(91 days)
The Gold Standard Diagnostics Borrelia burgdorferi igG ELISA Test Kit is intended as a qualitative presumptive (first-step) test for the detection of IgM antibodies to B. burgdorferi sensu stricto in human serum from symptomatic patients of infection. Positive and equivocal results must be supplemented by testing with a second-step Western blot assay.
The kit includes 12 x 8 well Antigen Coated strips, Conjugate, Substrate, Stop Solution, Wash Buffer, Diluent, Negative Control, Positive Control, and Cutoff Control. The controls are provided to determine if the assay is functioning properly and to determine the antibody level. The reagents are sufficient for 96 determinations. During the test procedure, antibodies to B. burgdorferi (sensu stricto) if present in the human serum sample will bind to the antigens coated onto the wells forming antigen-antibody complexes. Excess antibodies are removed by washing. A conjugate of goat anti-human IgG antibodies conjugated with horseradish peroxidase is then added, which binds to the antigenantibody complexes. Excess conjugate is removed by washing. This is followed by the addition of a chromogenic substrate, tetramethylbenzidine (TMB). If specific antibodies to the antigen are present in the patients' serum, a blue color will develop. The enzymatic reaction is then stopped with a stopping solution causing the contents of the well to turn yellow. The wells are read photometrically with a microplate reader at 450mm. The antigens used in the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test kit is a combination of B. burgdorferi sensu stricto strain B31 lysate, B. burgdorferi sensu stricto strain 2591 lysate, and a recombinant VlsE protein from B. burgdorferi sensu stricto strain B31. The lysates use spirochetes growing in BSK-H complete medium until mid-exponential phase. The recombinant VlsE protein is produced in E. coli SURE2 cells and purified by affinity chromatography.
The provided document is a 510(k) summary for the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit, a medical device for diagnosing Lyme disease. It describes the device's technical specifications and the nonclinical and clinical studies performed to demonstrate its substantial equivalence to a legally marketed predicate device.
Here's the breakdown of the acceptance criteria and the study that proves the device meets them:
1. A table of acceptance criteria and the reported device performance
The document does not explicitly present acceptance criteria in a formal table with pass/fail thresholds. Instead, it demonstrates the device's performance through various studies and compares it to a predicate device. The implicit acceptance criteria are that the new device performs comparably to the predicate device and demonstrates acceptable precision, specificity, and sensitivity.
Here's a summary of the reported device performance for key metrics:
| Performance Metric | Reported Device Performance (Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit) | Predicate Device Performance (Trinity Biotech MarDx Borrelia burgdorferi EIA IgG Test Kit) | Notes |
|---|---|---|---|
| Comparison with Predicate Device (523 samples) | |||
| Positive Percent Agreement | 90.2% (55/61) with 95% CI (79.8% - 96.3%) | N/A (this is a comparative measure) | This compares the agreement of positive/equivocal results between the subject device and the predicate device. Equivocal samples were counted as positive for this calculation. |
| Negative Percent Agreement | 99.6% (460/462) with 95% CI (98.5% - 99.9%) | N/A (this is a comparative measure) | This compares the agreement of negative results between the subject device and the predicate device. |
| 2nd Tier Testing (IgG Western Blot) | |||
| 2nd Tier PPA | 100% (37/37) with 95% CI (92.2% - 100%) | N/A (this is a comparative measure) | This indicates that all samples positive or equivocal by both the subject device and the predicate device that also tested positive by Western Blot were identified by the subject device. |
| Clinical Sensitivity (114 clinically characterized samples) | |||
| Early Stage | 46.6% (27/58) | 27.6% (16/58) | The subject device showed higher sensitivity in the early stage compared to the predicate. |
| Disseminated Stage | 82.4% (14/17) | 52.9% (9/17) | The subject device showed significantly higher sensitivity in the disseminated stage compared to the predicate. |
| Late Stage | 97.4% (38/39) | 97.4% (38/39) | Sensitivity in the late stage was identical to the predicate device. |
| Analytical Specificity | |||
| Endemic Region (103 samples) | 96.1% | Not explicitly compared/stated for predicate | Determined by testing asymptomatic individuals from endemic regions. 4 out of 103 samples were positive/equivocal. |
| Non-Endemic Region (105 samples) | 100% | Not explicitly compared/stated for predicate | Determined by testing asymptomatic individuals from non-endemic regions. 0 out of 105 samples were positive/equivocal. |
| Cross-Reactivity (377 samples) | Varies by condition (e.g., Rickettsiosis IgG: 24%, Ehrlichiosis IgG: 20%, EBV IgG: 3%, VZV: 6%) | Not explicitly compared/stated for predicate | A detailed table is provided showing specific cross-reactivity rates with various other infections/conditions. The goal is to demonstrate that the device performs acceptably despite potential cross-reactivity. The implicit acceptance would be that the cross-reactivity profile is comparable to or better than the predicate, or at least clinically acceptable for the intended use. |
| Precision | Within-run CV: 2.7% - 14.2%Between-run CV: 1.1% - 10.6%Between-day CV: 2.8% - 11.0%Total CV: 2.6% - 14.8% (for various sample types) | Not explicitly compared/stated for predicate | A detailed table of SD and CV values for negative, high negative, low positive, moderate positive samples, and controls is provided, demonstrating good precision within their ranges. |
| Reproducibility | Within-run CV: 2.4% - 21.1%Between-run CV: 1.9% - 18.7%Between-day CV: 2.3% - 16.4%Between-site CV: 2.2% - 18.8%Total CV: 2.2% - 18.3% (for various sample types) | Not explicitly compared/stated for predicate | A detailed table of SD and CV values across three sites for negative, high negative, low positive, moderate positive samples, and controls, demonstrating good reproducibility. |
2. Sample sizes used for the test set and the data provenance
- Comparison with Predicate Device: 523 serum samples.
- Provenance: Prospective samples submitted for Lyme serology testing. Conducted at three sites (one internal and two external reference laboratories). The specific country of origin is not noted, but given the FDA submission, it's likely primarily US-based or at least includes US data.
- Cutoff Determination: 210 normal sera (105 from an endemic region, 105 from a non-endemic region). An additional 194 samples (114 Lyme disease, 8 negative healthy, 72 negative Lyme disease with other potential cross-reactive diseases).
- Provenance: Retrospective (these seem to be characterized samples). Specific regions/countries not detailed.
- Precision Study: 48 replicates for each of the 6 panel members (negative, high negative, low positive, moderate positive sample, positive control, cutoff control, negative control).
- Provenance: In-house study.
- Reproducibility Study: 90 replicates for each of 4 panel members (moderate positive, low positive, high negative, negative). 30 or 60 replicates for controls (positive, cutoff, negative).
- Provenance: Tested at three different sites.
- Analytical Specificity: 208 asymptomatic individual samples (103 from an endemic region, 105 from a non-endemic region).
- Provenance: Retrospective (asymptomatic individuals). Specific regions/countries not detailed.
- Cross-Reactivity: 377 samples from various infection/disease conditions.
- Provenance: Obtained from serum vendors, confirmed for positivity for respective markers or clinical diagnosis. Retrospective.
- Clinical Sensitivity (Clinically characterized samples): 114 clinically characterized samples (58 early, 17 disseminated, 39 late stages of Lyme disease).
- Provenance: Retrospective (clinically characterized samples).
- CDC Panel: 280 positive and negative specimens from the CDC.
- Provenance: Retrospective. The CDC panel implies a well-characterized, reference sample set.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
This is an ELISA diagnostic kit, not an AI/imaging device. Therefore, the concept of "experts establishing ground truth" in the sense of radiologists reading images is not directly applicable.
For this type of device:
- Ground Truth: The ground truth for the test samples (e.g., "Lyme positive/negative," "specific infection") is established through clinical characterization, confirmed diagnosis, or established reference panels (like the CDC panel), potentially involving a combination of clinical symptoms, other laboratory tests (e.g., Western blot, PCR), and expert clinical judgment.
- The document states that for the cross-reactivity study, samples were obtained from "serum vendors who confirmed their positivity for each respective marker or clinical diagnosis," implying that the ground truth for these samples was based on established laboratory methods or clinical records, not necessarily adjudicated by human experts in a reading study.
- For the "Clinically characterized samples" in the sensitivity study, the ground truth ("early, disseminated, and late stages of Lyme disease") would have been established by clinicians based on the patients' medical history, symptoms, and other diagnostic findings. The number and specific qualifications of these clinicians are not provided in this summary.
4. Adjudication method for the test set
Not applicable in the context of an ELISA kit where pre-characterized biological samples define the "ground truth." The "adjudication" is inherent in the characterization of the biological samples used for testing, often through a combination of clinical presentation and other established laboratory methods (e.g., a two-tiered testing algorithm for Lyme disease).
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
Not applicable. This is an in vitro diagnostic (IVD) kit, not an AI-assisted diagnostic imaging device that involves human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, this entire study is a "standalone" performance evaluation of the ELISA kit. The device itself (the ELISA kit) provides a quantitative and qualitative result (positive, equivocal, negative) based on the optical density reading, without direct human cognitive input shaping that specific result beyond the laboratory technician performing the assay according to instructions. The interpretation of "positive/equivocal/negative" is based on pre-defined cutoffs.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The ground truth for the various studies includes:
- Clinical Diagnosis/Characterization: For the sensitivity study (early, disseminated, late Lyme disease), the ground truth was based on the clinical status of the patients.
- Reference Panels: The CDC panel specimens serve as a well-characterized reference (positive and negative) for Lyme disease.
- Other Laboratory Confirmatory Tests: For the comparison study, all positive and equivocal samples from both the subject and predicate ELISA were tested by an FDA-cleared IgG Western blot assay, which serves as a second-tier confirmatory ground truth for these specific samples.
- Confirmed Positivity/Clinical Diagnosis from Serum Vendors: For cross-reactivity studies, samples were sourced with confirmed positivity for specific markers or clinical diagnoses.
- Healthy/Asymptomatic Status: For cutoff determination and analytical specificity, ground truth was derived from healthy, asymptomatic individuals from endemic and non-endemic regions.
8. The sample size for the training set
This document describes a premarket notification for a traditional ELISA diagnostic kit, not a machine learning/AI algorithm. Therefore, there is no explicit "training set" in the context of supervised machine learning. The term "training set" is usually associated with AI model development.
For an ELISA kit, development involves:
- Assay Design/Optimization: This is an iterative process using various internal samples to optimize antigen/antibody concentrations, incubation times, buffer compositions, etc.
- Cutoff Determination: As stated, 210 normal sera and 194 other characterized samples were used to determine and confirm the assay cutoff. This set functions somewhat like a "calibration" or "training" set for defining the interpretation thresholds.
9. How the ground truth for the training set was established
Again, this is not a machine learning model. For the samples used in cutoff determination (which is analogous to a "training" or "calibration" phase), the ground truth was established by:
- Normal Sera: Defined as "normal" based on clinical health and potentially geographic origin (endemic/non-endemic for Lyme disease).
- Lyme Disease Samples: "114 samples from different phases of Lyme disease" implies these were clinically characterized Lyme patient samples.
- Other Disease Samples: "72 negative Lyme disease samples but do have other diseases that may cause serologic cross-reactivity," implying a clinical diagnosis of the other disease and a confirmed negative status for Lyme.
The goal of this "cutoff determination" phase is to establish a threshold that optimizes sensitivity and specificity against a diverse set of known samples.
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April 21, 2020
Gold Standard Diagnostics Napoleon Monce Director, Product Development 2851 Spafford St. Davis, California 95618
Re: K200025
Trade/Device Name: Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit Regulation Number: 21 CFR 866.3830 Regulation Name: Treponema Pallidum Treponemal Test Reagents Regulatory Class: Class II Product Code: LSR Dated: December 27, 2019 Received: January 6, 2020
Dear Napoleon 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. 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 located at https://www.accessdata.fda.gov/scripts/cdrh/ofdocs/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.
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
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- for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-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 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
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 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,
Steven R. Gitterman -S
Steven Gitterman, M.D. Ph.D. Deputy Director Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics and Radiological Health Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K200025
Device Name
Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit
Indications for Use (Describe)
The Gold Standard Diagnostics Borrelia burgdorfer igG ELISA Test Kit is intended as a qualitative presumptive (first-step) test for the detection of IgM antibodies to B. burgdorferi sensu stricto in human serum from symptomatic patients of infection. Positive and equivocal results must be supplemented by testing with a second-step Western blot assay.
| 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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Image /page/3/Picture/0 description: The image shows the logo for Gold Standard Diagnostics. The logo features the words "GOLD STANDARD" in large, bold, black letters. To the left of the words is a gold circle with the letters "GSD" inside. Below the words "GOLD STANDARD" is the word "DIAGNOSTICS" in smaller, black letters.
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 Address: 2851 Spafford St. Davis, CA. 95618 Phone Number: 530-759-8000 Contact Person: Napoleon Monce Date: December 27, 2019
-
- Product and Trade Name: Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit
Common Name: Lyme ELISA Test
Regulation Section: 21 CFR 866.3830; Treponema pallidum treponemal test reagents.
Classification: Class II
Product Code: LSR; Reagent, Borrelia Serological Reagent
-
- Legally Marketed Device to Which the Submitter Claims Equivalence: Trinity Biotech MarDx Borrelia burgdorferi EIA IgG Test Kit (K894224).
4) Description of the Device:
The kit includes 12 x 8 well Antigen Coated strips, Conjugate, Substrate, Stop Solution, Wash Buffer, Diluent, Negative Control, Positive Control, and Cutoff Control. The controls are provided to determine if the assay is functioning properly and to determine the antibody level. The reagents are sufficient for 96 determinations.
During the test procedure, antibodies to B. burgdorferi (sensu stricto) if present in the human serum sample will bind to the antigens coated onto the wells forming antigen-antibody complexes. Excess antibodies are removed by washing. A conjugate of goat anti-human IgG antibodies conjugated with horseradish peroxidase is then added, which binds to the antigenantibody complexes. Excess conjugate is removed by washing. This is followed by the addition of a chromogenic substrate, tetramethylbenzidine (TMB). If specific antibodies to the antigen are present in the patients' serum, a blue color will develop. The enzymatic reaction is then stopped with a stopping solution causing the contents of the well to turn yellow. The wells are read photometrically with a microplate reader at 450mm.
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The antigens used in the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test kit is a combination of B. burgdorferi sensu stricto strain B31 lysate, B. burgdorferi sensu stricto strain 2591 lysate, and a recombinant VlsE protein from B. burgdorferi sensu stricto strain B31. The lysates use spirochetes growing in BSK-H complete medium until mid-exponential phase. The recombinant VlsE protein is produced in E. coli SURE2 cells and purified by affinity chromatography.
5) Intended Use of the Device:
The Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test kit is intended as a qualitative presumptive (first step) test for the detection of IgG antibodies to B. burgdorferi sensu stricto in human serum from symptomatic patients or people suspected of infection. Positive and equivocal results must be supplemented by testing with a second-step Western blot assay.
6) Comparison with the Predicate Device:
The tables below provide a comparison of the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test kit with the Trinity Biotech MarDx Borrelia burgdorferi EIA IgG Test kit (predicate device: K894224).
| Similarities | ||
|---|---|---|
| Item | Subject Device: Gold StandardDiagnostics Borrelia burgdorferiIgG ELISA Test Kit | Predicate Device: Trinity BiotechMarDx Borrelia burgdorferi EIA IgGTest Kit |
| Intended Use | The Gold Standard DiagnosticsBorrelia burgdorferi IgG ELISATest kit is intended as a qualitativepresumptive (first step) test for thedetection of IgG antibodies to B.burgdorferi sensu stricto in humanserum from symptomaticpatients or people suspected ofinfection. Positive and equivocalresults must be supplemented bytesting with a second-step Westernblot assay. | Trinity Biotech MarDx Borreliaburgdorferi EIA IgG Test System is aqualitative test intended for use in thepresumptive detection of human IgGantibodies to Borrelia burgdorferi inhuman serum. This EIA system shouldbe used to test serum from patients witha history and symptoms of infection withB. burgdorferi. All positive andequivocal specimens should be retestedwith a highly specific, second-tier testsuch as Western blot. Positive second-tier results are supportive evidence ofinfection with B. burgdorferi. Thediagnosis of Lyme disease should bemade based on history and symptoms(such as erythema migrans), and otherlaboratory data, in addition to thepresence of antibodies to B. burgdorferi.Negative results (either first or second-tier) should not be used to exclude Lymedisease. |
| Assay Format | Antigen coated microtiter plate –96 wells. | Same |
| Technology | ELISA | Same |
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| Sample Matrix | Human serum | Same |
|---|---|---|
| Sample Processing | Dilute Samples 1:100 in Diluent | Same |
| Controls Provided | Positive, Cutoff, Negative | Same |
| Reagents Provided | Diluent, Wash, Conjugate, | Same |
| Reagents Provided | Substrate, Stop Solution | Same |
| Reported Results | Positive, Equivocal, Negative | Same |
| Assay Output | Optical density readings from | Same |
| Assay Output | Spectrophotometer | Same |
| Differences | ||
|---|---|---|
| Item | Subject Device: Gold StandardDiagnostics Borrelia burgdorferiIgG ELISA Test Kit | Predicate Device: Trinity BiotechMarDx Borrelia burgdorferi EIAIgG Test Kit |
| Volumes | 100ul sample, 50ul substrate, 50ul stop solution | 100ul sample, 100ul substrate, 100ul stop solution |
| Incubation | 15/15/15 minutes at roomtemperature | 30/30/10 minutes at roomtemperature |
| Antigens | B. burgdorferi B31 strain,B. burgdorferi 2591 strain,B. burgdorferi recombinant VlsE strain | B. burgdorferi B31 strain |
| Results Interpretation | Convert to units.Negative <9Equivocal 9.0-11.0Positive >11.0 | Convert to units.Negative <0.80Equivocal 0.80-1.19Positive ≥1.2 |
6(b1): Nonclinical Studies:
Determination of the Assay Cutoff
The cutoff was determined by testing a total of 210 normal sera which consisted of 105 sera from an endemic region of Lyme disease and 105 sera from a non-endemic region of Lyme disease. The mean plus two standard deviations was used to determine the assay cutoff. A known positive sample was then diluted to produce a ready to use cutoff control. An additional 194 samples consisting of 114 samples from different phases of Lyme disease, 8 negative healthy samples, 72 negative Lyme disease samples but do have other diseases that may cause serologic cross-reactivity, were tested. A receiver operating characteristics (ROC) analysis was performed to evaluate the performance of the assay and confirm that the chosen cutoff provided the best compromise between sensitivity and specificity.
Precision
To determine the precision of the Borrelia burgdorferi IgG ELISA Test, a within-lab precision study was conducted. A precision panel consisting of a negative sample, a high negative sample, a low positive sample, and a moderate positive sample, along with the kit controls, was tested in-house. The sample panel was masked and randomized. Each of the panel
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| Sample | N | MeanUnits | Within-Run | Between-Run | Between-Day | Total | |
|---|---|---|---|---|---|---|---|
| ModeratePositive | 48 | 20.3 | SD | 1.488 | 1.312 | 1.257 | 1.439 |
| CV | 7.3% | 6.5% | 6.2% | 7.1% | |||
| LowPositive | 48 | 11.5 | SD | 0.845 | 0.718 | 0.718 | 0.816 |
| CV | 7.4% | 6.2% | 6.2% | 7.1% | |||
| HighNegative | 48 | 8.3 | SD | 0.880 | 0.646 | 0.615 | 0.857 |
| CV | 10.6% | 7.8% | 7.4% | 10.4% | |||
| Negative | 48 | 0.8 | SD | 0.116 | 0.049 | 0.076 | 0.113 |
| CV | 14.2% | 6.5% | 10.0% | 14.8% | |||
| PositiveControl | 48 | 17.2 | SD | 0.947 | 0.649 | 0.739 | 0.932 |
| CV | 5.5% | 3.8% | 4.3% | 5.4% | |||
| CutoffControl | 48 | 10.1 | SD | 0.241 | 0.115 | 0.285 | 0.264 |
| CV | 2.7% | 1.1% | 2.8% | 2.6% | |||
| NegativeControl | 48 | 0.4 | SD | 0.052 | 0.424 | 0.144 | 0.051 |
| CV | 12.9% | 10.6% | 11.0% | 12.7% |
members was tested in duplicate, twice per day, for 12 days. The results are summarized in the following table:
Reproducibility
A reproducibility panel consisting of a negative sample, a high negative sample, a low positive sample, and a moderate positive sample, along with the kit controls, was tested at three different sites. The sample panel was masked and randomized. Each of the panel members was tested in triplicate, twice per day, for five days. The Within-Run, Between-Run, Between-Days, and Between-Sites Standard Deviation and Coefficients of Variation (CV) were calculated. The sample panel was masked and randomized. The results are summarized in the following table:
| Sample | N | MeanUnits | Within-Run | Between-Run | Between-Day | Between-Site | Total | |
|---|---|---|---|---|---|---|---|---|
| ModeratePositive | 90 | 21.0 | SD | 1.54 | 0.40 | 1.07 | 0.91 | 1.29 |
| CV | 7.3% | 1.9% | 5.1% | 4.3% | 6.1% | |||
| LowPositive | 90 | 13.7 | SD | 0.72 | 0.34 | 1.09 | 1.24 | 1.28 |
| CV | 5.5% | 2.6% | 8.0% | 9.1% | 9.3% | |||
| HighNegative | 90 | 6.6 | SD | 0.76 | 0.27 | 0.46 | 0.68 | 0.67 |
| CV | 11.7% | 4.1% | 7.0% | 10.3% | 10.2% | |||
| Negative | 90 | 3.0 | SD | 0.33 | 0.56 | 0.49 | 0.56 | 0.55 |
| CV | 21.1% | 18.7% | 16.4% | 18.8% | 18.3% | |||
| PositiveControl | 30 | 19.1 | SD | 0.65 | 0.67 | 0.67 | 0.63 | 0.62 |
| CV | 3.5% | 3.5% | 3.5% | 3.3% | 3.2% |
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| CutoffControl | 60 | 10.0 | SD | 0.25 | 0.22 | 0.23 | 0.22 | 0.22 |
|---|---|---|---|---|---|---|---|---|
| CV | 2.4% | 2.2% | 2.3% | 2.2% | 2.2% | |||
| NegativeControl | 30 | 0.5 | SD | 0.08 | 0.06 | 0.06 | 0.50 | 0.50 |
| CV | 11.0% | 11.0% | 11.0% | 9.5% | 9.6% |
Analytical Specificity
The analytical specificity was determined by testing 208 asymptomatic individuals' samples from endemic and non-endemic regions. The Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test results are summarized in the following table:
| Number of Samples | NumberPositive/Equivocal | Analytical Specificity | |
|---|---|---|---|
| Endemic Region | 103 | 4 | 96.1% |
| Non-endemic Region | 105 | 0 | 100% |
Cross Reactivity
A study using 377 samples was conducted to evaluate potential cross reactivity from different infections and disease conditions. The samples were obtained from serum vendors who confirmed their positivity for each respective marker or clinical diagnosis. The samples were tested on the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test. The results are summarized in the following table:
| Infection / Diagnosis | Number ofSera Tested | # Positive / (%) |
|---|---|---|
| Tick-borne Relapsing Fever IgG | 21 | 0 / (0%) |
| Treponemal Infections (TPPA) | 23 | 0 / (0%) |
| Rickettsiosis IgG | 25 | 6 / (24%) |
| Ehrlichiosis IgG | 10 | 2 / (20%) |
| Babesiosis IgG | 12 | 0 / (0%) |
| H. pylori IgG | 11 | 0 / (0%) |
| Parvovirus B19 IgG | 12 | 0 / (0%) |
| Influenza A&B IgG | 12 | 0 / (0%) |
| Epstein-Barr Virus IgG | 34 | 1 / (3%) |
| Cytomegalovirus IgG | 31 | 0 / (0%) |
| Herpes Simplex Virus IgG | 21 | 0 / (0%) |
| Varicella Zoster Virus | 16 | 1 / (6%) |
| Fibromyalgia | 32 | 0 / (0%) |
| Rheumatoid Arthritis | 12 | 0 / (0%) |
| Autoimmune Disease | 59 | 0 / (0%) |
| Multiple Sclerosis | 23 | 0 / (0%) |
| Severe Periodontitis | 23 | 0 / (0%) |
Interfering Substances
The effect of potential interfering substances on samples using the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test was evaluated. Three samples, a high negative, an equivocal and a low positive were spiked with high levels of interferants and were tested along
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with serum without spiked interferants. The recommended concentrations from the guideline "Interference Testing in Clinical Chemistry" EP07-A3 from the Clinical and Laboratory Standards Institute were used (see table below). The tested substances did not affect the performance of the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test.
| Substance | Concentration | Interference |
|---|---|---|
| Albumin | 60 mg/ml | None detected |
| Bilirubin | 0.4 mg/ml | None detected |
| Cholesterol | 4.0 mg/ml | None detected |
| Hemoglobin | 10 mg/ml | None detected |
| Triglycerides | 15 mg/ml | None detected |
6(b2): Clinical Studies:
Comparison with Predicate Device
Comparison studies were conducted at three sites (one internal and two external reference laboratories) using prospective samples submitted for Lyme serology testing. Five hundred twenty three (523) serum samples were tested on both the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test and on the predicate B. burgdorferi IgG ELISA Test. The results are summarized in the following table:
| Predicate IgG ELISA | |||||
|---|---|---|---|---|---|
| Positive | Equivocal* | Negative | Total | ||
| Gold Standard DiagnosticsBorrelia burgdorferi IgGELISA Test Kit | Positive | 40 | 5 | 2 | 47 |
| Equivocal* | 3 | 7 | 0 | 10 | |
| Negative | 2 | 4 | 460 | 466 | |
| Total | 45 | 16 | 462 | 523 |
*Equivocal samples counted as positive
| Positive percent agreement = 90.2% (55/61) | 95% CI (79.8% - 96.3%) |
|---|---|
| Negative percent agreement = 99.6% (460/462) | 95% CI (98.5% - 99.9%) |
Second Tier Testing: All positive and equivocal samples by the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test and by the Predicate IgG ELISA were tested by an FDA cleared IgG Western blot assay. The results are summarized in the following table:
| Tier 1 Positiveor Equivocal | IgG BlotPositive | IgG BlotNegative | |
|---|---|---|---|
| Predicate IgG ELISA | 61 | 37 | 24 |
| Gold StandardDiagnostics Borreliaburgdorferi IgGELISA Test Kit | 57 | 37 | 20 |
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| Predicate IgG ELISA+Gold Standard Diagnostics Borreliaburgdorferi IgGELISA Test Kit | 55 | 37 | 18 |
|---|---|---|---|
| ----------------------------------------------------------------------------------------------------------------- | ---- | ---- | ---- |
| 2nd Tier Percent Agreement | ||
|---|---|---|
| 2nd Tier PPA(95% CI) | 100%(92.2% - 100%) | 37/37 |
Clinical Sensitivity
Sensitivity Study
A sensitivity study was performed on 114 clinically characterized samples. The samples encompass early, disseminated, and late stages of Lyme disease. The samples were tested on both the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test and on the predicate B. burgdorferi IgG ELISA Test. The results are summarized in the following table:
| DiseaseStage | n | Gold StandardDiagnostics Borreliaburgdorferi IgG ELISATest Kit | PredicateIgG ELISA |
|---|---|---|---|
| Early | 58 | 46.6% (27/58) | 27.6% (16/58) |
| Disseminated | 17 | 82.4% (14/17) | 52.9% (9/17) |
| Late | 39 | 97.4% (38/39) | 97.4% (38/39) |
CDC Panel
A panel of 280 positive and negative specimens from the Center of Disease Control (CDC) for Lyme disease detection was tested on both the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test and on the predicate device. The results are presented as a means to convey further information on the performance of the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test with a masked characterized serum panel. This does not imply an endorsement of the assay by the CDC. The results are summarized in the following table:
| Disease Stage | n | Gold Standard DiagnosticsBorrelia burgdorferi IgGELISA Test Kit | PredicateIgG ELISA | ||
|---|---|---|---|---|---|
| PositiveorEquivocal | % Agreementwith ClinicalDiagnosis | PositiveorEquivocal | % Agreementwith ClinicalDiagnosis | ||
| Healthy | 100 | 1 | 99.0% | 1 | 99.0% |
| Early Lyme | 60 | 41 | 68.3% | 21 | 35.0% |
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| Cardiac Lyme | 3 | 2 | 66.7% | 3 | 100% |
|---|---|---|---|---|---|
| Neurological Lyme | 7 | 6 | 85.7% | 3 | 42.9% |
| Late | 20 | 20 | 100% | 20 | 100% |
| Look-alikeDisease | 90 | 11 | 87.8% | 10 | 88.9% |
Expected Values
The range of values and positivity rate among different studies and population for the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test are as follows:
| Population | # Samples | Unit Results | Qualitative Results | |||
|---|---|---|---|---|---|---|
| Mean | Range | Std.Dev. | #Positive/Equivocal | %Positive/Equivocal | ||
| NormalEndemic | 103 | 3.7 | 0.5 – 14.3 | 2.452 | 4 | 3.9% |
| NormalNon-Endemic | 105 | 3.9 | 0.6 – 8.9 | 2.002 | 0 | 0.0% |
| ProspectiveStudy | 523 | 4.3 | 0.1 – 22.2 | 4.409 | 57 | 10.9% |
| SensitivityStudy | 114 | 13.6 | 0.9 – 40.4 | 7.994 | 81 | 71.1 % |
Note: It is recommended that each laboratory determine its own normal range based on the population.
7) Conclusion:
From the comparison data, we conclude that the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test is substantially equivalent to the Trinity Biotech MarDx Borrelia burgdorferi EIA IgG Test kit (predicate device: K894224).
§ 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).