Elecsys Syphilis

K160910 · Roche Diagnostics · LIP · Jul 28, 2016 · Microbiology

Device Facts

• Record ID: K160910
• Device Name: Elecsys Syphilis
• Applicant: Roche Diagnostics
• Product Code: LIP · Microbiology
• Decision Date: Jul 28, 2016
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3830
• Device Class: Class 2

Intended Use

Immunoassay for the in vitro qualitative determination of total antibodies (IgG and IgM) to Treponema pallidum in human serum and plasma. The test is intended as an aid in the diagnosis of syphilis infection in conjunction with clinical signs and symptoms. The Elecsys Syphilis immunoassay is not intended for use in screening blood or tissue donors. The effectiveness of this assay in testing blood or tissue donors has not been established. The electrochemiluminescence immunoassay "ECLIA" is intended for use on the cobas e 411 analyzer. PreciControl Syphilis is intended for the quality control of the Elecsys Syphilis immunoassay on the cobas e 411 analyzer.

Device Story

Fully automated, qualitative electrochemiluminescence immunoassay (ECLIA) for detection of total anti-T. pallidum antibodies (IgG/IgM) in human serum/plasma. Uses double antigen sandwich format: recombinant T. pallidum antigens labeled with biotin or ruthenium complex bind to patient antibodies; complex binds to streptavidin-coated microparticles immobilized magnetically on electrode. Voltage application induces chemiluminescent emission measured by photomultiplier. Performed on cobas e 411 analyzer by laboratory personnel. Output is cutoff index (COI) value; COI ≥ 1.0 is reactive, < 1.0 is non-reactive. Results aid clinical diagnosis of syphilis when interpreted with clinical signs, symptoms, and other serologic tests. Benefits include automated, high-throughput screening for syphilis infection.

Clinical Evidence

Clinical study of 2,660 specimens (2,282 prospective, 169 retrospective, 209 healthy). Performance evaluated against a composite comparator (treponemal chemiluminescent immunoassay, RPR, and TP-PA). Prospective cohort: 100% PPA (228/228; 95% CI: 98.4-100.0%) and 99.2% NPA (2038/2054; 95% CI: 98.7-99.6%). Retrospective cohort: 98.7% PPA (155/157; 95% CI: 95.5-99.9%) and 100% NPA (12/12). No invalid results reported.

Technological Characteristics

Double antigen sandwich electrochemiluminescence immunoassay (ECLIA). Uses biotinylated and ruthenium-labeled recombinant T. pallidum antigens (TpN15, TpN17, TpN47). Solid phase: streptavidin-coated microparticles. Detection: chemiluminescence via photomultiplier. Instrument: cobas e 411 analyzer. Sample types: serum, K2/K3 EDTA, Li-Heparin, Na Citrate, CPDA plasma. Qualitative output based on 1.0 COI cut-off.

Indications for Use

Indicated for the qualitative detection of total antibodies (IgG and IgM) to Treponema pallidum in human serum and plasma as an aid in the diagnosis of syphilis infection. Not for use in screening blood or tissue donors.

Regulatory Classification

Identification

Treponema pallidum treponemal test reagents are devices that consist of the antigens, antisera and all control reagents (standardized reagents with which test results are compared) which are derived from treponemal sources and that are used in the fluorescent treponemal antibody absorption test (FTA-ABS), the Treponema pallidum immobilization test (T.P.I.), and other treponemal tests used to identify antibodies to Treponema pallidum directly from infecting treponemal organisms in serum. The identification aids in the diagnosis of syphilis caused by bacteria belonging to the genus Treponema and provides epidemiological information on syphilis.

Predicate Devices

• Immulite 2000 Syphilis Screen test system (K091361)

Submission Summary (Full Text)

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Image /page/0/Picture/1 description: The image is a black and white logo for the Department of Health & Human Services - USA. The logo features a stylized image of three human profiles facing right, with flowing lines representing hair or clothing. The profiles are arranged in a row, with the first profile being the most prominent and the other two slightly behind it. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is arranged in a circular fashion around the image.

Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

Roche Diagnostics Angelo Pereira Regulatory Affairs Senior Program Manager 9115 Hague Road Indianapolis, IN, 46250

Re:K160910

Trade/Device Name: Elecsys Syphilis and PreciControl Syphilis Regulation Number: 21 CFR 866.3830 Regulation Name: Treponema pallidum treponemal test reagents Regulatory Class: Class II Product Code: LIP, JJX Dated: July 22, 2016 Received: July 25, 2016

Dear Mr. Pereira:

This letter corrects our substantially equivalent letter of July 28, 2016.

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug. and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21

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CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

If you desire specific advice for your device on our labeling regulation (21 CFR Part Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number [phone] or [phone] or at its Internet address http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number [phone] or [phone] or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely.

for Uwe Scherf, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health

Enclosure

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## Indications for Use

510(k) Number (if known) K160910

Device Name Elecsys Syphilis PreciControl Syphilis

#### Indications for Use (Describe)

Immunoassay for the in vitro qualitative detection of total antibodies (IgG and IgM) to Treponema pallidum in human serum and plasma. The test is intended as an aid in the diagnosis of syphilis infection with clinical signs and symptoms.

The Elecsys Syphilis immunoassay is not intended for use in screening blood or tissue donors. The effectiveness of this assay in testing blood or tissue donors has not been established.

The electrochemiluminescence immunoassay "ECLIA" is intended for use on the cobas e 411 analyzer.

PreciControl Syphilis is intended for the quality control of the Elecsys Syphilis immunoassay on the cobas e 411 analyzer.

X Prescription Use (Part 21 CFR 801 Subpart D)

Over-The-Counter Use (21 CFR 801 Subpart C)

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# Elecsys Syphilis

# 510(k) Summary

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of 21 CFR 807.92.

| Submitter Name | Roche Diagnostics |
|----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Address | 9115 Hague Road<br>P.O. Box 50416<br>Indianapolis, IN 46250-0416 |
| Contact | Angelo Pereira<br>Phone: [phone]<br>FAX: [phone]<br>Email: [e-mail] |
| Date Prepared | July 21, 2016 |
| Proprietary Name | Elecsys Syphilis |
| Common Name | Syphilis assay |
| Classification Name | Treponema pallidum treponemal test reagent |
| Product Codes | Product Code: LIP; 21CFR866.3830<br>Control Product Code: JJX |
| Predicate Devices | Immulite 2000 Syphilis Screen test system, K091361 |
| Establishment Registration | For Elecsys Syphilis, the establishment registration number for Roche<br>Diagnostics GmbH in Mannheim, Germany is 9610126, and for Penzberg,<br>Germany, 9610529. The establishment registration number for Roche<br>Diagnostics in the United States is 1823260. |

#### DEVICE DESCRIPTION 1.

The Elecsys Syphilis assay is a fully automated qualitative assay detecting IgG and IgM antibodies to Treponema pallidum, the causative agent of syphilis. Assay results, in conjunction

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with other laboratory results and clinical information, may be used to provide presumptive evidence of active or previous infection with Treponema pallidum in persons with signs and symptoms of syphilis, as well as in patients at risk for syphilis infection. This assay does not determine the stage of infection or associated disease.

PreciControl Syphilis is a lyophilized control based on human serum. It is used for monitoring the accuracy of the Elecsys Syphilis immunoassay.

#### 2. INTENDED USE

#### Elecsys Syphilis:

Immunoassay for the in vitro qualitative determination of total antibodies (IgG and IgM) to Treponema pallidum in human serum and plasma. The test is intended as an aid in the diagnosis of syphilis infection in conjunction with clinical signs and symptoms.

The Elecsys Syphilis immunoassay is not intended for use in screening blood or tissue donors. The effectiveness of this assay in testing of blood and tissue donors has not been established.

The electrochemiluminescence immunoassay "ECLIA" is intended for use on the cobas e 411 analyzer.

#### PreciControl Syphilis:

PreciControl Syphilis is intended for the quality control of the Elecsys Syphilis immunoassay on cobas e 411 analyzer.

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#### TECHNOLOGICAL CHARACTERISTICS 3.

The Elecsys Syphilis assay is a qualitative assay that uses the established double antigen sandwich format. Biotinylated T. pallidum-specific recombinant antigens (TpN15, TpN17 and TpN47) and T. pallidum-specific recombinant antigens (TpN15, TpN17 and TpN47) labeled with a ruthenium complex react with anti T. pallidum-specific antibodies to form a sandwich complex. The assay uses monomeric and polymeric antigens, ensuring the detection of both IgG and IgM anti-treponemal antibodies. After addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically bound onto the surface of the electrode. Unbound substances are then removed with ProCell. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier.

The predicate device is a solid phase, one-step chemiluminescent enzyme immunoassay. The solid phase (bead) is coated with purified recombinant T. pallidum 17 (Tp17) antigen. The liguid phase consists of alkaline phosphatase (bovine calf intestine) conjugated to purified recombinant T. pallidum 17 (Tp17) antigen.

Patient sample and the reagent are incubated together with the coated bead. During this time, total antibody to T. pallidum in the sample forms the antigen sandwich complex with purified recombinant T. pallidum 17 (Tp17) antigen on the bead and enzyme conjugated purified recombinant T. pallidum 17 (Tp17) antigen in the reagent. Unbound patient sample and enzyme conjugate are then removed by centrifugal washes. Finally, chemiluminescent substrate is added to the reaction tube containing the bead and the signal is generated in proportion to the bound enzyme.

Both the predicate device and Elecsys Syphilis provide prepackaged reagents, calibrators and controls for use on automated test systems. A comparison of the important similarities and differences of these assays is provided in the following table:

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### Table of similarities and differences

| Parameter | New Device | Predicate |
|-------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Intended Use | Immunoassay for the in vitro<br>qualitative determination of total<br>antibodies (IgG and IgM) to<br>Treponema pallidum in human serum<br>and plasma. The test is intended as an<br>aid in the diagnosis of syphilis infection<br>in conjunction with clinical signs and<br>symptoms.<br>The Elecsys Syphilis assay is not<br>intended for use in screening blood or<br>plasma donors.<br>The electrochemiluminescence<br>immunoassay "ECLIA" is intended for<br>use on cobas e 411 analyzer | The IMMULITE 2000 Syphilis Screen<br>test is a treponemal testing procedure<br>for the qualitative detection of<br>antibodies to Treponema pallidum in<br>human serum or heparinized plasma<br>on the IMMULITE 2000 analyzer as<br>an aid I the diagnosis of syphilis.<br>The IMMULITE 2000 Syphilis Screen<br>test is not intended for use in<br>screening blood or plasma donors. |
| Analytes measured | Antibodies to Treponema pallidum | same |
| Instrument | Cobas e 411 | IMMULITE 2000 Systems |
| Measurement | Qualitative | same |
| Antigens used | Recombinant antigens TpN17,<br>TpN15 andTpN47 | Recombinant antigen Tp17 |
| Cut-off | <1.00 Non-reactive<br>≥1.00 Reactive | <0.9 Non-reactive<br>≥0.9 to <1.1 Indeterminate<br>≥1.1 Reactive |
| Sample type | Serum, K2 EDTA, K3 EDTA, CPDA,<br>NaCitrate and Li Heparin | Serum, heparinized plasma |
| Assay type | Double antigen sandwich<br>electrochemiluminescence<br>immunoassay | Enzyme labeled, one-step<br>chemiluminescent immunoassay |

#### 4. NON-CLINICAL PERFORMANCE EVALUATION

### Precision

Precision was evaluated with serum samples on a single cobas e 411 Immunoassay Analyzer according to CLSI guideline EP5-A2. One reagent lot was evaluated. The protocol was performed by testing 2 controls (PreciControl 1 and PreciControl 2) and 6 human sera (HS) (negative, near cut-off, positive) in duplicate per run, 2 runs per day for 21 days. The samples were run in randomized order on the analyzer.

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| | | Repeatability | | | Intermediate precision | |
|----------------|------------|---------------|----------------------|-------------|------------------------|----|
| Sample | Mean [COI] | SD<br>[COl] | CV [%]<br>(UCL* 95%) | SD<br>[COI] | CV [%]<br>(UCL* 95%) | n |
| HS negative 1 | 0.103 | 0.002 | 1.6 (2.0) | 0.003 | 3.2 (4.1) | 84 |
| HS negative 2 | 0.821 | 0.0174 | 2.1 (2.7) | 0.019 | 2.3 (2.7) | 84 |
| HS positive 1 | 1.01 | 0.028 | 2.8 (3.5) | 0.033 | 3.2 (3.9) | 84 |
| HS positive 2 | 1.12 | 0.018 | 1.6 (2.1) | 0.022 | 1.9 (2.3) | 84 |
| HS positive 3 | 9.99 | 0.171 | 1.7 (2.2) | 0.262 | 2.6 (3.2) | 84 |
| HS positive 4 | 50.2 | 0.986 | 2.0 (2.5) | 1.24 | 2.5 (3.0) | 84 |
| PreciControl 1 | 0.106 | 0.003 | 2.4 (3.1) | 0.004 | 4.1 (5.1) | 84 |
| PreciControl 2 | 4.95 | 0.101 | 2.1 (2.6) | 0.161 | 3.2 (4.1) | 84 |

### Endogenous Interferences

Interference by endogenous substances was evaluated at three anti-T. pallidum antibody concentrations (negative, near cut-off and positive). Each serum pool was spiked with the interferent to the levels indicated in the table below.

| | Interfering substance<br>measured up to | No interference seen up<br>to | Label Claim |
|-----------------------|-----------------------------------------|-------------------------------|-------------|
| Intralipid® (Lipemia) | 2000 mg/dL | 2000 mg/dL | 2000 mg/dL |
| Biotin | 70 ng/mL | 70 ng/mL | 60 ng/mL |
| Bilirubin | 66 mg/dL | 66 mg/dL | 66 mg/dL |
| Hemoglobin | 1000 mg/dL | 1000 mg/dL | 500 mg/dL |
| Rheumatoid Factor | 1500 IU/mL | 1500 IU/mL | 1500 IU/mL |
| human serum albumin | 10 g/dL | 10 g/dL | 10 g/dL |
| human IgG | 7.0 g/dL | 6.3 g/dL | 32 g/L |
| human IgM | 1.0 g/dL | 1.0 g/dL | 10 g/L |
| human IgA | 7.0 g/dL | 2.8 g/dL | 2.8 g/dL |

#### Drug interferences

16 pharmaceutical compounds were spiked into human serum samples at three anti-T. pallidum antibody concentrations (negative, low-positive, high positive) and tested with the Elecsys Syphilis assay on the cobas e 411 analyzer. The concentration of the spiked aliquots was determined in 3-fold determination and compared to the anti-T. pallidum antibody concentration

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determined for the reference aliquot (also in 3-fold determination) on one cobas e 411 analyzer. No interference was observed at the levels shown in the table below.

| Drug tested | Conc. of spiked drug tested (mg/L) |
|----------------------|------------------------------------|
| Acetylcystein | 150 |
| Ampicillin-Na | 1000 |
| Ascorbic acid | 300 |
| Cyclosporine | 5 |
| Cefoxitin | 2500 |
| Heparin | 5000 U/L |
| Levodopa | 20 |
| Methyldopa +1.5 | 20 |
| Metronidazole | 200 |
| Phenylbutazone | 400 |
| Doxycyclin | 50 |
| Acetylsalicylic Acid | 1000 |
| Rifampicin | 60 |
| Acetaminophen | 200 |
| Ibuprofen | 500 |
| Theophylline | 100 |

### Serum Plasma Matrix comparison

The effect of anticoagulants on the Elecsys Syphilis Immunoassay was determined by comparing values obtained from native samples spiked with anti-T. pallidum antibody (single donors) drawn into serum and plasma tubes.

The data support the package insert claim that serum, serum separation tubes, Li-Heparin plasma tubes, K2-EDTA- and K3-EDTA-plasma, Na Citrate and CPDA plasma specimens are acceptable sample types for use with the Elecsys Syphilis assay.

#### Analytical specificity

The analytical specificity of the Elecsys Syphilis assay was determined using human serum samples (single donors, native) spiked with potential cross-reactant antibodies.

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The samples were tested in duplicates on the cobas e 411 Immunoassay Analyzer. The analytical specificity of the assay was determined using 266 human clinical samples from patients with medical conditions unrelated to Syphilis. The 9 samples that were reactive with the Elecsys Syphilis assay were confirmed as co-infected and positive for anti-treponema antibodies with another syphilis total antibody test. No cross-reactivity was found.

| Potential<br>interference | Number<br>tested | Number<br>positive<br>samples |
|---------------------------|------------------|-------------------------------|
| Borrelia | 50 | 0 |
| EBV IgG | 21 | 1 |
| Rubella IgG | 17 | 1 |
| E.coli antibodies | 18 | 1 |
| Hepatitis A | 25 | 1 |
| Hepatitis B | 10 | 2 |
| Hepatitis C | 13 | 0 |
| ANA | 15 | 1 |
| RF | 19 | 0 |
| HSV 1/2 | 12 | 1 |
| CMV IgG | 20 | 0 |
| HIV-1 | 25 | 1 |
| Toxo IgG | 21 | 0 |
| Total | 266 | 9 |

#### 5. CUT-OFF DETERMINATION

In order to define the cut-off for the Elecsys Syphilis assay, native human serum samples were measured with a prototype lot of the Elecsys Syphilis assay and a preliminary cut-off was set.

Next, the comparability in patient samples to commercially available assays was reviewed.

Final validation of the cut-off was done in multi-center studies conducted in the EU and the US.

The classification of samples is as follows:

| Sample result < 1.0 COI | sample is regarded as non-reactive |
|-------------------------|------------------------------------|
| Sample result ≥ 1.0 COI | sample is regarded as reactive |

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#### CLINICAL PERFORMANCE 6.

#### Reproducibility

A reproducibility study was conducted following CLSI EP5-A2 at three sites incorporating a 7 member panel consisting of 5 serum pools (high negative, low positive and moderately positive) and 2 controls that were assayed for 5 days, 2 runs per day, 3 replicates per run. Data from all three sites were combined to achieve SD and percent CV for repeatability (within-run), between run, between-day, between site and reproducibility. The overall reproducibility (imprecision) data are summarized in the following table:

| | | Mean | | Within Run<br>Repeatability | | Between<br>Run | | Between<br>Day | | Between<br>Site | | Reproducibility | | |
|-------------|----|------|------|-----------------------------|------|----------------|------|----------------|------|-----------------|------|-----------------|--------------|------|
| Sample | N | COI | SD | 95% CI | % CV | SD | % CV | SD | % CV | SD | % CV | SD | 95% CI | % CV |
| HSP 06 | 90 | 1.02 | 0.01 | (0.01, 0.01) | 1.16 | 0.02 | 2.28 | 0.00 | 0.00 | 0.01 | 1.29 | 0.03 | (0.02, 0.04) | 2.86 |
| HSP 07 | 90 | 1.13 | 0.02 | (0.02, 0.03) | 1.90 | 0.03 | 2.57 | 0.00 | 0.00 | 0.01 | 0.79 | 0.04 | (0.03, 0.05) | 3.29 |
| HSP 08 | 90 | 0.94 | 0.01 | (0.01, 0.02) | 1.58 | 0.02 | 2.55 | 0.00 | 0.00 | 0.01 | 0.75 | 0.03 | (0.02, 0.04) | 3.09 |
| HSP 09 | 90 | 0.85 | 0.02 | (0.01, 0.02) | 1.88 | 0.02 | 2.49 | 0.00 | 0.00 | 0.01 | 1.23 | 0.03 | (0.02, 0.04) | 3.36 |
| HSP 10 | 90 | 3.24 | 0.09 | (0.08, 0.11) | 2.78 | 0.08 | 2.61 | 0.00 | 0.00 | 0.00 | 0.00 | 0.12 | (0.11, 0.15) | 3.82 |
| SYPH<br>PC1 | 90 | 0.12 | 0.00 | (0.00, 0.00) | 2.41 | 0.00 | 2.39 | 0.00 | 1.15 | 0.01 | 4.47 | 0.01 | (0.00, 0.02) | 5.73 |
| SYPH<br>PC2 | 90 | 4.76 | 0.08 | (0.07, 0.10) | 1.65 | 0.14 | 2.89 | 0.00 | 0.00 | 0.03 | 0.70 | 0.16 | (0.13, 0.21) | 3.40 |

#### Clinical performance in prospective cohorts

A total of 2282 prospectively collected samples of the intended use population were tested at 3 sites using the Elecsys Syphilis assay, including 1524 subjects for routine syphilis testing, 457 HIV positive subjects and 301 pregnant women. In addition, all samples were tested according to a composite algorithm using FDA-cleared tests that included the predicate Syphilis immunoassay, the Rapid Plasma Reagin (RPR) non-treponemal specific assay and the Treponema pallidum Particle Agglutination, treponemal-specific assay.

The following table summarizes the performance of Elecsys Syphilis compared with the final comparator results for all prospective cohorts.

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| | Final Comparator Results | | |
|------------------|--------------------------|-----------------------|-------|
| Elecsys Syphilis | Positive for Syphilis | Negative for Syphilis | Total |
| Reactive | 228 | 16 | 244 |
| Non reactive | 0 | 2038 | 2038 |
| Total | 228 | 2054 | 2282 |

#### Elecsys Syphilis compared with Final Comparator for all prospective cohorts

### Percent agreement by category for prospective cohorts

| Cohort | Positive Percent<br>Agreement | | PPA<br>95 % CI | Negative Percent<br>Agreement | | NPA<br>95 % CI |
|---------------------|-------------------------------|---------|-----------------|-------------------------------|-----------|-----------------|
| | % | Ratio | | % | Ratio | |
| Routine<br>Syphilis | 100 | 66/66 | 94.56 to 100.00 | 99.8 | 1455/1458 | 99.40 to 99.96 |
| HIV | 100 | 162/162 | 97.75 to 100.00 | 95.6 | 282/295 | 92.58 to 97.63 |
| Pregnant | N/A | 0/0 | N/A | 100 | 301/301 | 98.78 to 100.00 |
| Total | 100 | 228/228 | 98.40 to 100.00 | 99.2 | 2038/2054 | 98.74 to 99.55 |

# Clinical performance in retrospective medically diagnosed individuals

Clinical performance in the pre-selected retrospective cohort included a total of 169 specimens, including 15 pregnant positive women and 154 subjects medically diagnosed with syphilis at different stages. The comparison between the Elecsys Syphilis results and the final comparator results is given in the following table.

| | Elecsys Syphilis compared with Final Comparator for retrospective cohorts | | | |
|------------------|---------------------------------------------------------------------------|-----------------------|-------|--|
| | | | | |
| | | | | |
| | Final Comparator Results | | | |
| Elecsys Syphilis | Positive for Syphilis | Negative for Syphilis | Total | |
| Reactive | 155 | 0 | 155 | |
| Non-reactive | 2 | 12 | 14 | |
| Total | 157 | 12 | 169 | |

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| Cohort | Positive Percent<br>Agreement | | PPA<br>95 % CI | Negative Percent<br>Agreement | | NPA<br>95 % CI |
|-----------------------------|-------------------------------|---------|--------------------|-------------------------------|-------|--------------------|
| | % | Ratio | | % | Ratio | |
| Pregnant<br>(Retrospective) | 100 | 15/15 | 78.20 to<br>100.00 | N/A | 0/0 | N/A |
| Staged | 98.6 | 140/142 | 95.00 to 99.83 | 100 | 12/12 | 73.54 to<br>100.00 |
| Overall<br>(Retrospective) | 98.7 | 155/157 | 95.47 to 99.85 | 100 | 12/12 | 73.54 to 99.55 |

### Percent agreement by category for retrospective cohorts

### Clinical performance in pregnant women

A total of 316 pregnant female samples were tested in the study. Of these, 301 were prospectively collected and 15 were retrospectively collected. The percent agreement between the Elecsys Syphilis results and the final comparator results is shown below, stratified by pregnancy trimesters compared with the Composite Algorithm for pregnant women:

| Percent agreement of Elecsys Syphilis with final comparator results for Pregnant Women | | | | |
|----------------------------------------------------------------------------------------|-------------------------------|--------------------|-------------------------------|--------------------|
| Cohort | Positive Percent<br>Agreement | PPA<br>95 % CI | Negative Percent<br>Agreement | NPA<br>95 % CI |
| | % | | % | |
| Pregnant<br>(Prospective) | N/A | N/A | 100 | 98.78 to<br>100.00 |
| 1st Trimester | N/A | N/A | 100 | 96.38 to<br>100.00 |
| 2nd Trimester | N/A | N/A | 100 | 97.09 to<br>100.00 |
| 3rd Trimester | N/A | N/A | 100 | 95.26 to<br>100.00 |
| Pregnant<br>(Retrospective) | 100 | 78.20 to<br>100.00 | N/A | N/A |
| 1st Trimester | 100 | 59.04 to<br>100.00 | N/A | N/A |
| 3rd Trimester | 100 | 63.06 to<br>100.00 | N/A | N/A |
| | Ratio | | Ratio | |
| Pregnant<br>(Prospective) | 0/0 | N/A | 301/301 | |
| 1st Trimester | 0/0 | N/A | 100/100 | |
| 2nd Trimester | 0/0 | N/A | 125/125 | |
| 3rd Trimester | 0/0 | N/A | 76/76 | |
| Pregnant<br>(Retrospective) | 15/15 | | 0/0 | N/A |
| 1st Trimester | 7/7 | | 0/0 | N/A |
| 3rd Trimester | 8/8 | | 0/0 | N/A |

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| Cohort | Positive Percent<br>Agreement | PPA<br>95 % CI | Negative Percent<br>Agreement | NPA<br>95 % CI |
|--------|-------------------------------|----------------|-------------------------------|----------------|
| | % | Ratio | % | Ratio |
| | | 100.00 | | |

### Clinical performance in Medically Diagnosed Individuals

Samples were collected from 154 individuals diagnosed with primary, secondary or latent syphilis. They included 10 females and 144 males. Results of the Elecsys Syphilis assay for this cohort are summarized below.

| Syphilis stage | Treatment status | N | Reactive | Non-reactive |
|--------------------------|------------------|----|----------|--------------|
| Elecsys Syphilis Results | | | | |
| Primary | Treated | 29 | 16 | 13* |
| Primary | Untreated | 25 | 25 | 0 |
| Secondary | Treated | 25 | 24 | 1 |
| Secondary | Untreated | 25 | 25 | 0 |
| Latent | Treated | 25 | 25 | 0 |
| Latent | Untreated | 25 | 25 | 0 |

Reactivity of Elecsys Syphilis in subjects medically diagnosed with syphilis

* 12 of these samples also tested negative for Syphilis with the composite testing algorithm

### Performance in apparently healthy individuals

Specimens were collected from 209 apparently healthy individuals. Of these, 80 were female and 129 male. The results of the Elecsys Syphilis assay for this cohort are shown below

| | Elecsys Syphilis Results | | |
|--------|--------------------------|--------------|-----|
| | Reactive | Non-reactive | |
| | N | N | |
| Female | 9 (11.3 %) | 71 (88.7 %) | 80 |
| Male | 11 (8.5 %) | 118 (91.5 %) | 129 |
| Total | 20 (9.6 %) | 189 (90.4 %) | 209 |

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# Expected values

In this clinical study there were 2282 prospectively collected specimens for the intended use population that were tested with the Elecsys Syphilis assay. There were 244 reactive samples for a 10.7% prevalence of T. pallidum antibodies in the study population. The distribution of the Elecsys Syphilis reactive and non-reactive results is summarized below by age and gender.

| Age Range<br>(years) | | Elecsys Syphilis Results | | |
|----------------------|--------|--------------------------|---------------|-------|
| | Gender | Reactive | Non-reactive | Total |
| 18 21 | Female | 0 (0.00 %) | 247 (100 %) | 247 |
| | Male | 6 (3.5 %) | 165 (96.5 %) | 171 |
| 22 29 | Female | 0 (0.00 %) | 358 (100 %) | 358 |
| | Male | 19 (10.7 %) | 159 (89.3 %) | 178 |
| 30 39 | Female | 10 (3.7 %) | 261 (96.3 %) | 271 |
| | Male | 13 (12.3 %) | 93 (87.7 %) | 106 |
| 40 49 | Female | 29 (12.1 %) | 210 (87.9 %) | 239 |
| | Male | 29 (20.0 %) | 116 (80.0 %) | 145 |
| 50 59 | Female | 47 (20.8 %) | 179 (79.2 %) | 226 |
| | Male | 55 (27.1 %) | 148 (72.9 %) | 203 |
| 60 69 | Female | 11 (23.9 %) | 35 (76.1 %) | 46 |
| | Male | 23 (29.5 %) | 55 (70.5 %) | 78 |
| 70 79 | Female | 0 (0.00 %) | 5 (100 %) | 5 |
| | Male | 2 (22.2 %) | 7 (77.8 %) | 9 |
| Combined | Total | 244 (10.7 %) | 2038 (89.3 %) | 2282 |

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#### CONCLUSIONS 7.

There was good agreement between the Elecsys Syphilis assay and the results from the final comparator algorithm.

A comparison of the device features, intended use, non-clinical and clinical data supports a decision that Elecsys Syphilis is substantially equivalent to the predicate assay.