(90 days)
For the qualitative determination of total (IgG and IgM) antibodies to Treponema pallidum (TP) specific antigens in human serum and plasma using the VITROS 5600 Integrated System.
The presence of antibodies to Treponema pallidum (TP) specific antigens, in conjunction with non-treponemal laboratory tests and clinical findings may aid in the diagnosis of syphilis infection.
The VITROS Syphilis test is not intended for blood and tissue donor screening.
The VITROS Immunodiagnostic Products Syphilis test is performed using the VITROS Immunodiagnostic Products Syphilis Reagent Pack and VITROS Immunodiagnostic Products Syphilis Calibrator on the VITROS 5600 Integrated System.
An immunometric technique is used; this involves a two-stage reaction. In the first stage antibodies to Syphilis TP specific antigens present in the sample bind with biotinylated recombinant Syphilis TP antigens immobilized on streptavidin coated wells. Unbound sample is removed by washing. In the second stage conjugate reagent containing horseradish peroxidase (HRP)-labeled recombinant Syphilis TP antigens is added. The conjugate binds specifically to any antibody to Syphilis TP specific antigens captured on the well in the first stage. Unbound conjugate is removed by washing.
The bound HRP conjugate is measured by a luminescent reaction. A reagent containing luminogenic substrates (a luminol derivative and a peracid salt) and an electron transfer agent is added to the wells. The HRP in the bound conjugate catalyzes the oxidation of the luminol derivative, producing light. The electron transfer agent (a substituted acetanilide) increases the level of light produced and prolongs its emission. The light signals are read by the system.
Here's a detailed breakdown of the acceptance criteria and the study proving the device meets these criteria, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implied by the clinical performance results meeting high percentage agreements. While explicit numeric acceptance criteria (e.g., "PPA must be >X%") are not directly stated in a dedicated section, the sponsor presents the results and concludes substantial equivalence, indicating that these results were considered acceptable.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| All Prospective Subgroups | ||
| Positive Percent Agreement (PPA) | High agreement with comparator | 99.5% (218/219) |
| Negative Percent Agreement (NPA) | High agreement with comparator | 97.6% (688/705) |
| Routine Syphilis (Prospective) | ||
| PPA | High agreement with comparator | 98.8% (83/84) |
| NPA | High agreement with comparator | 99.2% (527/531) |
| Pregnant Women (Prospective) | ||
| PPA | High agreement with comparator | 100.0% (1/1) |
| NPA | High agreement with comparator | 97.8% (45/46) |
| HIV Positive (Prospective) | ||
| PPA | High agreement with comparator | 100.0% (134/134) |
| NPA | High agreement with comparator | 90.6% (116/128) |
| All Retrospective Specimens | ||
| PPA | High agreement with comparator | 100.0% (213/213) |
| NPA | High agreement with comparator | 98.8% (330/334) |
| Pregnant Women (Retrospective) | ||
| PPA | High agreement with comparator | 100.0% (31/31) |
| NPA | High agreement with comparator | 100.0% (212/212) |
| HIV Positive (Retrospective) | ||
| PPA | High agreement with comparator | 100.0% (30/30) |
| NPA | High agreement with comparator | 96.7% (118/122) |
| Pre-selected Positive (Retrospective) | ||
| PPA | High agreement with comparator | 100.0% (152/152) |
| NPA | N/A (denominator is zero) | N/A |
| Medically Diagnosed (Syphilis) Reactivity | Consistent detection | 100% reactive (151/151) across all stages and treatment statuses |
| Apparently Healthy Individuals Reactivity | Low false positive rate | 2.0% reactive (4/201), with 3 of these confirmed positive by final comparator |
2. Sample size used for the test set and the data provenance
- Test Set Sample Size:
- Prospective Specimens: 924 total specimens.
- 615 subjects for routine syphilis testing (from 6 sites in the United States).
- 47 pregnant women.
- 262 HIV positive subjects.
- Retrospective Specimens: 547 total specimens.
- 243 samples from pregnant women.
- 152 HIV positive samples.
- 152 pre-selected positive samples.
- Medically Diagnosed Individuals: 151 samples.
- Apparently Healthy Individuals: 201 prospective specimens (from 3 sites in the United States).
- Total Clinical Samples: 924 (prospective) + 547 (retrospective) + 201 (apparently healthy) = 1672 specimens for primary clinical evaluation. The medically diagnosed group is a subset likely included within the prospective/retrospective groups or as additional targeted samples.
- Prospective Specimens: 924 total specimens.
- Data Provenance:
- Country of Origin: United States (for prospective and apparently healthy specimens). Retrospective samples are "purchased," implying they may originate from various sources but were tested at sites.
- Retrospective or Prospective: Both retrospective and prospective clinical studies were conducted.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
The document does not specify the number of experts or their qualifications for establishing the ground truth. Instead, the ground truth was established using a "composite testing algorithm."
4. Adjudication method for the test set
The adjudication method relied on a composite testing algorithm using:
- A treponemal electrochemiluminescence immunoassay (TP-ECLIA)
- A Rapid Plasma Reagin (RPR) non-treponemal assay
- A Treponema pallidum Particle Agglutination (TP-PA) Treponema-specific assay
Cases were categorized as "Positive for Syphilis" or "Negative for Syphilis" based on the results of these FDA-cleared comparator assays. The document describes specific combinations of results from these three assays that led to a final comparator result. For example, "Non-reactive TP-ECLIA + Non-reactive RPR" was deemed "Negative," while "Reactive TP-ECLIA + Reactive RPR (and N/A TP-PA)" was "Positive." Discordant results with the final comparator were further analyzed (e.g., 14 discordant prospective samples were found reactive by another FDA-cleared TP antibody test).
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
No, an MRMC comparative effectiveness study involving human readers and AI assistance was not conducted or reported. This device is an in vitro diagnostic test (IVD) for laboratory use, not an AI-powered image analysis or diagnostic aid for human readers.
6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done
Yes, the studies presented are standalone performance evaluations of the VITROS Immunodiagnostic Products Syphilis test (an algorithm-driven instrument/reagent system) without human-in-the-loop performance being a variable in the reported clinical accuracy. The assay itself performs the determination.
7. The type of ground truth used
The ground truth used was a composite testing algorithm based on multiple FDA-cleared comparator assays (TP-ECLIA, RPR, and TP-PA). This is a form of clinical surrogate ground truth derived from established diagnostic tests, rather than direct pathology, biopsy, or long-term outcomes data, which are typically used for definitive diagnosis in some other medical fields.
8. The sample size for the training set
The document does not provide information on the sample size for a training set. This is because the device described is an immunoassay, a biochemical test, not a machine learning or AI algorithm that typically requires a separate training set. The reported studies evaluate the locked-down analytical and clinical performance of the manufactured diagnostic kit.
9. How the ground truth for the training set was established
Since there is no training set mentioned for an AI/machine learning algorithm, the concept of establishing ground truth for a training set is not applicable here. The assay's internal calibration and optimization would have been performed during product development, but this is distinct from "training" an AI model in the context of imaging or predictive analytics.
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Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.
August 28, 2024
Ortho Clinical Diagnostics Rebecca Lewis Senior Regulatory Affairs Associate Felindre Meadows Pencoed Bridgend, CF35 5PZ United Kingdom
Re: K241534
Trade/Device Name: VITROS Immunodiagnostic Products Syphilis Reagent Pack Regulation Number: 21 CFR 866.3830 Regulation Name: Treponema Pallidum Treponemal Test Reagents Regulatory Class: Class II Product Code: LIP Dated: May 30, 2024 Received: May 30, 2024
Dear Rebecca Lewis:
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 (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. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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.
Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device"
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(https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30. Design controls; 21 CFR 820.90. Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review. the OS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
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 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safetyreporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely. Himani Bisht -S
Himani Bisht, Ph.D Assistant Director Viral Respiratory and HPV Branch Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics Office of Product Evaluation and Quality Center for Devices and Radiological Health
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Enclosure
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Indications for Use
510(k) Number (if known) K241534
Device Name
VITROS Immunodiagnostic Products Syphilis Reagent Pack (VITROS Syphilis test)
Indications for Use (Describe)
VITROS Immunodiagnostic Products Syphilis Reagent Pack (VITROS Syphilis test)
For the qualitative determination of total (IgG and IgM) antibodies to Treponema pallidum (TP) specific antigens in human serum and plasma using the VITROS 5600 Integrated System.
The presence of antibodies to Treponema pallidum (TP) specific antigens, in conjunction with non-treponemal laboratory tests and clinical findings may aid in the diagnosis of syphilis infection.
The VITROS Syphilis test is not intended for blood and tissue donor screening.
Type of Use (Select one or both, as applicable)X Prescription Use (Part 21 CFR 801 Subpart D)
| Over-The-Counter Use (21 CFR 801 Subpart C)
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510(k) Summary
This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92. The assigned 510(k) number is: K241534.
Submitter's Information
Ortho Clinical Diagnostics
Felindre Meadows,
Pencoed,
UK CF35 5PZ Phone: +44 (0) 7971 427649
Fax: 585-453-4110 Contact Person: Rebecca Lewis
Preparation Date
August 27, 2024
Device Proprietary Name(s)
VITROS Immunodiagnostic Products Syphilis Reagent Pack
Common Name(s) VITROS Syphilis test
Classification Names
| Product Code | Class | Regulation Section | Panel |
|---|---|---|---|
| LIP | II | 21 CFR 866.3830Division of Microbiology Devices (DMD) | Microbiology |
Predicate Device(s)
| Predicate Device | FDA 510(k) Number |
|---|---|
| Elecsys Syphilis | K160910 & K211302 |
Device Description
The VITROS Immunodiagnostic Products Syphilis test is performed using the VITROS Immunodiagnostic Products Syphilis Reagent Pack and VITROS Immunodiagnostic Products Syphilis Calibrator on the VITROS 5600 Integrated System.
An immunometric technique is used; this involves a two-stage reaction. In the first stage antibodies to Syphilis TP specific antigens present in the sample bind with biotinylated recombinant Syphilis TP antigens immobilized on streptavidin coated wells. Unbound sample is removed by washing. In the second stage conjugate reagent containing horseradish peroxidase (HRP)-labeled recombinant Syphilis TP antigens is added. The conjugate binds specifically to any antibody to Syphilis TP specific antigens captured on the well in the first stage. Unbound conjugate is removed by washing.
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The bound HRP conjugate is measured by a luminescent reaction. A reagent containing luminogenic substrates (a luminol derivative and a peracid salt) and an electron transfer agent is added to the wells. The HRP in the bound conjugate catalyzes the oxidation of the luminol derivative, producing light. The electron transfer agent (a substituted acetanilide) increases the level of light produced and prolongs its emission. The light signals are read by the system.
VITROS Immunodiagnostic Products Syphilis Reagent Pack contains:
1 reagent pack containing:
- 100 coated wells; biotin-recombinant Syphilis TP antigens, 0.15 ug/mL. ●
- 13.1 mL assay reagent (buffer with bovine gamma globulin, bovine serum albumin and antimicrobial agent).
- 20.4 mL conjugate reagent (HRP-recombinant Syphilis TP antigens, 0.15 µg/mL) in buffer with bovine serum albumin and antimicrobial agent.
VITROS Syphilis Calibrator contains:
- 1 vial of VITROS Syphilis Calibrator (human anti-Syphilis TP antigen in anti-Syphilis ● TP antigen negative human plasma with antimicrobial agent, 2.2 mL).
Intended Use Statement(s):
VITROS Immunodiagnostic Products Syphilis Reagent Pack (VITROS Syphilis test) For the qualitative determination of total (IgG and IgM) antibodies to Treponema pallidum (TP) specific antigens in human serum and plasma using the VITROS 5600 Integrated System.
The presence of antibodies to Treponema pallidum (TP) specific antigens, in conjunction with non-treponemal laboratory tests and clinical findings may aid in the diagnosis of syphilis infection.
The VITROS Syphilis test is not intended for blood and tissue donor screening.
Comparison to Predicate Devices
The following table provides a summary of the key features of the new device assessed against the predicate.
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| Device Characteristic | Predicate Device | New Device |
|---|---|---|
| Roche Elecsys Syphilis assay,K160910 and K211302, cleared 28July 2016 and 20 July 2021 | VITROS Immunodiagnostic ProductsSyphilis Reagent Pack | |
| Intended Use | For the in vitro qualitative detection of totalantibodies (IgGand IgM) to Treponema pallidum in human serum and plasma.The test is intended as an aid in the diagnosisof syphilis infection in conjunction withclinical signs and symptoms.The Elecsys Syphilis immunoassay is notintended for use in screening blood or tissuedonors. The effectiveness of this assay intesting blood or tissue donors has not beenestablished.The electrochemiluminescence immunoassay"ECLIA" is intended for useon cobas e immunoassay analyzers. | VITROS Immunodiagnostic Products SyphilisReagent Pack (VITROS Syphilis test)For the qualitative determination of total (IgGand IgM) antibodies to Treponema pallidum(TP) specific antigens in human serum andplasma using the VITROS 5600 IntegratedSystem.The presence of antibodies to Treponemapallidum (TP) specific antigens, in conjunctionwith non-treponemal laboratory tests and clinicalfindings may aid in the diagnosis of syphilisinfection.The VITROS Syphilis test is not intended forblood and tissue donor screening. |
| Basic Principle | Sandwich immunoassay. | Same. |
| Analyte | Anti-Syphilis TPA. | Same. |
| Sample Type | Serum and Plasma. | Same. |
| Automated | Automated assay. | Same. |
| Measurement | Qualitative. | Same. |
| Interpretation ofresults | Samples with a cutoff index < 1.00 arenon-reactive. These samples are considerednegative for anti-Treponema pallidumantibodies.Samples with a cutoff index ≥ 1.00 areconsidered reactive. | Same. |
General Device Characteristic Differences:
| Traceability | N/A. | Traceable to an in-house reference calibratorwhich has been value assigned to optimizeclinical sensitivity and specificity. |
|---|---|---|
| Sample Volume | 6 µL. | 25 µL. |
| Calibrator Levels | 2. | 1. |
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VITROS Immunodiagnostic Products Syphilis Reagent Pack Traditional 510(k)
Nonclinical Performance
Several nonclinical tests were performed.
Stability Studies
Long term stability and on-board storage performance was evaluated consistent with methods based on CLSI EP25-A.
Long Term Stability: Four runs have been performed on each of 3 Lots at each time-point, monthly intervals, will support a 52 week shelf-life. All results were acceptable and support a claim of 21 weeks stability currently.
On-board Stability: Three Lots of the VITROS Immunodiagnostic Products Syphilis reagent pack were stored opened refrigerated for up to 13 weeks. Four runs were performed on each Lot at each time-point for fresh and open, all results were acceptable and support a claim of 12 weeks on-board stability.
Result Calculation
Result = Signal for test sample Signal at Cutoff (Cutoff value)
Interpretation of results
Samples with results less than 1.00 will be flagged as "Non-reactive" and samples with results greater than or equal to 1.00 will be flagged as "Reactive".
| VITROS Syphilis TestResult (S/C) | Status | Interpretation |
|---|---|---|
| < 1.00 | Non-reactive | Indicates no active or previousinfection with Treponemapallidum. |
| ≥ 1.00 | Reactive | Indicates active or previousinfection with Treponemapallidum. |
Note: The results from this or any other diagnostic test should be used and interpreted only in the context of the overall clinical picture. A Non-reactive test result does not exclude the possibility of recent exposure to Treponema pallidum. Levels of anti-T.pallidum antibodies may be below the cutoff in early infection.
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VITROS Immunodiagnostic Products Syphilis Reagent Pack Traditional 510(k)
Precision
The within-laboratory precision of the VITROS Syphilis test was evaluated with five serum pools (PP) following CLSI document EP05. 15 Two reagent lots and calibrator lots were included in the study. For each reagent lot, operators ran two replicates of each precision pool on two occasions per day for 20 non-consecutive days.
The data presented are a representation of assay performance and are provided as a guideline. Variables such as sample handling and storage, reagent handling and storage, laboratory environment, and system maintenance can affect reproducibility of assay results.
| PanelMember | No.of | %Reactive | Grand | Repeatability*(Within Run) | Between-Run | Between-Day | Between-Lot | Within-Laboratory** | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Obs | Mean | SD | CV(%) | SD | CV(%) | SD | CV(%) | SD | CV(%) | SD | CV(%) | ||
| HumanSerumPool, Non-reactive | 160 | 0% (0/160) | 0.02 | 0.003 | - | 0.001 | - | 0.001 | - | 0.002 | - | 0.004 | - |
| HumanSerumPool, HighNon-reactive | 160 | 0% (0/160) | 0.72 | 0.016 | 2.2 | 0.040 | 5.5 | 0.015 | 2.1 | 0.127 | 17.7 | 0.135 | 18.8 |
| HumanSerumPool, LowReactive | 160 | 100%(160/160) | 1.27 | 0.026 | 2.0 | 0.053 | 4.2 | 0.038 | 3.0 | 0.199 | 15.7 | 0.211 | 16.6 |
| HumanSerumpool,Reactive | 160 | 100%(160/160) | 2.16 | 0.041 | 1.9 | 0.064 | 2.9 | 0.062 | 2.8 | 0.300 | 13.9 | 0.315 | 14.6 |
| HumanSerumPool.Reactive | 160 | 100%(160/160) | 7.70 | 0.130 | 1.7 | 0.080 | 1.0 | 0.220 | 2.8 | 0.889 | 11.5 | 0.928 | 12.0 |
Product Claim
Repeatability was determined using two replicates per run.
4 Within-Laboratory precision variability contains the Within Run, Between Ray and Between Lot variance components using two individual reagent lots with a single calibration for each reagent lot.
Reproducibility
A five-level reproducibility panel was tested with one lot of reagents at three sites, twice a day, with two unique operators a day, three replicates per run, for a total of five testing days. The repeatability (within day), between run/operator, between site, and reproducibility (total) precision estimates (CV (%)) derived from a variance component analysis are summarized below.
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| MeanVITROS | Repeatabilitya(Within Run) | BetweenRun/Operatorb | Between Dayc | Between Sited | Reproducibilitye | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Panel Description | SyphilisResults (S/C) | SD | CV(%) | SD | CV(%) | SD | CV(%) | SD | CV(%) | SD | CV(%) | N |
| Human SerumPool, Non-reactive | 0.02 | 0.003 | - | 0.000 | - | 0.002 | - | 0.005 | - | 0.006 | - | 90 |
| Human SerumPool, High Non-reactive | 0.75 | 0.021 | 2.8 | 0.018 | 2.4 | 0.019 | 2.5 | 0.015 | 2.0 | 0.037 | 4.9 | 90 |
| Human SerumPool, LowReactive | 1.29 | 0.036 | 2.8 | 0.024 | 1.9 | 0.038 | 3.0 | 0.024 | 1.8 | 0.062 | 4.9 | 90 |
| Human SerumPool, Reactive | 2.14 | 0.048 | 2.2 | 0.030 | 1.4 | 0.047 | 2.2 | 0.047 | 2.2 | 0.088 | 4.1 | 90 |
| Human SerumPool, Reactive | 7.42 | 0.145 | 2.0 | 0.000 | 0.0 | 0.080 | 1.1 | 0.246 | 3.3 | 0.297 | 4.0 | 90 |
Product Claim
ª Repeatability: Variability of the VITROS Syphilis test performance within day replicate, calculated using data across all sites.
b Between Run/Operator: Variability of the VITROS Syphilis test performance from run to run, calculated using data across all sites.
& Between Day: Variability of the VITROS Syphilis test performance from day to day, calculated using data across all sites.
d Between site: Variability of the VITROS Syphilis test performance from site to site.
e Reproducibility (Total): Variability of the test incorporating factors of repeatability, between day, and between site.
Matrix Comparison
Serum and plasma (Heparin and EDTA) specimen matrices were determined to be equivalent. The results met the acceptance criteria for the comparison between serum and plasma (Heparin and EDTA) specimens spanning the expected measuring interval. Based on the analysis, serum and plasma (Heparin and EDTA) are suitable specimen matrices for use with the VITROS Immunodiagnostic Products Syphilis test.
Specimens Recommended
Verified specimen types to be used with this test:
- Serum .
- Serum Separator Tube (SST) .
- Plasma Separator Tube (PST) ●
- Lithium heparin plasma ●
- Sodium heparin plasma ●
- K2 EDTA plasma ●
- K3 EDTA plasma .
Specimens Not Recommended
- Do not use turbid specimens. Turbidity in specimens may affect test results.
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Sample Stability Studies
Samples were collected from in-house donors in the following tube types: serum, serum separator tubes (SST), LiHep plasma separator tubes (PST), lithium heparin (LiHep) plasma, sodium heparin (NaHep) plasma, K2 EDTA plasma and K3 EDTA plasma and were evaluated at room temperature (30 degrees Celsius), refrigerated (2 - 8 degrees Celsius), and frozen (minus 20 degrees Celsius) storage conditions. All samples were tested at every time point and storage condition. Room temperature time points included 24 hours and 7 days. Refrigerated time points included 3 and 7 days. Frozen time points included 7 days, 28 days and 28 days with five freeze-thaw cycles.
Ortho is claiming the following storage conditions for specimens.
Serum, Serum (SST), Serum (PST), Plasma (PST), Li-Heparin, K2 EDTA and K3EDTA at:
2 to 8°C for 7 days Room temperature for 7 days Frozen for 28 days Samples may be frozen and thawed up to 5 times.
Carryover
A carryover study was executed which verified that the VITROS Immunodiagnostic Products Syphilis test is not affected by sample carry over.
Detection of Syphilis IgG and IgM
A study was conducted to evaluate the ability of the VITROS Immunodiagnostic Products Syphilis test to detect Syphilis TPA specific IgM and IgG antibodies. The VITROS Immunodiagnostic Products Syphilis reagent pack is capable of specifically detecting syphilis IgG and IgM antibodies.
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Analytical Specificity
Substances that do not Interfere
The VITROS Syphilis test was evaluated for potential interference consistent with CLSI documents EP07 to and EP37. 17 Commonly encountered substances were tested using two lots of reagents. Of the compounds tested, none was found to interfere with the clinical interpretation of the assay at the concentrations indicated when tested in negative and weakly reactive samples.
| Concentration | ||
|---|---|---|
| Substance | Conventional Units | SI Units |
| Acetaminophen | 15.6 mg/dL | 1030 µmol/L |
| Acetylcysteine | 15 mg/dL | 920 µmol/L |
| Acetylsalicylic Acid | 3.0 mg/dL | 167 µmol/L |
| Ampicillin-Na | 7.5 mg/dL | 215 µmol/L |
| Ascorbic Acid | 30.6 mg/dL | 1738 µmol/L |
| Bilirubin (conjugated) | 40.0 mg/dL | 475 µmol/L |
| Bilirubin (unconjugated) | 40.0 mg/dL | 684 µmol/L |
| Biotin | 3510 ng/mL | 14.3 µmol/L |
| Cefoxitin | 660 mg/dL | 15500 µmol/L |
| Cholesterol | 400 mg/dL | 10.3 mmol/L |
| Cyclosporine | 0.18 mg/dL | 1.50 µmol/L |
| Doxycyclin | 18 mg/L | 40.5 µmol/L |
| Hemoglobin | 1000 mg/dL | 10 g/L |
| Heparin | 330 U/dL | 330 units/dL |
| Human anti-mouse Antibodies(HAMA) | 5120 ng/mL | N/A |
| Ibuprofen | 21.9 mg/dL | 1060 µmol/L |
| Human IgG | 2894 mg/dL | N/A |
| Intralipid | 2000 mg/dL | NA |
| Levodopa | 0.75 mg/dL | 38 µmol/L |
| Methyldopa | 2.25 mg/dL | 107 µmol/L |
| Metronidazole | 123 mg/L | 7190 µmol/L |
| Phenylbutazone | 32.1 mg/dL | 1040 µmol/L |
| Total Protein | 15 g/dL | 150 g/L |
| Rheumatoid Factor | 2941 IU/mL | N/A |
| Rifampicin | 4.8 mg/dL | 58.3 µmol/L |
| Sodium Azide | 20 mg/dL | 3076 µmol/L |
| Theophylline | 60 mg/L | 333 µmol/L |
| Triglycerides | 1500 mg/dL | 16.94 mmol/L |
NA = Not Applicable (alternate units not provided)
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Cross-Reactivity
The cross-reactivity of the VITROS Immunodiagnostic Products Syphilis test was evaluated for potential cross-reactivity in anti-syphilis TP negative samples from medical conditions unrelated to syphilis infection. The results are summarized in the table below.
| Sample Category | Number of Samples | Non-reactive | Reactive |
|---|---|---|---|
| Anti-nuclear antibodies (ANA) | 10 | 10 | 0 |
| Borrelia burgdorferi infection IgG (European and US strains) | 10 | 10 | 0 |
| Cytomegalovirus (anti-CMV IgG positive and IgM positive) | 10 | 10 | 0 |
| Epstein-Barr Virus (EBV IgG positive and IgM positive) | 10 | 10 | 0 |
| Hepatitis A (HAV) IgG and IgM | 10 | 10 | 0 |
| Hepatitis B (HBV) IgG and IgM | 10 | 10 | 0 |
| Hepatitis C (HCV) IgG and IgM | 10 | 10 | 0 |
| Herpes Simplex Virus 1/2 (anti-HSV-1/2 IgG positive and IgM positive) | 10 | 10 | 0 |
| Human Immunodeficiency Virus (HIV 1/2) IgG and IgM | 12 | 10 | 2* |
| Rheumatoid Arthritis/Rheumatoid Factor | 10 | 10 | 0 |
| Rubella IgG and IgM | 10 | 10 | 0 |
| Hyperglobulinemia | 10 | 10 | 0 |
| Systemic Lupus Erythematosus (SLE) | 10 | 10 | 0 |
| Toxoplasmosis IgG positive and IgM positive | 10 | 10 | 0 |
| Varicella-Zoster Virus (VZV IgG positive) | 15 | 10 | 5* |
| E. coli antibodies | 10 | 10 | 0 |
| Leptospirosis | 10 | 10 | 0 |
| VCA (EBV Viral Capsid Antigen) IgM | 10 | 10 | 0 |
- The 7 samples that were reactive with the VITROS Syphilis test were confirmed as coinfected and positive for anti-Treponema pallidum antibodies with another syphilis total antibody assay. No crossreactivity was observed.
Limitations of the Procedure
- A reactive test result for treponemal antibodies is not diagnostic of syphilis without additional serologic testing and a full clinical evaluation.
- . False reactive results can be expected with any test kit. The proportion of these falsely reactive specimens is dependent upon the specificity of the test kit, specimen integrity, and the characteristics of the local population being screened.
- Results in samples from immunosuppressed patients or from patients with disorders leading to ●
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VITROS Immunodiagnostic Products Syphilis Reagent Pack Traditional 510(k)
immunosuppression should be interpreted with caution.
- The detection of treponemal antibodies may indicate recent, past, or successfully treated ● syphilis. This test cannot distinguish between active and treated infection, and therefore may not be used to determine response to therapy, relapse, or reinfection.
- Assay interference due to circulating antibodies against yaws, pinta, and bejel has not been evaluated. Cross-reactivity with these treponemal disease conditions is to be expected with treponemal antibody tests.
- A Non-reactive test result does not completely rule out the possibility of an infection with ● Treponema pallidum. Serum or plasma samples from the very early (pre-seroconversion) phase or the late phase of a syphilis infection can occasionally vield negative findings.
- . Heterophilic antibodies in serum or plasma samples may cause interference in immunoassays. These antibodies may be present in blood samples from individuals regularly exposed to animals or who have been treated with animal serum products. Results which are inconsistent with clinical observations indicate the need for additional testing.
- Certain drugs and clinical conditions are known to alter antibody concentrations in vivo. For additional information, refer to one of the published summaries.
- Do not use quality control materials preserved with azide.
Traceability of Calibration
Calibration of the VITROS Immunodiagnostic Products Syphilis reagent pack is traceable to an in-house reference calibrator which has been value assigned to optimize clinical sensitivity and specificity.
Clinical Studies
Clinical Performance in Prospectively Collected Specimens
A total of 924 prospective specimens from the intended use population collected from 6 sites in the United States were tested at 3 sites using the VITROS Syphilis test, including 615 subjects sent for routine syphilis testing, 47 pregnant women and 262 HIV positive subjects. In addition, all samples were tested according to a composite testing algorithm using FDA-cleared tests that included a treponemal electrochemiluminescence immunoassay (TP-ECLIA), a Rapid Plasma Reagin (RPR) non-treponemal assay and aTreponema pallidum Particle Agglutination (TP-PA) Treponema-specific assay.
A summary of the serological test profile for all prospectively collected specimens in the intended use population is presented in the following table.
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| TP-ECLIAResult | RPRResult | TP-PAResult | FinalComparatorResult | VITROSSyphilis Result | Number ofSubjects |
|---|---|---|---|---|---|
| Non-reactive | Non-reactive | N/A* | Negative | Non-reactive | 684 |
| Reactive | 2 | ||||
| Non-reactive | Reactive | Reactive | Positive | Non-reactive | 1 |
| Reactive | 0 | ||||
| Non-reactive | Reactive | Non-reactive | Negative | Non-reactive | 2 |
| Reactive | 1 | ||||
| Non-reactive | Reactive | Inconclusive | Negative | Non-reactive | 0 |
| Reactive | 0 | ||||
| Reactive | Reactive | N/A* | Positive | Non-reactive | 0 |
| Reactive | 84 | ||||
| Reactive | Reactive | Reactive | Positive | Non-reactive | 0 |
| Reactive | 129 | ||||
| Reactive | Non-reactive | Non-reactive | Negative | Non-reactive | 2 |
| Reactive | 14 | ||||
| Reactive | Non-reactive | Inconclusive | Positive | Non-reactive | 0 |
| Reactive | 5 |
Serological Test Profile for the Prospective Intended Use Population
- N/A = Test not performed
The comparison between the VITROS Syphilis results and the final comparator results for the prospective specimens in the intended use population is shown in the following table.
VITROS Syphilis Test Results Compared with Final Comparator for the Prospective Intended Use Population
| VITROSSyphilis | Final Comparator Results | Total | |
|---|---|---|---|
| Positive for Syphilis | Negative for Syphilis | ||
| Reactive | 218 | 17 | 235 |
| Non-reactive | 1 | 688 | 689 |
| Total | 219 | 705 | 924 |
The positive percent agreement (PPA) and the negative percent agreement (NPA) between the VITROS Syphilis results and the final comparator results for each subgroup of the prospectively collected specimens in the intended use population are summarized in the following table.
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| Subgroup | PPA% (n/N) | 95% CI*(%) | NPA% (n/N) | 95% CI*(%) |
|---|---|---|---|---|
| Routine Syphilis** | 98.8(83/84) | 93.6 - 99.8 | 99.2(527/531)*** | 98.1 - 99.7 |
| Pregnant Women | 100.0(1/1) | 20.7 - 100.0 | 97.8(45/46)*** | 88.7 - 99.6 |
| HIV Positive | 100.0(134/134) | 97.2 - 100.0 | 90.6(116/128)*** | 84.3 - 94.6 |
| All ProspectiveSubgroups | 99.5(218/219) | 97.5 - 99.9 | 97.6(688/705)*** | 96.2 - 98.5 |
Percent Agreement by Category for the Prospective Intended Use Population
*95% Wilson score confidence interval
** Does not include prospectively collected Pregnant Women and HIV Positive specimens
*** Of the 17 discordant samples that were negative by the Final Comparator, 14 samples (2 routine Syphilis, 1 pregnancy, 1 HIV positive) were reactive by a FDA cleared Treponema pallidum antibody test.
Clinical Performance in Retrospective Specimens
A total of 547 retrospective purchased samples were tested at 3 sites using the VITROS Syphilis test, including 243 samples from pregnant women, 152 HIV positive samples and 152 pre-selected positive samples. In addition, all samples were tested according to a composite testing algorithm using FDA-cleared tests that included treponemal electrochemiluminescence immunoassay (TP-ECLIA), a Rapid Plasma Reagin (RPR) non-treponemal specific assay and a Treponema-pallidum Particle Agglutination (TP-PA) Treponema-specific assay.
The comparison between the VITROS Syphilis results and the final comparator results for the retrospective specimens is shown in the following table.
VITROS Syphilis Test Results Compared with Final Comparator for the Retrospective Specimens
| VITROSSyphilis | Final Comparator Results | Total | |
|---|---|---|---|
| Positive for Syphilis | Negative for Syphilis | ||
| Reactive | 213 | 4 | 217 |
| Non-reactive | 0 | 330 | 330 |
| Total | 213 | 334 | 547 |
The PPA and the NPA between the VITROS Syphilis results and the final comparator results for each subgroup of the retrospective specimens are summarized in the following table.
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| Subgroup | PPA% (n/N) | 95% CI*(%) | NPA% (n/N) | 95% CI*(%) |
|---|---|---|---|---|
| Pregnant Women | 100.0(31/31) | 89.0 - 100.0 | 100.0(212/212) | 98.2 - 100.0 |
| HIV Positive | 100.0(30/30) | 88.6 - 100.0 | 96.7(118/122)** | 91.9 - 98.7 |
| Pre-selected Positive | 100.0(152/152) | 97.5 - 100.0 | N/A *** | N/A *** |
Percent Agreement by Category for the Retrospective Specimens
*95% Wilson score confidence interval
** Four discordant samples that were negative by the Final Comparator were reactive by a FDA cleared Treponema pallidum antibody test.
***N/A = Not applicable, denominator is zero
Clinical Performance in Pregnant Women
Samples from 290 pregnant women were tested in the study. Of these samples, 47 were prospectively collected and 243 were retrospective samples. The percent agreement between the VITROS Syphilis results and the final comparator results is shown below stratified by pregnancy trimesters.
Percent Agreement for the Pregnant Women Population
| Pregnant Women | PPA% (n/N) | 95% CI*(%) | NPA% (n/N) | 95% CI*(%) |
|---|---|---|---|---|
| Prospectively Collected Specimens | ||||
| First Trimester | 100.0(1/1) | 20.7 - 100.0 | 96.0(24/25)** | 80.5 - 99.3 |
| Second Trimester | N/A*** | N/A*** | 100.0(19/19) | 83.2 - 100.0 |
| Third Trimester | N/A*** | N/A*** | 100.0(2/2) | 34.2 - 100.0 |
| Overall Prospectively CollectedSpecimens | 100.0(1/1) | 20.7 - 100.0 | 97.8(45/46)** | 88.7 - 99.6 |
| Retrospective Specimens | ||||
| First Trimester | N/A*** | N/A*** | 100.0(42/42) | 91.6 - 100.0 |
| Second Trimester | 100.0(31/31) | 89.0 - 100.0 | 100.0(102/102) | 96.4 - 100.0 |
| Third Trimester | N/A*** | N/A*** | 100.0(68/68) | 94.7 - 100.0 |
| Overall RetrospectiveSpecimens | 100.0(31/31) | 89.0 - 100.0 | 100.0(212/212) | 98.2 - 100.0 |
*95% Wilson score confidence interval
** One discordant sample that was negative by the Final Comparator was reactive by a FDA cleared Treponema pallidum antibody test. ***N/A = Not applicable, denominator is zero
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Clinical Performance in HIV Positive Individuals
Samples from 414 HIV positive individuals were tested in the study. Of these samples, 262 were prospectively collected and 152 were retrospective samples. The percent agreement between the VITROS Syphilis results and the final comparator results is shown below.
Percent Agreement for the HIV Positive Population
| HIV Positive Specimens | PPA% (n/N) | 95% CI*(%) | NPA% (n/N) | 95% CI*(%) |
|---|---|---|---|---|
| Prospectively Collected Specimens | 100.0(134/134) | 97.2 - 100.0 | 90.6(116/128)** | 84.3 - 94.6 |
| Retrospective Specimens | 100.0(30/30) | 88.6 - 100.0 | 96.7(118/122)** | 91.9 - 98.7 |
*95% Wilson score confidence interval
** Of the 16 discordant samples that were negative by the Final Comparator, 15 samples (11 prospective) were reactive by a FDA cleared Treponema pallidum antibody test.
Clinical Performance in Medically Diagnosed Individuals
A total of 151 samples from individuals medically diagnosed with Syphilis were tested in the study. Reactivity of specimens with primary, secondary, and latent syphilis by treatment status is summarized in the table below.
VITROS Syphilis Reactivity in the Medically Diagnosed Population
| SyphilisStage | TreatmentStatus | N | VITROS Syphilis ResultsReactive |
|---|---|---|---|
| Primary | Treated | 25 | 25 |
| Primary | Untreated | 25 | 25 |
| Secondary | Treated | 25 | 25 |
| Secondary | Untreated | 25 | 25 |
| Latent | Treated | 25 | 25 |
| Latent | Untreated | 26 | 26 |
Clinical Performance in Apparently Healthy Individuals
A total of 201 prospective specimens from apparently healthy individuals collected from 3 sites in the United States were tested at 3 sites using the VITROS Syphilis test. Reactivity of specimens acquired from apparently healthy individuals is summarized in the table below.
VITROS Syphilis Reactivity in the Apparently Healthy Population
| Category | N | VITROS Syphilis Result | |
|---|---|---|---|
| ReactiveN (%) | Non-reactiveN (%) | ||
| Female | 98 | 2 (2.0) | 96 (98.0) |
| Male | 103 | 2 (1.9) | 101 (98.1) |
| Total | 201 | 4 (2.0)* | 197 (98.0) |
- Three samples were positive by the Final Comparator.
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Expected Values
A total of 924 prospectively collected specimens from the intended use population were tested with the VITROS Syphilis test. The distribution of the VITROS Syphilis reactive results, observed during the clinical study, is summarized below by age and gender. Due to geographic locations or demographics, assay results obtained in individual laboratories may vary from data presented.
| Age Range(years) | Gender | VITROS Syphilis Results | ||
|---|---|---|---|---|
| ReactiveN (%) | Non-reactiveN (%) | Total | ||
| 18-21 | Female | 2 (5.7) | 33 (94.3) | 35 |
| Male | 5 (25.0) | 15 (75.0) | 20 | |
| 22-29 | Female | 5 (3.6) | 134 (96.4) | 139 |
| Male | 18 (15.7) | 97 (84.3) | 115 | |
| 30-39 | Female | 8 (6.7) | 112 (93.3) | 120 |
| Male | 77 (41.6) | 108 (58.4) | 185 | |
| 40-49 | Female | 5 (11.6) | 38 (88.4) | 43 |
| Male | 31 (50.0) | 31 (50.0) | 62 | |
| 50-59 | Female | 5 (16.7) | 25 (83.3) | 30 |
| Male | 30 (51.7) | 28 (48.3) | 58 | |
| 60-69 | Female | 7 (41.2) | 10 (58.8) | 17 |
| Male | 33 (45.2) | 40 (54.8) | 73 | |
| ≥70 | Female | 0 (0.0) | 4 (100.0) | 4 |
| Male | 9 (39.1) | 14 (60.9) | 23 | |
| Combined | Total | 235 (25.4) | 689 (74.6) | 924 |
Distribution of Reactive and Non-reactive Results Observed in the Clinical Study, by Age and Gender
Conclusion
The conclusions drawn from the nonclinical and clinical studies (discussed above) demonstrate the VITROS Immunodiagnostic Products Syphilis test is substantially equivalent to the cleared predicate device. The information submitted in the premarket notification is complete and supports a substantial equivalence decision.
§ 866.3830
Treponema pallidum treponemal test reagents.(a)
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), theTreponema pallidum immobilization test (T.P.I.), and other treponemal tests used to identify antibodies toTreponema pallidum directly from infecting treponemal organisms in serum. The identification aids in the diagnosis of syphilis caused by bacteria belonging to the genusTreponema and provides epidemiological information on syphilis.(b)
Classification. Class II (performance standards).