← Product Code [LSR](/submissions/MI/subpart-d%E2%80%94serological-reagents/LSR) · K200025

# Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit (K200025)

_Gold Standard Diagnostics · LSR · Apr 6, 2020 · Microbiology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/LSR/K200025

## Device Facts

- **Applicant:** Gold Standard Diagnostics
- **Product Code:** [LSR](/submissions/MI/subpart-d%E2%80%94serological-reagents/LSR.md)
- **Decision Date:** Apr 6, 2020
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 866.3830
- **Device Class:** Class 2
- **Review Panel:** Microbiology

## Indications for Use

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.

## Device Story

The Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit is an in vitro diagnostic assay used in clinical laboratories. It detects IgG antibodies to B. burgdorferi sensu stricto in human serum. The device uses antigen-coated microtiter plates (B. burgdorferi B31 lysate, 2591 lysate, and recombinant VlsE protein). Patient serum is added to wells; if specific antibodies are present, they bind to the antigens. After washing, a goat anti-human IgG-horseradish peroxidase conjugate is added, followed by a TMB chromogenic substrate. The enzymatic reaction produces a blue color, which turns yellow upon addition of a stop solution. The intensity is measured photometrically at 450nm. Results are interpreted against a cutoff control to determine if the sample is positive, equivocal, or negative. The test serves as a first-tier presumptive screen; positive or equivocal results must be confirmed by a second-tier Western blot assay to support a clinical diagnosis of Lyme disease.

## Clinical Evidence

Clinical performance evaluated via prospective study (n=523) and sensitivity study (n=114). Prospective study showed 90.2% PPA and 99.6% NPA compared to predicate. Sensitivity study across disease stages (early, disseminated, late) showed improved detection over predicate, particularly in early (46.6% vs 27.6%) and disseminated (82.4% vs 52.9%) stages. CDC panel testing confirmed performance across characterized samples. Bench testing included precision, reproducibility, analytical specificity, cross-reactivity, and interference studies.

## Technological Characteristics

ELISA-based immunoassay. Antigens: B. burgdorferi sensu stricto strain B31 lysate, strain 2591 lysate, and recombinant VlsE protein. Detection: Goat anti-human IgG-HRP conjugate with TMB substrate. Readout: Photometric microplate reader at 450nm. Manual procedure.

## Regulatory Identification

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

## Predicate Devices

- Trinity Biotech MarDx Borrelia burgdorferi EIA IgG Test Kit ([K894224](/device/K894224.md))

## Submission Summary (Full Text)

> This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com.
>
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FDA

U.S. FOOD & DRUG

ADMINISTRATION

# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

ASSAY ONLY

## I Background Information:

A 510(k) Number

K200025

B Applicant

Gold Standard Diagnostics

C Proprietary and Established Names

Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit

D Regulatory Information

|  Product Code(s) | Classification | Regulation Section | Panel  |
| --- | --- | --- | --- |
|  LSR | Class II | 21 CFR 866.3830 - Treponema Pallidum
Treponemal Test Reagents | MI - Microbiology  |

## II Submission/Device Overview:

A Purpose for Submission:

To obtain a substantial equivalence determination and FDA clearance for a new device.

B Measurand:

Anti-Borrelia burgdorferi IgG antibodies

C Type of Test:

Manual ELISA

Food and Drug Administration

10903 New Hampshire Avenue

Silver Spring, MD 20993-0002

www.fda.gov

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K200025 - Page 2 of 9

## III Intended Use/Indications for Use:

### A Intended Use(s):
See Indications for Use below.

### B Indication(s) for Use:
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.

### C Special Conditions for Use Statement(s):
Rx - For Prescription Use Only

### D Special Instrument Requirements:
None

## IV Device/System Characteristics:

### A Device Description:
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 antigen-antibody 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 450nm.

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 grown in *E. coli* SURE2 cells.

### B Principle of Operation:
ELISA

## V Substantial Equivalence Information:

### A Predicate Device Name(s):
Mardx Lyme Disease EIA (IgG) Test System

### B Predicate 510(k) Number(s):
K894224

### C Comparison with Predicate(s):

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K200025 - Page 3 of 9
|  Device & Predicate Device(s): | K200025 | K894224  |
| --- | --- | --- |
|  Device Trade Name | Gold Standard Diagnostics
Borrelia burgdorferi
IgG ELISA Test Kit | Trinity Biotech MarDx
Borrelia burgdorferi EIA IgG
Test Kit  |
|  General Device Characteristic Similarities |  |   |
|  Intended Use/Indications for Use | 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. | Trinity Biotech MarDx Borrelia burgdorferi EIA IgG Test System is a qualitative test intended for use in the presumptive detection of human IgG antibodies to Borrelia burgdorferi in human serum. This EIA system should be used to test serum from patients with a history and symptoms of infection with B. burgdorferi. All positive and equivocal specimens should be retested with a highly specific, second-tier test such as Western blot. Positive second-tier results are supportive evidence of infection with B. burgdorferi. The diagnosis of Lyme disease should be made based on history and symptoms (such as erythema migrans), and other laboratory data, in addition to the presence of antibodies to B. burgdorferi. Negative results (either first or second- tier) should not be used to exclude Lyme disease.  |
|  Technology | ELISA | Same  |
|  Sample Matrix | Human serum | Same  |
|  General Device Characteristic Differences |  |   |
|  Antigens | B. burgdorferi B31 strain,
B. burgdorferi 2591 strain,
B. burgdorferi recombinant VlsE protein from B31 strain | B. burgdorferi B31 strain  |

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VI Standards/Guidance Documents Referenced:

VII Performance Characteristics (if/when applicable):

A Analytical Performance:

1. Precision/Reproducibility:

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 members was tested in duplicate, twice per day, for 12 days. The results are summarized in the following table:

Table 1: Precision Study

|  Sample | N | Mean Units |  | Within-Run | Between-Run | Between-Day | Total  |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  Moderate Positive | 48 | 20.3 | SD | 1.488 | 1.312 | 1.257 | 1.439  |
|   |   |   |  CV | 7.3% | 6.5% | 6.2% | 7.1%  |
|  Low Positive | 48 | 11.5 | SD | 0.845 | 0.718 | 0.718 | 0.816  |
|   |   |   |  CV | 7.4% | 6.2% | 6.2% | 7.1%  |
|  High Negative | 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%  |
|  Positive Control | 48 | 17.2 | SD | 0.947 | 0.649 | 0.739 | .932  |
|   |   |   |  CV | 5.5% | 3.8% | 4.3% | 5.4%  |
|  Cutoff Control | 48 | 10.1 | SD | 0.241 | 0.115 | 0.285 | 0.264  |
|   |   |   |  CV | 2.7% | 1.1% | 2.8% | 2.6%  |
|  Negative Control | 48 | 0.4 | SD | 0.052 | 0.424 | 0.144 | 0.051  |
|   |   |   |  CV | 12.9% | 10.6% | 11.0% | 12.7%  |

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:

K200025 - Page 4 of 9

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Table 2: Reproducibility Study

|  Sample | N | Mean Units |  | Within-Run | Between-Run | Between-Day | Between-Site | Total  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  Moderate Positive | 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%  |
|  Low Positive | 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%  |
|  High Negative | 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%  |
|  Positive Control | 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%  |
|  Cutoff Control | 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%  |
|  Negative Control | 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%  |

# 2. Linearity: N/A

# 3. Analytical Specificity/Interference:

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:

Table 3: Analytical Specificity

|   | Number of Samples | Number Positive/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:

Table 4: Cross Reactivity

|  Infection / Diagnosis | Number of Sera 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%)  |

K200025 - Page 5 of 9

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|  Infection / Diagnosis | Number of Sera Tested | # Positive / (%)  |
| --- | --- | --- |
|  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 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. The tested substances did not affect the performance of the Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test.

Table 5: Interfering Substances

|  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  |

4. Assay Reportable Range: N/A
5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods): N/A
6. Detection Limit: N/A
7. Assay Cut-Off:
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)

K200025 - Page 6 of 9

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analysis was performed to evaluate the performance of the assay and confirm that the chosen cutoff provided the best compromise between sensitivity and specificity.

## B Comparison Studies:

### 1. Method 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. 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:

Table 6: Method Comparison

|   | Predicate IgG ELISA |   |   |   |   |
| --- | --- | --- | --- | --- | --- |
|   |   |  Positive | Equivocal* | Negative | Total  |
|  Gold Standard Diagnostics
Borrelia burgdorferi IgG
ELISA 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:

Table 7: Comparison by Second Tier Testing

|   | Tier 1 Positive or Equivocal | IgG Blot Positive | IgG Blot Negative  |
| --- | --- | --- | --- |
|  Predicate IgG ELISA | 61 | 37 | 24  |
|  Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit | 57 | 37 | 20  |
|  Predicate IgG ELISA + Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit | 55 | 37 | 18  |

K200025 - Page 7 of 9

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|  2nd Tier Percent Agreement  |   |   |
| --- | --- | --- |
|  2nd Tier PPA (95% CI) | 100% (92.2% - 100%) | 37/37  |

2. Matrix Comparison: N/A

## C Clinical Studies:

### 1. Clinical Sensitivity:

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:

Table 8: Clinical Sensitivity

|  Disease Stage | n | Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit | Predicate IgG 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 Centers 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 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:

Table 9: CDC Panel Testing

|  Disease Stage | n | Gold Standard Diagnostics Borrelia burgdorferi IgG ELISA Test Kit |   | Predicate IgG ELISA  |   |
| --- | --- | --- | --- | --- | --- |
|   |   |  Positive or Equivocal | Agreement with Clinical Diagnosis | Positive or Equivocal | Agreement with Clinical Diagnosis  |
|  Healthy | 100 | 1 | 99.0% | 1 | 99.0%  |
|  Early Lyme | 60 | 41 | 68.3% | 21 | 35.0%  |
|  Cardiac Lyme | 3 | 2 | 66.7% | 3 | 100%  |
|  Neurological Lyme | 7 | 6 | 85.7% | 3 | 42.9%  |
|  Late | 20 | 20 | 100% | 20 | 100%  |
|  Look-alike Disease | 90 | 11 | 87.8% | 10 | 88.9%  |

K200025 - Page 8 of 9

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2. Clinical Specificity: N/A
3. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable): N/A

D Clinical Cut-Off: N/A

E Expected Values/Reference Range:

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:

Table 10: Expected Values

|  Population | # Samples | Unit Results |   |   | Qualitative Results  |   |
| --- | --- | --- | --- | --- | --- | --- |
|   |   |  Mean | Range | Std. Dev. | # Positive/ Equivocal | % Positive/ Equivocal  |
|  Normal Endemic | 103 | 3.7 | 0.5 – 14.3 | 2.452 | 4 | 3.9%  |
|  Normal Non-Endemic | 105 | 3.9 | 0.6 – 8.9 | 2.002 | 0 | 0.0%  |
|  Prospective Study | 523 | 4.3 | 0.1 – 22.2 | 4.409 | 57 | 10.9%  |
|  Sensitivity Study | 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.

VIII Proposed Labeling:

The labeling supports the finding of substantial equivalence for this device.

IX Conclusion:

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

K200025 - Page 9 of 9

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**Source:** [https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/LSR/K200025](https://fda.innolitics.com/submissions/MI/subpart-d%E2%80%94serological-reagents/LSR/K200025)

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