol derivative | Monoclonal murine anti-human IgG antibodies labeled with alkaline phosphatase in buffer |
| Measurement System | Photomultiplier (flash chemiluminescence reader) | Luminometer |
| Cutoff | 0.85 Index | 1.00 U/mL |
| Equivocal Zone | 0.80 – < 0.90 Index | 0.90 – < 1.10 U/mL |
| Controls | 2 levels: negative and positive | 3 levels: negative, low positive, positive |
| Control Stability Open Use | 12 weeks | 2 weeks |
| Calibration Stability | 4 weeks | 1 week |

# K. Standard/Guidance Document Referenced (if applicable):

- EP05-A2, Evaluation of Precision Performance of Quality Measurement Methods; Approved Guideline - Second Edition 2004
- Clinical and Laboratory Standards Institute (CLSI) EP15-A3, Vol .28, No.3, User Verification of Precision and Estimation of Bias; Approved Guideline - Third Edition
- EP07-A2, Interference Testing in Clinical Chemistry - Approved Guideline - Second Edition 2005

# L. Test Principle:

This test is a Chemiluminescence Immunoassay (CLIA) – Immunoassay technology based on the emission of light as a result of a chemical reaction. During the first incubation, Helicobacter pylori antibodies present in diluted calibrators, samples or controls bind to the solid phase. During the second incubation, the monoclonal antibody conjugate reacts with anti- $H$ . pylori IgG that is already bound to the solid phase. After each of the incubations, 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 therefore, the amount of isoluminol-antibody conjugate, are measured by a photomultiplier as RLUs and are indicative of the presence of anti- $H$ . pylori IgG in calibrators, samples or controls.

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# M. Performance Characteristics (if/when applicable):

# 1. Analytical performance:

# a. Precision/Reproducibility:

Precision was assessed by measuring repeatability at one site using two kit controls and six serum samples containing high negative (samples #1 and #2), low positive (samples #3 and #4) and moderate positive (samples #5 and #6) concentrations of $H$ pylori IgG. Samples and kit controls (negative and positive) were assayed in duplicate in two runs per day over 12 operating days with multiple technicians. Mean, standard deviation, and coefficient of variation (%CV) were calculated using multiple sources of variability that included within-run, within-day, between-day, and total variability. The results are summarized in Table 3

Table 3. Precision Study Results

| Sample ID | Mean Index | Within Run | | Within Day | | Between Day | | Total | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Neg Ctrl | 1341* | 115 | 8.6% | 46.8 | 3.5% | 145 | 10.8% | 190 | 14.2% |
| Neg Ctrl | 1320* | 120 | 9.1% | 52.6 | 4.0% | 119 | 9.0% | 177 | 13.4% |
| Pos Ctrl | 2.77 | 0.145 | 5.2% | 0.119 | 4.3% | 0.112 | 4.1% | 0.218 | 7.9% |
| Pos Ctrl | 2.73 | 0.144 | 5.3% | 0.176 | 6.5% | 0.053 | 1.9% | 0.234 | 8.6% |
| Sample #1 | 0.74 | 0.049 | 6.6% | 0.043 | 5.7% | 0.051 | 6.8% | 0.082 | 11.1% |
| Sample #2 | 0.71 | 0.048 | 6.7% | 0.000 | 0.0% | 0.030 | 4.2% | 0.055 | 7.7% |
| Sample #3 | 1.32 | 0.071 | 5.4% | 0.040 | 3.1% | 0.075 | 5.7% | 0.111 | 8.4% |
| Sample #4 | 1.25 | 0.081 | 6.5% | 0.015 | 1.2% | 0.053 | 4.3% | 0.098 | 7.9% |
| Sample #5 | 1.52 | 0.076 | 5.0% | 0.074 | 4.9% | 0.000 | 0.0% | 0.106 | 7.0% |
| Sample #6 | 1.50 | 0.084 | 5.6% | 0.042 | 2.8% | 0.095 | 6.3% | 0.133 | 8.9% |

Sample N=48
*Precision calculations for the two negative controls were based on the RLU signal instead of the Index value

Reproducibility was assessed across three testing sites using two kit controls and six serum samples containing high negative, low positive and moderate positive concentrations of $H$ pylori IgG and kit controls (negative and positive) as duplicate samples were assayed in replicates of three. Mean, standard deviation, and coefficient of variation (%CV) were calculated using multiple sources of variability that include within-run, within-day, between-day, site to site and total variability. Table 4 illustrates the following results that were obtained from three sites with two kit lots assayed in duplicate in two assays per day over 12 operating days.

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Table 4. Reproducibility Study Results

| Sample ID | Mean Index | Within Run | | Run to Run Within Day | | Day to Day Within Site | | Site to Site | | Total | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Neg Ctrl | 1013* | 54.0 | 5.3% | 25.4 | 2.5% | 19.1 | 1.9% | 50.4 | 5.0% | 80.4 | 7.9% |
| Neg Ctrl | 996* | 43.7 | 4.4% | 25.4 | 2.6% | 0.900 | 0.1% | 79.8 | 8.0% | 94.5 | 9.5% |
| Pos Ctrl | 3.34 | 0.111 | 3.3% | 0.060 | 1.8% | 0.013 | 0.4% | 0.062 | 1.9% | 0.141 | 4.2% |
| Pos Ctrl | 3.36 | 0.103 | 3.1% | 0.012 | 0.4% | 0.068 | 2.0% | 0.019 | 0.6% | 0.126 | 3.7% |
| Sample #1 | 0.626 | 0.035 | 5.6% | 0.010 | 1.6% | 0.016 | 2.5% | 0.061 | 9.8% | 0.073 | 11.7% |
| Sample #2 | 0.628 | 0.025 | 4.0% | 0.018 | 2.9% | 0.005 | 0.7% | 0.047 | 7.4% | 0.056 | 9.0% |
| Sample #3 | 1.28 | 0.043 | 3.4% | 0.004 | 0.3% | 0.030 | 2.4% | 0.064 | 5.0% | 0.083 | 6.5% |
| Sample #4 | 1.27 | 0.050 | 3.9% | 0.011 | 0.9% | 0.035 | 2.7% | 0.044 | 3.5% | 0.076 | 6.0% |
| Sample #5 | 1.82 | 0.061 | 3.3% | 0.049 | 2.7% | 0.045 | 2.5% | 0.067 | 3.7% | 0.113 | 6.2% |
| Sample #6 | 1.74 | 0.060 | 3.4% | 0.034 | 1.9% | 0.041 | 2.4% | 0.067 | 3.8% | 0.104 | 6.0% |

Sample N=90
* Precision calculations for the two negative controls were based on the RLU signal instead of the Index value

b. Linearity/assay reportable range:

Not applicable

c. Traceability, Stability, Expected values (controls, calibrators, or methods):

Traceability

The calibrator concentrations (Index Values) are referenced to an in-house standard preparation.

Stability

Reagents Integral:

Open use stability at $2 - 8^{\circ}\mathrm{C}$ was performed using one Reagent Integral Lot at specified intervals. All testing results were acceptable for up to eight weeks. An open use stability of eight weeks at $2 - 8^{\circ}\mathrm{C}$ was supported. Open use stability on board the LIAISON Analyzer was performed using one Reagent Integral Lot at specified intervals. All testing results were acceptable for up to eight weeks (see Table 5a). Controls were tested at $2 - 8^{\circ}\mathrm{C}$ and found to be stable up to the stated expiration date if unopened or up to 12 weeks after opening (see Table 5b). Serum sample stability was acceptable for up to three days at $2 - 8^{\circ}\mathrm{C}$ or for up to five freeze thaw cycles (see Table 5c).

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Table 5a. Reagent stability

| Unopened stored @ 2-8°C | Up to the stated expiration date |
| --- | --- |
| Opened stored @ 2-8°C | 8 weeks |
| Opened stored on analyzer | 8 weeks |

Table 5b. Control stability

| Unopened stored @ 2-8°C | Up to the stated expiration date |
| --- | --- |
| Opened stored @ 2-8°C | 12 weeks |

Table 5c. Sample stability

| Storage @ 2-8°C | 3 days |
| --- | --- |
| Freeze/Thaw | Up to 5 freeze/thaw cycles |

# Expected values:

- Calibrator 1 is manufactured to have a target Index value range of $0.80 - 2.2$ .
- Calibrator 2 is manufactured to have a target Index value range of $4.0 - 8.0$ .
- The negative control is manufactured to a target Index value less than $0.6^{*}$ .
- The positive control is manufactured to have a target Index value of $1.75^{*}$ .

*The target Index value range for 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.

# d. Detection limit:

Not applicable

# e. Analytical specificity:

# Cross reactivity:

Controlled studies of potentially cross-reacting microorganisms that may cause symptoms similar to an $H.$ pylori infection were performed on the LIAISON® $H.$ pylori IgG assay. None of the organisms affected positive or negative test results. Table 6 is a list of all the organisms tested.

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Table 6. Cross reactivity organisms

| Organism | Organism | Organism |
| --- | --- | --- |
| Aeromonas hydrophila | Enterococcus faecalis | Salmonella Group B |
| Bacillus cereus | Escherichia coli | Salmonella Group C |
| Bacillus subtilis | Escherichia fergusonii | Salmonella Group D |
| Campylobacter coli | Escherichia hermannii | Salmonella Group E |
| Campylobacter fetus | Haemophilus influenzae | Serratia liquefaciens |
| Campylobacter hyointestinalis | Helicobacter pylori | Shigella boydii |
| Campylobacter jejuni | Klebsiella pneumoniae | Shigella flexneri |
| Campylobacter upsaliensis | Lactobacillus lactis | Shigella sonnei |
| Candida albicans | Listeria monocytogenes | Staphylococcus aureus |
| Citrobacter freundii | Peptostreptococcus anaerobius | Staphylococcus epidermidis |
| Clostridium difficile | Plesiomonas shigelloides | Vibrio parahaemolyticus |
| Clostridium perfringens | Proteus vulgaris | Yersinia enterocolitica |
| Clostridium sordellii | Pseudomonas aeruginosa | |
| Enterobacter cloacae | Pseudomonas fluorescens | |

# High Dose Hook Effect (false negative):

Analysis of high-dose hook effect was evaluated by testing three samples with $H.$ pylori IgG levels out-of-range $&gt; 9.4$ index values. The testing produced index values that were above the measuring range with no sample misclassification, indicating that no hook effect was observed.

# Interference:

Testing was performed to determine interference in the presence of exogenous substances from commonly used medications (Table 7a) relevant to gastrointestinal tract complications or endogenous substances that may be found in serum (Table 7b). Two matched sample pools containing antibodies to $H.$ pylori IgG near the clinical decision point (low positive and high negative) were tested neat and spiked with the respective interferent.

Acceptance criteria required that the percent change in signal not be more than $+/- 10\%$ and that the qualitative result must not change. No interference was observed in the LIAISON® H. pylori IgG at the highest concentration for each substance listed below.

Table 7a Exogenous substances

| Substance (Drug) | Tested Concentration |
| --- | --- |
| Barium Sulfate | 5.0 mg/mL |
| Stearic Acid | 2.65 mg/mL |
| Palmitic Acid | 1.3 mg/mL |
| Imodium® AD | 0.007 mg/mL |
| Kaopectate | 0.87 mg/mL |
| Metronidazole | 12.5 mg/mL |
| Mucin | 3.33 mg/mL |

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| Substance (Drug) | Tested Concentration |
| --- | --- |
| Mylanta | 4.2 mg/mL |
| Pepto Bismol® | 0.87 mg/mL |
| MiraLAX®/PEG 3350 | 25 mg/mL |
| Prilosec | 0.5 mg/mL |
| Gas X®/Simethicone | 0.625 mg/mL |
| Tagamet | 0.5 mg/mL |
| Tums® | 0.5 mg/mL |
| Vancomycin | 2.5 mg/mL |

Table 7b. Endogenous substances

| Substance (Endogenous) | Tested Concentration |
| --- | --- |
| Triglycerides | 3000 mg/dL |
| Hemoglobin | 500 mg/dL |
| Unconjugated bilirubin | 40 mg/dL |
| Conjugated bilirubin | 40 mg/dL |
| Ascorbic Acid | 6000 mg/dL |
| Cholesterol | 500 mg/dL |
| Protein | 13500 mg/dL |
| Whole Blood | 25% |
| White Blood Cells | 5% |

f. Assay cut-off:

The LIAISON® H. pylori IgG assay defines a sample as positive if the Index value is greater than or equal to 0.90 Index, and defined as negative if the Index value is less than 0.80 Index. Samples with results greater than or equal to 0.80 Index and less than 0.90 Index are classified as equivocal.

The preliminary cutoff was determined by testing 417 selected $H.$ pylori positive and negative serum samples in parallel with the LIAISON® $H.$ pylori IgG assay and a comparison method. This cut-off was validated during clinical studies by testing a prospective population of 504 specimens; that were 110 positive for IgG antibodies to Helicobacter pylori, 381 negative for IgG antibodies to Helicobacter pylori, and 13 equivocal results as determined by the IMMULITE® 2000 H. pylori IgG assay. The 13 equivocal results by the comparison method were not included in the cutoff validation data analysis. The results of the cutoff assay were determined to be appropriate for the LIAISON® $H.$ pylori IgG assay.

2. Comparison studies:

a. Method comparison with predicate device:

Not applicable

b. Matrix comparison:

Not applicable

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# 3. Clinical studies:

a. Clinical Sensitivity:

Not applicable

b. Clinical specificity:

Not applicable

c. Other clinical supportive data (when a. and b. are not applicable):

# Comparative testing:

A prospective study was performed to compare the performance of the LIAISON® $H$ pylori IgG assay to an FDA-cleared predicate device. The study consisted of 504 samples from individuals who were sent to the laboratory for Helicobacter pylori IgG testing. The age of the patients ranged from 18-91 years old.

The positive percent agreement and negative percent agreement and the $95\%$ confidence interval for each prospective population are shown in Table 8 below: Equivocals from the comparator assay were removed from the analysis. Equivocals from the subject assay were calculated against the performance calculations for Positive Percent Agreement and Negative Percent Agreement.

Table 8. Performance of the LIAISON H. pylori IgG Assay

| LIAISON® H. pylori IgG | Comparator Assay | | | Total |
| --- | --- | --- | --- | --- |
| | Positive | Equivocal | Negative | |
| Positive | 105 | 7 | 1 | 113 |
| Equivocal | 1 | 2 | 2 | 5 |
| Negative | 4 | 4 | 378 | 386 |
| Total | 110 | 13 | 381 | 504 |
| | Percent Agreement | Exact 95% Confidence Intervals | | |
| Positive | 95.5% (105/110) | 90.4 – 98.4% | | |
| Negative | 99.2% (378/381) | 97.9 – 99.8% | | |

# 4. Clinical cut-off:

Not applicable

# 5. Expected values/Reference range:

The observed seroprevalence from the LIAISON® $H.$ pylori IgG assay was calculated from the 504 samples sent to the lab for $H.$ pylori IgG testing. The samples were collected from multiple U.S. geographical locations from 151 male (30%) and 353 female (70%) adult subjects. Known ages ranged from 18 to 91 years.

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The *H. pylori* seroprevalence may vary depending upon geographical location, age, gender, type of test employed, specimen collection and handling procedures as well as clinical history of the patient.

The *H. pylori* IgG seroprevalence as observed with the LIAISON® *H. pylori* IgG assay is 22.4% (113/504) for the current submission. Equivocal results from the LIAISON® *H. pylori* IgG assay are considered negative for the seroprevalence calculations.

## N. Instrument Name:

LIAISON® XL Analyzer

## O. System Descriptions:

1. **Modes of Operation:**

The LIAISON® *H. pylori* IgG assay is a two-step, indirect chemiluminescence immunoassay (CLIA) for qualitative determination of IgG antibodies to *H. pylori*. The principal components of the test are magnetic particles (solid phase) coated with *H. pylori* antigen and a conjugate of anti-human IgG monoclonal antibodies labelled with an isoluminol derivative. During the first incubation, *H. pylori* antibodies present in calibrators, samples or controls bind to the solid phase. During the second incubation, the monoclonal antibody conjugate reacts with *H. pylori* IgG that is already bound to the solid phase. After each incubation, 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 therefore, the amount of isoluminol-antibody conjugate, are measured by a photomultiplier as relative light units (RLU) and are indicative of the presence of *H. pylori* IgG in calibrators, samples or controls.

Does the applicant’s device contain the ability to transmit data to a computer, webserver, or mobile device?

☐ Yes ☐ No

Does the applicant’s device transmit data to a computer, webserver, or mobile device using wireless transmission?

☐ Yes ☐ No

2. **Software:**

FDA has reviewed applicant’s Hazard Analysis and software development processes for this line of product types:

☑ Yes ☐ No

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3. Specimen Identification:

Specimens are identified by unique barcodes

4. Specimen Sampling and Handling:

Specimens can be processed directly from primary collection vials or as aliquots of the specimen in secondary vials.

5. Calibration:

DiaSorin's LIAISON® H. pylori IgG assay generates a continuous response (relative light units, RLU) which is used in sample grading to provide a qualitative (positive, negative, or equivocal) reportable result. The sample grading is based on the use of a calibration curve referenced to an 'In-house' anti-H. pylori IgG reference standard curve (Master Curve) and is controlled by the use of two calibrators (Calibrator 1 and Calibrator 2) provided in the Reagent Integral.

The Master Curve is stored on the LIAISON® XL Analyzer and specifically matched to the kit in use via the instructions encoded in the RFID tag attached to the Reagent Integral. Each 10 point Master Curve has been generated by a mathematical elaboration of the data resulting from multiple testing (a minimum of 10 runs) of Master Standards.

The Master Standards are prepared from pooled human serum positive for anti-H. pylori IgG also referred to as the 'in house' Primary Standard Reference Preparation.

The kit calibrators are manufactured by diluting stock solutions consisting of individual or pooled human serum positive for anti-H. pylori IgG at an established Index value with Universal Negative Serum according to MP25832 and MP25833. The kit calibrators are tested with a specific Integral lot against the Master Calibrators to assess the concentration. They are subsequently corrected by dilution or concentration if the result (Index value) is out of the target range.

Calibrator 1 is manufactured to have a target anti-H. pylori IgG of 1.2 Index value. Calibrator 2 is manufactured to have a target anti-H. pylori IgG of 6.0 Index value.

The Calibrators are assayed by the user with a specific Reagent Integral lot to transform the Master Curve into a Working Curve and further used to calculate sample results. The LIAISON® XL Analyzer Working Curve is obtained by the user during assay calibration by assigning a curve to the two point kit calibrators based upon the Master Curve. This Working Curve is used to calculate the patient sample results. The Analyzer is calibrated in triplicate whenever one of the following conditions occurs:

- Quality Control results are out of the acceptable range.
- With each new lot of reagents (Reagent Integral or Starter Reagents)
- After each servicing of the LIAISON® XL Analyzer
- The previous calibration was performed more than four weeks before

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6. Quality Control:

LIAISON® H. pylori IgG Control Set ([REF] 318981) is intended to monitor for substantial reagent failure. LIAISON® controls should be run in singlicate to monitor the assay performance. Quality control is required to be performed once per day of use, or according to the guidelines or requirements of local regulations or accredited organizations. It is recommended that the user refer to CLSI C24-A35 and 42 CFR 493.1256(c) for guidance on appropriate quality control practices.

The expected range of control concentrations is provided on the certificate of analysis, the test is valid. If control values lie outside the expected ranges, the test is invalid and patient results cannot be reported. Assay calibration should be performed if a control failure is observed and controls and patient specimens must be repeated.

P. Other Supportive Instrument Performance Characteristics Data Not Covered In The "Performance Characteristics" Section above: Not applicable

Q. Proposed Labeling:

The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

R. Conclusion:

The submitted information in this premarket notification is complete and supports a substantial equivalence decision.