(273 days)
The Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System is a non-treponemal flocculation test that can qualitatively determine the presence of reagin antibodies in human serum. It may be used to aid in the diagnosis of syphilis when used in conjunction with supplemental treponemal laboratory tests and other clinical information. This test may also be used to detect non-treponemal antibodies in samples serially diluted to establish titer information. This test is not intended for screening blood or tissue donors.
The Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System in a non-treponemal test for the qualitative determination of reagin antibodies in human serum to aid in the diagnosis of syphilis. This test is also used to detect non-treponemal antibodies in samples serially diluted to establish titer information. The system consists of the Gold Standard Diagnostics RPR test reagents and the Gold Standard Diagnostics AIX1000 Agglutination Analyzer. The AIX1000 Analyzer delivers serum from collection tubes into test wells. After antigen suspension is added, the test wells are then incubated while being shaken. An onboard camera creates a high resolution image. The image is then analyzed by the proprietary software algorithm to produce a result.
Here's an analysis of the acceptance criteria and the studies that prove the device meets these criteria, based on the provided text:
Device Name: Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System
K Number: K150358
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" in a bulleted or numbered list with predefined thresholds for all studies. However, performance expectations are implied by the nature of the tests conducted and the reported agreement percentages. I will interpret the reported performance metrics as demonstrating the device meets an implied acceptance for its intended use, particularly through comparison to a predicate device.
| Study Type / Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| Cross Reactivity | No observed cross-reactivity with common viral, bacterial, and autoimmune conditions. | Viral: Rubella (10), VZV (10), HIV (10), Hepatitis B (16), Hepatitis C (11), EBV (10), HSV Type 1 (10), HSV Type 2 (10), CMV (11), Heterophile antibodies (10) - All 0 Reactive. Bacterial: Toxoplasma gondii (10), Leptospira biflexa (10), Borrelia burgdorferi (10) - All 0 Reactive. Autoimmune: SLE (10), Rheumatoid Arthritis (10), Scleroderma (10), Primary Anti-phospholipid Syndrome (16) - All 0 Reactive. (Numbers in parentheses are 'Number Tested'). |
| Interfering Substances | No effect on performance by specified endogenous substances and prescription drugs. | Hemoglobin (20 g/dL), Bilirubin (unconjugated) (15 mg/dL), Cholesterol (250 mg/dL), Albumin (5 g/dL), Gamma Globulin (60 mg/dL), Glucose (120 mg/dL), Triglyceride (500 mg/dL), Antibiotic (Cephalexin) (337 umol/L), Antibiotic (Tetracycline) (34 umol/L). For all substances, RPR samples remained positive where expected; "None Observed" for interference. |
| Precision (Within-Lab) | High agreement (e.g., >90%) within ± 1 titer for various reactivity levels. | - Non-Reactive Serum: 100% agreement (93.6% - 100% C.I.) - Low RPR Reactivity (1:4): 100% agreement (93.6% - 100% C.I.) - Moderately Reactive (1:16): 100% agreement (93.6% - 100% C.I.) - Reactive (1:64): 97.8% agreement (88.2% - 99.9% C.I.) - Highly Reactive (1:128): 100% agreement (93.6% - 100% C.I.) - Reactive control: 100% agreement (54.9% - 100% C.I.) - Non-reactive control: 100% agreement (54.9% - 100% C.I.) |
| Reproducibility | High agreement (e.g., >90%) within ± 1 titer across operators, instruments, days, and runs. | - Non-Reactive Serum: 100% (Between-Runs, Between-Days, Between-Operators, Between-Instruments) - Low RPR Reactivity (1:4): 100% (all categories) - Moderately Reactive (1:16): 100% (all categories) - Reactive (1:64): 100% (Between-Runs, Between-Operators, Between-Instruments), 97.8% (Between-Days) - Highly Reactive (1:128): 100% (Between-Runs, Between-Days, Between-Instruments), 98.1% (Between-Operators) - Reactive control: 100% (90.5% - 100% C.I.) - Non-reactive control: 100% (90.5% - 100% C.I.) |
| Carry-over | No evidence of carry-over (no false positives in negative samples due to highly reactive samples). | All 480 replicates of the negative samples were reported as non-reactive when highly reactive samples were alternated with non-reactive samples. |
| Clinical Agreement (Prospective Samples vs. Predicate) | High Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) with predicate. | PPA: 95.5% (C.I. 77.2% - 99.9%) NPA: 99.9% (C.I. 99.3% - 100%) |
| Clinical Agreement (Retrospective Samples vs. Predicate) | High PPA and NPA with predicate. | PPA: 97.2% (C.I. 95.5% - 98.4%) NPA: 99.1% (C.I. 98.5% - 99.5%) |
| Special Populations (Pregnant Women vs. Predicate) | High PPA and NPA with predicate. | PPA: 100% (C.I. 90.5% - 100%) NPA: 100% (C.I. 98.8% - 100%) |
| Special Populations (HIV Positive Individuals vs. Predicate) | High PPA and NPA with predicate. | PPA: 100% (C.I. 90.5% - 100%) NPA: 100% (C.I. 98.8% - 100%) |
| Healthy Individuals | Low and expected reactivity in a healthy, no-risk population. | All 100 samples from apparently healthy individuals (not at risk, no syphilis test ordered) were non-reactive. |
| Clinical Stages Correlation | High agreement with clinically diagnosed syphilis cases across various stages. | Primary Treated (13/13 reactive), Primary Untreated (12/12 reactive), Secondary Treated (25/25 reactive), Secondary Untreated (25/25 reactive), Latent Treated (25/25 reactive), Latent Untreated (25/25 reactive). All showed 100% agreement with corresponding 95% C.I. ranges of 77.9%-100% to 88.7%-100%. |
2. Sample Sizes Used for the Test Set and Data Provenance
The document describes several test sets:
- Cross Reactivity: Panels of 10-16 individual patient samples per condition (totaling 17 conditions for viral, bacterial, and autoimmune).
- Interfering Substances: 5 samples (1 non-reactive, 4 reactive) per interfering substance.
- Precision: 5 samples (Non-reactive, Low RPR (1:4), Moderately Reactive (1:16), Reactive (1:64), Highly Reactive (1:128)). Each tested in 9 replicates.
- Reproducibility: The same 5 sample panels as precision, tested across 6 operators, 3 instruments, 2 runs over 5 days.
- Carry-over: 1 reactive (1:64), 1 highly reactive (1:128), and 2 non-reactive samples. Highly reactive samples alternated with non-reactive samples 96 times per run over 5 runs.
- Clinical Studies - Prospectively Collected Samples:
- Sample Size: 765 serum samples.
- Data Provenance: Collected prospectively from patient samples with a physician's order for syphilis testing. Collected at two geographically distinct reference laboratories (Southeastern and Western United States).
- Clinical Studies - Retrospectively Collected Samples:
- Sample Size: 2,246 samples.
- Data Provenance: Collected retrospectively from patients referred for syphilis testing. Obtained from sample brokers who collect from multiple sites across the United States. Collection dates: January 2005 - July 2014.
- Clinical Studies - Pregnant Women (Retrospective):
- Sample Size: 250 non-reactive, 30 reactive (spiked) samples. Total 280.
- Data Provenance: Retrospectively collected from pregnant women at one site (Southeastern United States). Collection dates: July 2012 - August 2013.
- Clinical Studies - HIV Positive Individuals (Retrospective):
- Sample Size: 250 non-reactive, 30 reactive samples. Total 280.
- Data Provenance: Retrospectively collected from HIV positive individuals at four sites (one Southeastern, one Mid-Western States). Collection dates: February 2012 - June 2015.
- Apparently Healthy Individuals (Prospective):
- Sample Size: 100 serum samples.
- Data Provenance: Prospectively collected from healthy individuals not at risk for syphilis and for whom a syphilis test had not been ordered (submitted for routine chemistry testing).
- Correlation with Clinically Diagnosed Syphilis Sera - Various Stages (Purchased Panel):
- Sample Size: Primary Treated (13), Primary Untreated (12), Secondary Treated (25), Secondary Untreated (25), Latent Treated (25), Latent Untreated (25).
- Data Provenance: Purchased from serum brokers, characterized by clinical diagnosis.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not mention the use of human experts to establish ground truth for the test sets in the context of adjudication or interpretation of the RPR results. Instead, it relies on:
- Reference laboratory results (for prospective samples).
- Predicate device results (for comparison in clinical studies).
- FDA-cleared treponemal (TP) assays (for further investigation of discrepant non-treponemal results).
- Clinical diagnosis (for the purchased syphilis stage panel).
- Serum broker confirmation of disease markers (for cross-reactivity samples).
Therefore, there is no direct information on the number or qualifications of experts involved in establishing ground truth through manual interpretation of RPR images or similar tasks for the "AIX1000" aspect. The 'AI' component is described as proprietary software interpreting images (standalone).
4. Adjudication Method for the Test Set
Adjudication methods (like 2+1, 3+1) are typically used when multiple human readers interpret the same image/case and disagreements need to be resolved. This device is an automated test system for a flocculation assay where the "AIX1000 Agglutination Analyzer" uses a proprietary software algorithm to produce a result.
For the discrepancies in the clinical studies where the GSD AIX1000 RPR Test System disagreed with the comparator device:
- Prospective Samples: The two discrepant samples were tested on a "third FDA cleared RPR assay."
- Retrospective Samples: The 31 discrepant samples were tested on a "third FDA cleared RPR assay."
This suggests a form of tie-breaking or external reference testing for discrepant results, rather than a human expert adjudication of visual interpretations by the device itself.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
No, an MRMC comparative effectiveness study was not conducted. The device is an automated test system that interprets RPR assay results without direct human intervention in the interpretation process described. The comparisons were between the automated device and a predicate automated device or clinical outcomes, not between human readers with and without AI assistance.
6. If a Standalone Performance (i.e., algorithm only without human-in-the-loop performance) was Done
Yes, the studies reported represent standalone performance of the Gold Standard Diagnostics AIX1000 RPR Automated Test System. The device's proprietary software algorithm directly produces the results from images captured by its onboard camera. The clinical studies (prospective, retrospective, special populations) directly compare the device's output to a predicate device's output or clinical diagnosis, without human modification or override of the AIX1000's initial determination. The interpretation of the flocculation assay itself is automated.
7. The Type of Ground Truth Used
The ground truth or reference methods varied depending on the study:
- Clinical Studies (Prospective and Retrospective): The primary ground truth for comparison was the legally marketed predicate device (Arlington Scientific Inc. (ASI) RPR Card Test for syphilis on the ASiManager-AT Analyzer). For discrepant samples, a third FDA cleared RPR assay was used as a tie-breaker. Further investigation for NT+ samples used an FDA cleared treponemal (TP) assay.
- Correlation with Clinically Diagnosed Syphilis Sera: Clinical Diagnosis (Primary, Secondary, Latent stages as characterized by documented symptoms, dark field microscopy, and reactive treponemal/non-treponemal tests).
- Cross-Reactivity Study: Confirmation of disease markers by serum brokers.
- Special Populations (Pregnant Women, HIV Positive): Predicate device results, and also confirmed pregnancy status via HCG test and HIV positive status.
- Apparently Healthy Individuals: Lack of risk factors and no physician's order for syphilis testing defined this as "healthy."
8. The Sample Size for the Training Set
The document does not provide information on the sample size used for the training set for the proprietary software algorithm. This information is typically proprietary to the manufacturer and not usually detailed in 510(k) summaries unless specifically requested or deemed critical for substantial equivalence. The focus of the 510(k) is often on comparing the new device's performance to a predicate, rather than the internal development of its algorithm.
9. How the Ground Truth for the Training Set Was Established
Similar to the training set size, the document does not provide information on how the ground truth for the training set was established. Since the device uses a "proprietary software algorithm" to analyze images for flocculation, it can be inferred that this algorithm was developed and trained using a collection of RPR test results with established reactivity and titer values. However, the specifics of this ground truth (e.g., expert consensus on visual flocculation, correlation with other assays) are not detailed in this submission.
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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
Nov 12, 2015
Gold Standard Diagnostics Napoleon Monce Director, Product Development 2851 Spafford Street Davis, CA 95618
Re: K150358
Trade/Device Name: Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System
Regulation Number: 21 CFR 866.3820 Regulation Name: Treponema pallidum nontreponemal test reagents Regulatory Class: II Product Code: GMQ Dated: October 7, 2015 Received: October 9, 2015
Dear Mr. Monce:
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 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.
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If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638 2041 or (301) 796-7100 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" (21 CFR 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 (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours,
Tamara V. Feldblyum -S 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) K150358
Device Name
The Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System
Indications for Use (Describe)
The Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System is a non-treponemal flocculation test that can qualitatively determine the presence of reagin antibodies in human serum. It may be used to aid in the diagnosis of syphilis when used in conjunction with supplemental treponemal laboratory tests and other clinical information. This test may also be used to detect non-treponemal antibodies in samples serially diluted to establish titer information. This test is not intended for screening blood or tissue donors.
Type of Use (Select one or both, as applicable)
| ☑ For Institution Use (21 CFR 601.2) | ☐ For Compassionate Use (21 CFR 601.21) |
|---|---|
| -------------------------------------------------------------------------------------- | ----------------------------------------- |
X Prescription Use (Part 21 CFR 801 Subpart D)
Over-The-Counter Use (21 CFR 801 Subpart C)
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Image /page/3/Picture/0 description: The image is a logo for Gold Standard Diagnostics. The logo is black text with a gold globe in the upper left corner. The text reads "GOLD STANDARD" in large, bold letters, with "DIAGNOSTICS" in smaller letters below. There is a small "SM" symbol in the upper right corner of the logo.
510(k) Summary
This 510(k) summary is being submitted in accordance with the requirement of SMDA 1990 and 21 CFR 807.92.
-
- Submitter's Name: Gold Standard Diagnostics 2851 Spafford St. Davis, CA. 95618 Address: Phone Number: 530-759-8000 Contact Person: Napoleon Monce Date: February 9, 2015
-
- Product and Trade Name: Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System
Common Name: Rapid Plasma Reagin (RPR) Test
Regulation Section: (21 CFR 866.3820) Treponema pallidum non-treponemal test reagents.
Classification: Class II
Product Code: GMQ
3) Legally Marketed Device to Which the Submitter Claims Equivalence:
Arlington Scientific Inc. (ASI) RPR Card Test for syphilis on the ASiManager-AT Analyzer (K111356).
4) Description of the Device:
The Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System in a non-treponemal test for the qualitative determination of reagin antibodies in human serum to aid in the diagnosis of syphilis. This test is also used to detect non-treponemal antibodies in samples serially diluted to establish titer information. The system consists of the Gold Standard Diagnostics RPR test reagents and the Gold Standard Diagnostics AIX1000 Agglutination Analyzer. The AIX1000 Analyzer delivers serum from collection tubes into test wells. After antigen suspension is added, the test wells are then incubated while being shaken. An onboard camera creates a high resolution image. The image is then analyzed by the proprietary software algorithm to produce a result.
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The RPR test reagents consist of a reactive control, a non-reactive control, and the antigen suspended in a carbon solution. When the antigen is mixed with sera, if antibodies are present, they will bind to the antigen and form black flocculants due to the presence of carbon particles. If no antibodies are present, then the carbon particles remain evenly distributed.
The antigen used in the Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System is a modified VDRL carbon antigen. The formulation is the same as that established by the Center for Disease Control (CDC) containing 0.03% cardiolipin, 0.9% cholesterol, and 0.21% lecithin.
The kit also includes untreated, 48 well reaction plates a reactive control and a non-reactive control.
1 Kennedy, E.J. and Creighton, E.T. Venereal Disease Research Laboratory (VDRL) Slide Test. Syphilis Manual, Chapter 8. 1998. http://www.cdc.gov/std/syphilis/manual-1998/CHAPT8.pdf
5) Intended Use of the Device:
The Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System is a non-treponemal flocculation test that can qualitatively determine the presence of reagin antibodies in human serum. It may be used to aid in the diagnosis of syphilis when used in conjunction with supplemental treponemal laboratory tests and other clinical information. This test may also be used to detect non-treponemal antibodies in samples serially diluted to establish titer information. This test is not intended for screening blood or tissue donors.
6) Comparison with the Predicate Device:
The tables below provide a comparison of the Gold Standard Diagnostics (GSD) AIX1000 Rapid Plasma Reagin (RPR) Automated Test System (subject device: K150358) with the Arlington Scientific Inc. (ASI) PRP Card Test for syphilis on the ASiManager-AT Analyzer (predicate device: K111356).
| Similarities | ||
|---|---|---|
| Item | Subject Device: Gold StandardDiagnostics AIX1000 Rapid PlasmaReagin (RPR) Automated TestSystem (K150358) | Predicate Device: ASIRPR Card Test for syphilison the ASiManager-ATAnalyzer (K111356) |
| Intended Use | The Gold Standard Diagnostics AIX1000Rapid Plasma Reagin (RPR) AutomatedTest System is a non-treponemalflocculation test that can qualitativelydetermine the presence of reaginantibodies in human serum. It may beused to aid in the diagnosis of syphiliswhen used in conjunction withsupplemental treponemal laboratory testsand other clinical information. This testmay also be used to detect non- | The ASiManger-AT is intendedto be used as an integrateddigital particle analyzer toobjectively interpret the ASIRPR Card Test for syphilis. TheASiManger-AT is designed toprovide standardized testinterpretation, an initialpredictive titer analysis, andprovides for storage, retrievaland transmittal of the test |
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| treponemal antibodies in samples seriallydiluted to establish titer information. Thistest is not intended for screening blood ortissue donors. | results. It is intended to beacquired, possessed and usedonly by healthcareprofessionals. For in vitroDiagnostic Use Only, notintended for screening bloodand tissue donors. | |
|---|---|---|
| Assay Format | Reports qualitative results and titer ofnon-treponemal antibodies in seriallydiluted samples | Same |
| Technology | Flocculation test | Same |
| Antigen | Modified VDRL carbon antigen | Same |
| Reported Results | Reactive, non-reactive, titer results | Same |
| Interpretation | Automated | Same |
| Differences | |||
|---|---|---|---|
| Item | Subject Device: Gold StandardDiagnostics AIX1000 Rapid PlasmaReagin (RPR) Automated TestSystem (K150358) | Predicate Device: ASI RPRCard Test for syphilis onthe ASiManager-ATAnalyzer (K111356) | |
| SampleProcessing | Automated | Manual | |
| Sample Matrix | Serum | Serum or Plasma | |
| Controls | Reactive and non-reactive | Reactive, weak reactive, non-reactive |
6(b1): Nonclinical Studies:
Cross Reactivity
The study was conducted to evaluate potential cross reactivity from different disease conditions. A panel of antibodies from 17 different conditions (10 viral, 3 bacterial, and 4 autoimmune conditions) was obtained from serum brokers who confirmed the presence of each respective disease marker. The samples were tested on the GSD AIX1000 RPR Automated Test System. Each condition tested 10-16 individual patient samples. Reactive and non-reactive controls were run on each day of testing. The results are summarized below:
| Number | Number | |
|---|---|---|
| Positive For | Tested | Reactive |
| Rubella | 10 | 0 |
| Vericella Zoster Virus (VZV) | 10 | 0 |
| Human Immunodeficiency Virus (HIV) | 10 | 0 |
| Hepatitis B | 16 | 0 |
| Hepatitis C | 11 | O |
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| Epstein Barr Virus (EBV) | 10 | 0 |
|---|---|---|
| Herpes Simplex Virus (HSV) Type 1 | 10 | 0 |
| Herpes Simplex Virus (HSV) Type 2 | 10 | 0 |
| Cytomegalovirus (CMV) | 11 | 0 |
| Heterophile antibodies* | 10 | 0 |
| Toxoplasma gondii | 10 | 0 |
| Leptospira biflexa | 10 | 0 |
| Borrelia burgdorferi | 10 | 0 |
| Systemic Lupus Erythematosus (SLE) | 10 | 0 |
| Rheumatoid Arthritis | 10 | 0 |
| Scleroderma | 10 | 0 |
| Primary Anti-phospholipid Syndrome | 16 | 0 |
"Heterophiles samples were tested for infectious mononucleosis (EBV and un-related non-EBV heterophile antibodies).
Interfering Substances
The effect of potential interfering substances on samples using the GSD AIX1000 RPR Automated The panel consisted of seven endogenous substances and two Test System was evaluated. prescription drugs that could be used to treat syphilis patients. Five samples, one non-reactive and four reactive samples (with a concentration of 1:2, 1:4, 1:16, and 1:64 from four individual patients), were obtained from a serum broker and were tested in the presence (interferents spiked in-house at the concentration described below) or absence of interferents. The qualitative (non-titer) result was recorded for each sample. The concentrations selected were recommended in the Clinical and Laboratory Standards Institute standard document CLSI EP7-A2. Reactive and non-reactive controls were run on each day of testing. For all substances, the RPR samples remained positive, therefore the tested substances did not affect the performance of the GSD AIX1000 RPR Automated Test System.
| Substance | Concentration | Interference |
|---|---|---|
| Hemoglobin | 20 g/dL | None Observed |
| Bilirubin (unconjugated) | 15 mg/dL | None Observed |
| Cholesterol | 250 mg/dL | None Observed |
| Albumin | 5 g/dL | None Observed |
| Gamma Globulin | 60 mg/dL | None Observed |
| Glucose | 120 mg/dL | None Observed |
| Triglyceride | 500 mg/dL | None Observed |
| Antibiotic (Cephalexin) | 337 umol/L | None Observed |
| Antibiotic (Tetracycline) | 34 umol/L | None Observed |
Precision
To test the precision of the GSD AIX1000 RPR Automated Test System, a within-lab precision study This study was conducted in-house with clinical samples at the following was conducted. concentrations: a low RPR reactivity (<1:8), a moderately reactive (1:16), a reactive (1:64), highly reactive (1:128), and a non-reactive serum (the highly reactive sample was a pooled sample, while all the other samples were individual patient sera). Each concentration level was tested in replicates of
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nine. These nine replicates were spread across five panels that were tested every day for five consecutive days by one operator using one instrument. The sample panels were masked and randomized. Reactive and non-reactive controls were run on each day of testing. The results are summarized below.
| SampleReactivity | Non-reactive | Neat | 1:2 | 1:4 | 1:8 | 1:16 | 1:32 | 1:64 | 1:128 | ≥1:256 | % Agreementwithin ± 1 titer(95% C.I.) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Non-ReactiveSerum | 45 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 100%(93.6% - 100%) |
| Low RPRReactivity(1:4) | 0 | 0 | 2 | 38 | 5 | 0 | 0 | 0 | 0 | 0 | 100%(93.6% - 100%) |
| ModeratelyReactive(1:16) | 0 | 0 | 0 | 0 | 27 | 18 | 0 | 0 | 0 | 0 | 100%(93.6% - 100%) |
| Reactive(1:64) | 0 | 0 | 0 | 0 | 0 | 1 | 25 | 15 | 4 | 0 | 97.8%(88.2% - 99.9%) |
| HighlyReactive(1:128) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 19 | 19 | 7 | 100%(93.6% - 100%) |
| Reactivecontrol | 0 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 100%(54.9% - 100%) |
| Non-reactivecontrol | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 100%(54.9% - 100%) |
Reproducibility
To investigate operator-to-operator and instrument variability, six operators, three instruments, and two runs were tested each day over five consecutive days as outlined in the following testing schedule:
| Operator &InstrumentID | Day 1 | Day 2 | Day 3 | Day 4 | Day 5 | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Run 1 | Run 2 | Run 1 | Run 2 | Run 1 | Run 2 | Run 1 | Run 2 | Run 1 | Run 2 | |
| Operator 1,Instrument 1 | PanelI | PanelII | PanelIII | PanelIV | PanelV | |||||
| Operator 2,Instrument 1 | PanelII | PanelIII | PanelIV | PanelV | PanelI |
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| Operator 3,Instrument 2 | Panel III | Panel IV | Panel V | Panel I | Panel II |
|---|---|---|---|---|---|
| Operator 4,Instrument 2 | Panel IV | Panel V | Panel I | Panel II | Panel III |
| Operator 5,Instrument 3 | Panel V | Panel I | Panel II | Panel III | Panel IV |
| Operator 6,Instrument 3 | Panel I | Panel II | Panel III | Panel IV | Panel V |
Each operator tested the five sample panels (described in the Precision section above). The sample panels were masked and randomized. Reactive and non-reactive controls were run on each day of testing. The results are summarized below:
| SampleReactivity | Non-reactive | Neat | 1:2 | 1:4 | 1:8 | 1:16 | 1:32 | 1:64 | 1:128 | >1:256 | % Agreementwithin ± 1 titer(95% C.I.) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Non-ReactiveSerum | રત | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 100%(94.5% - 100%) |
| Low RPRReactivity(1:4) | 0 | 0 | 0 | 23 | 31 | 0 | 0 | 0 | 0 | 0 | 100%(94.5% - 100%) |
| ModeratelyReactive(1:16) | 0 | 0 | 0 | 0 | 7 | 42 | 5 | 0 | 0 | 0 | 100%(94.5% - 100%) |
| Reactive(1:64) | 0 | 0 | 0 | 0 | 0 | 0 | 42 | 12 | 0 | 0 | 100%(94.5% - 100%) |
| HighlyReactive(1:128) | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 28 | 20 | 5 | 98.1%(90.1% - 99.9%) |
| Reactivecontrol | 0 | 30 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 100%(90.5% - 100%) |
| Non-reactivecontrol | 30 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 100%(90.5% - 100%) |
The sample agreement (within ± 1 titer) for between-days, between-oays, between-operators, and between-instruments are summarized below:
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| Sample Reactivity | Between-Runs | Between-Days | Between-Operators | Between-Instruments |
|---|---|---|---|---|
| Non-Reactive Serum | 100% | 100% | 100% | 100% |
| Low RPR Reactivity(1:4) | 100% | 100% | 100% | 100% |
| Moderately Reactive(1:16) | 100% | 100% | 100% | 100% |
| Reactive(1:64) | 100% | 97.8% | 100% | 100% |
| Highly Reactive(1:128) | 100% | 100% | 98.1% | 100% |
Carry-over
The purpose of the carry-over study was to uncover the presence of contamination in negative specimens due to carry-over of RPR antibodies during sample processing on the GSD AIX1000 RPR Automated Test System. The study was conducted over three consecutive days on a single AIX1000 instrument. One reactive (1:64), one highly reactive (1:128) and two negative samples were tested over five runs. The samples used were from individual patients (not pooled). The qualitative (nontiter) result was recorded for each sample. Highly reactive samples were alternated with non-reactive samples (reactive 1 with non-reactive 1; reactive 1 with non-reactive 2- tested twice; reactive 2 with non-reactive 1; and reactive 2 with non-reactive 2) 96 times per run. All 480 replicates of the negative samples were reported as non-reactive, therefore, no evidence of carry-over was observed.
6(b2): Clinical Studies:
i. Prospectively Collected Samples
Prospective sample collection was conducted at two geographically distinct (Southeastern and Western United States) reference laboratories that received samples from local clinics, hospitals, and Testing was conducted at three sites (one in house and two locations that doctor's offices. represented the intended use sited for the GSD AIX1000 RPR Automated Test System. For all testing sites, reactive and non-reactive external controls were tested with the assay on each day of testing. All 765 serum samples were collected prospectively from patient samples with a physician's order to perform syphilis testing. Samples were stored frozen (-20°C) for a maximum of five months before testing. All samples that were shipped, were transported and stored frozen until testing. All three sites performed their own comparator testing.
All prospectively collected samples were "de-identified", therefore, only pregnancy and HIV status was recorded. No information regarding gender, age, syphilis stage, or antibiotic use was available.
Seven hundred sixty five (765) serum samples were tested on both the GSD RPR Automated Test System and on the comparator device (Arlington Scientific Inc. RPR Card Test for syphilis on the
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ASiManager-AT Analyzer). The initial tests resulted in 26 invalid results (invalid rate of 3.4% with 95% CI: 2.33% - 4.93%). All 26 samples were re-tested and gave non-reactive results. The comparison of results for the prospectively collected clinical samples is summarized below:
| Prospective Samples | Comparator Device | |||
|---|---|---|---|---|
| Reactive | Non-reactive | Total | ||
| GSD AIX1000 | Reactive | 21 | 1* | 22 |
| RPR Test System | Non-reactive | 1* | 742 | 743 |
| Total | 22 | 743 | 765 |
The two discrepant samples were tested on a third FDA cleared RPR assay. Both samples were nonreactive on the third RPR assay.
The positive percent agreement and negative percent of the GSD AIX1000 RPR Automated Test System with the comparator device (along with their 95% confidence intervals) are 95.5% (C.I. 77.2% - 99.9%) and 99.9% (C.I. 99.3% - 100%), %), respectively.
To further investigate the serologic status of the non-treponemal antibody positive samples (NT+), the samples that gave a reactive result either by the GSD AIX1000 RPR Automated Test System or by the comparator device were further tested on an FDA cleared treponemal (TP) assay. Of the 21 samples that were non-treponemal antibody reactive on both the GSD AIX1000 RPR Automated Test System and on the comparator device, only 18 (18/21 = 85.7%) had enough volume for further testing; all 18 samples were positive for TP antibodies. The one sample that was NT+ on the GSD AIX1000 Automated Test System and non-treponemal non-reactive (NT-) on the comparator device was negative for TP antibodies. The one sample that was NT- on the GSD AIX1000 Automated Test System and NT+ on the comparator device was negative for TP antibodies. The 742 samples that were concordant non-reactive with the test device and the comparator device did not receive further TP testing (742/765 = 97.0%).
ii. Retrospectively Collected Samples
In addition, 2,246 retrospectively collected samples from patients referred for syphilis testing were tested on the GSD AIX1000 RPR Automated Test System and on the comparator device. The samples were obtained from sample brokers who collect from multiple sites across the United States. The samples were collected between January 2005 and July 2014 and stored at -20°C until the time of testing. Samples included 607 men and 666 women ranging in age from 10 to 98 years (mean = 35 years. The gender and age of the remaining samples were not disclosed). All samples were tested inhouse by a single operator. Reactive and non-reactive controls were tested with the assay on each day of testing. The initial tests resulted with six invalid rate of 0.27% with 95% CI: 0.12% - 0.58%). All six samples were re-tested and gave one reactive and five non-reactive results. The results are summarized below:
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| Retrospective Samples | Comparator Device | |||
|---|---|---|---|---|
| Reactive | Non-reactive | Total | ||
| GSD AIX1000 | Reactive | 556 | 15* | 571 |
| RPR Test System | Non-reactive | 16* | 1659 | 1675 |
| Total | 572 | 1674 | 2246 |
The 31 discrepant samples were tested on a third FDA cleared RPR assay. Of the 16 GSD nonreactive and comparator device reactive samples, the third RPR assay called 12 reactive and 4 nonreactive. Of the 15 GSD AIX1000 RPR Automated Test System reactive and comparator device nonreactive samples, the third RPR assay called 11 reactive and 4 non-reactive.
The positive percent agreement and negative percent of the GSD AIX1000 RPR Automated Test System with the comparator device (along with their 95% confidence intervals) are 97.2% (C.I. 95.5% - 98.4%) and 99.1% (C.I. 98.5% - 99.5%), respectively.
To further investigate the serologic status of the non-treponemal antibody positive samples (NT+), the samples that gave a reactive result either by the GSD AIX1000 RPR Automated Test System or the comparator device were further tested on an FDA cleared treponemal (TP) assay. Of the 556 samples that were non-treponemal antibody reactive on both the GSD AIX1000 RPR Automated Test System and on the comparator device, only 404 had enough volume for further TP (404/556 = 72.7%). Of the 15 samples that were NT+ on the GSD AIX1000 RPR Automated Test System and non-reactive for non-treponemal antibodies (NT-) on the comparator device, only three had enough volume for further TP testing (9/16 = 56.3%). Of the 16 samples that were NT- on the GSD AIX1000 RPR Automated Test System and NT+ on the comparator device, only nine had enough volume for further TP testing. A total of 416 samples that were reactive by either the test device or the comparator device received further TP testing. Samples that were concordant non-reactive with the test device and the comparator device did not receive further TP testing. The results are summarized below:
| ComparatorDevice NT + /Trep + | ComparatorDevice NT + /Trep - | ComparatorDevice NT - /Trep + | ComparatorDevice NT - /Trep - | ||
|---|---|---|---|---|---|
| GSD AIX1000NT Assay Result | Reactive | 366 | 38 | 1 | 2 |
| Non-reactive | 5 | 4 | N/A* | N/A* |
*Samples with concordant non-reactive results by the comparator device and the GSD AIX1000 RPR Automated Test System did not receive further TP testing.
Three hundred thirty (330) of the retrospective collected samples were tested for titer (330/587 samples collected = 56.2%). The frequency distribution of titer results from samples that are RPR reactive on the GSD AIX1000 RPR Automated Test System is shown in the figure below:
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Image /page/12/Figure/0 description: The image is a bar graph showing the distribution of titer results. The x-axis represents the titer values, ranging from 1:1 to ≥ 1:256, while the y-axis represents the number of samples. The graph indicates that the highest number of samples have a titer of 1:2, with approximately 140 samples. The number of samples decreases as the titer increases, with the lowest number of samples having a titer of ≥ 1:256.
Distribution of Titer Results from Samples Designated as RPR Reactive on the GSD AIX1000 RPR Automated Test System.
iii. Retrospectively Collected Samples from Special Populations
Pregnant Women
In addition, 250 samples that were non-reactive for non-treponemal antibodies (NT-) were retrospectively collected from pregnant women at one site (Southeastern United States). The age of these women ranged from 15-44 years old (median = 29 years old) The samples were collected between July 2012 and August 2013 and stored at -20°C until the time of testing. To create nontreponemal antibody reactive (NT+) samples, sera from 30 individual pregnant women were collected and spiked with a pool created by combining highly reactive RPR positive samples.
Sera from 30 pregnant women were obtained and were tested on an FDA cleared Human Chorionic Gonadotropin (HCG) test to confirm the pregnancy status. All sera gave a positive HCG result. The 30 sera were then spiked with a pool of highly reactive (1:128 and 1:64) RPR positive samples. No more than 10% of the volume from the sera of pregnant women was supplanted by spiking. The spiked sera were tested again on the HCG test to confirm a positive result.
These samples were tested on the GSD AIX1000 RPR Automated Test System and on the comparator device. All samples were tested in-house by a single operator. The identity of the samples was masked. Reactive and non-reactive controls were tested with the assay on each day of testing. No invalid results were obtained. The results are summarized below:
| Pregnant Women | Comparator Device | |||
|---|---|---|---|---|
| Reactive | Non-reactive | Total | ||
| GSD AIX1000 RPR | Reactive | 30 | 0 | 30 |
| Test System | Non-reactive | 0 | 250 | 250 |
| Total | 30 | 250 | 280 |
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The positive percent agreement and negative percent of the GSD AIX1000 RPR Automated Test System with the comparator (along with their 95% confidence intervals) are 100% (C.I. 90.5% - 100%) and 100% (C.I. 98.8% - 100%), %), respectively.
HIV Positive Individuals
In addition, 250 samples that were non-reactive for non-treponemal antibodies (NT-) and 30 samples that were reactive for non-treponemal antibodies (NT+) were retrospectively collected from HIV positive individuals at four sites (one Southeastern, one Mid-Western States). The age ranged from 19-60 years old (median = 41 years). Sixteen (16) women and 71 men were included in this group (the age and gender of the other samples were not disclosed). The samples were collected between February 2012 and June 2015 and stored at -20°C until the time of testing.
These samples were tested on the GSD AIX1000 RPR Automated Test System and the comparator device. All samples were tested in-house by a single operator. The identity of the samples was masked and the samples from HIV positive individuals were randomized with samples collected from HIV negative individuals. Reactive and non-reactive controls were tested with the assay on each day of testing. No invalid results were obtained. The results are summarized below:
| HIV Positive | Comparator Device | |||
|---|---|---|---|---|
| Reactive | Non-reactive | Total | ||
| GSD AIX1000 RPRTest System | Reactive | 30 | 0 | 30 |
| Non-reactive | 0 | 250 | 250 | |
| Total | 30 | 250 | 280 |
The positive percent agreement and negative percent of the GSD AIX1000 RPR Automated Test System with the comparator (along with their 95% confidence intervals) are 100% (C.I. 90.5% - 100%) and 100% (C.I. 98.8% - 100%), respectively.
Apparently Healthy Individuals
To determine the percentage of RPR reactivity with the GSD AIX1000 RPR Automated Test System in a population of apparently healthy individuals, 100 serum samples prospectively collected from healthy individuals not at risk for syphilis and for whom a syphilis test had not been ordered (samples were submitted to the source laboratories for routine chemistry testing) were tested with the GSD AIX1000 RPR Automated Test System. All 100 samples were non-reactive with the GSD AIX1000 RPR Automated Test System.
The percentage of RPR reactivity with the GSD AIX1000 RPR Automated Test system in the 765 prospective serum samples collected from two geographically distinct regions of the United States from patients with a physician's order to perform syphilis testing, 2.9% (22/765) were reactive with the GSD AIX1000 RPR Automated Test System.
Correlation with Clinically Diagnosed Syphilis Sera - Various Stages
A sample panel of sera collected from patients clinically positive for syphilis at various stages of the disease were purchased. The sera consisted of treated samples at the primary, secondary, and latent stages of syphilis. The age, gender, and collection dates for the samples were
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not disclosed. The primary syphilis samples given were characterized by documented genital lesion with positive dark field microscopy (if performed) and with reactive treponemal test. The secondary syphilis samples were characterized by documented rash or mucous patches or condyloma lata with reactive treponemal test. And the latent syphilis samples were characterized by having reactive treponemal and non-treponemal test with a non-reactive non-treponemal test for more than a year or for an unknown duration of infection.
The sera were tested on both the GSD AIX1000 RPR Automated Test System and on the comparator device. The sample panel members were masked and the order of testing was randomized. There were no invalid results reported in any of the tests. The results are summarized below:
| GSD AIX1000 RPR Test System andComparator Device Results | ||||
|---|---|---|---|---|
| Clinical Diagnosis | # Reactive* | # Non-reactive* | % Agreement | 95% C.I. |
| Primary Treated | 13 | 0 | 100% | 79.4% - 100% |
| Primary Untreated | 12 | 0 | 100% | 77.9% - 100% |
| Secondary Treated | 25 | 0 | 100% | 88.7% - 100% |
| Secondary Untreated | 25 | 0 | 100% | 88.7% - 100% |
| Latent Treated | 25 | 0 | 100% | 88.7% - 100% |
| Latent Untreated | 25 | 0 | 100% | 88.7% - 100% |
Note: The results of the sample population tested may not be consisted with what has been reported in the literature. It is important to perform follow-up testing on patients suspected of having syphilis.
7 Conclusion:
From the data, we conclude that the Gold Standard Diagnostics AIX1000 Rapid Plasma Reagin (RPR) Automated Test System is substantially equivalent to the predicate device - the Arlington Scientific Inc. (ASI) RPR Card Test for syphilis on the ASiManager-AT Analyzer (K111356).
§ 866.3820
Treponema pallidum nontreponemal test reagents.(a)
Identification. Treponema pallidum nontreponemal test reagents are devices that consist of antigens derived from nontreponemal sources (sources not directly associated with treponemal organisms) and control sera (standardized sera with which test results are compared) used in serological tests to identify reagin, an antibody-like agent, which is produced from the reaction of treponema microorganisms with body tissues. The identification aids in the diagnosis of syphilis caused by microorganisms belonging to the genusTreponema and provides epidemiological information on syphilis.(b)
Classification. Class II (performance standards).