The Cambridge Biotech Human Lyme B. burgdorferi IgG Western Blot is intended for use in testing human serum samples which have demonstrated positive or equivocal responses using EIA or IFA test procedures to provide supportive evidence of infection with Borrelia burgdorferi.

The Cambridge Biotech Human Lyme B. burgdorferi IgG Western Blot can be used at any time following onset of symptoms. It should also be used for follow up when (1) only IgM antibodies were originally detected, (2) lgG antibodies were detected but were not considered significant, or (3) previously tested seronegative individuals are shown to develop antibodies by EIA or IFA test procedures.

The assay is not intended for use as a screening assay, nor should it be used for analysis of serum from patients who have not demonstrated symptoms of Lyme Disease.

Device Description

The device is a Western Blot assay. Proteins and other antigenic components of the Borrelia spirochete are fractionated by Polyacrylamide Gel Electrophoresis in the presence of Sodium Dodecylsulfate. The separated proteins are electrophoretically transferred from the gel to nitrocellulose membranes, which are subsequently blocked to minimize non-specific binding and cut into strips. These nitrocellulose strips with Borrelia burgdorferi antigens are then reacted with diluted serum and controls (positive and negative sera of defined reactivity) during an incubation period.

During the incubation period, human antibodies specific to the B. burgdorferi antigens, if present in the sample or control, will bind to the antigen to which they have affinity. Unbound serum and non-specific antibodies are washed from the strip. Detection of bound IgG antibodies is accomplished by reacting and incubating the strips with a solution anti-human IgG antibodies conjugated with alkaline containing phosphatase. Unbound conjugate antibodies are removed by washing. The qualitative assessment of the detected IgG antibodies is then accomplished by the reaction of the alkaline phosphatase with a chemical substrate, which is cleaved into a colored, insoluble product that can be visualized. The determination of the reactivity of each unknown specimen is accomplished by comparison of the identified, visualized bands to the Band Identifying and Band Intensity Controls.

AI/ML Overview

This document describes the Cambridge Biotech Human Lyme Borrelia burgdorferi IgG Western Blot kit. Here's an analysis of its acceptance criteria and the study that proves it meets those criteria:

Acceptance Criteria and Reported Device Performance

Criterion	Acceptance Criteria (Implicit)	Reported Device Performance
Specificity	High percentage agreement for negative controls and non-Lyme disease samples.	100% (95% CI: 99.8%-100.0%) from 1062 total normal donor and disease specimens.
Sensitivity (Overall)	Adequate detection of Lyme disease in well-characterized samples, particularly in later stages.	Varies by disease presentation and draw time. Overall from 287 specimens: - Before Treatment (<1 month): 21% - After Treatment (<1 month): 19% - Lyme Late (2-12 months): 88%
Precision	Consistent results across multiple replicates and sites for controls.	100% agreement for disposition of six IgG Controls across three sites. 92% agreement for presentation of diagnostic band.
Reproducibility	High agreement across different sites and comparison to expected results for a reference panel.	100% agreement for IgG disposition scores for 20 specimens across four sites. 87.5% of diagnostic bands scored identically. 94% overall agreement with expected IgG band scores.
Threshold Determination	Ability to differentiate weakly reactive positive samples from highly reactive negative samples.	Demonstrated in preclinical testing comparing intensities of 5 weakly reactive Lyme antibody-positive samples to 5 highly reactive Lyme antibody-negative samples.

Note on Acceptance Criteria: The document implicitly defines acceptance criteria through the presented performance metrics. Explicit pre-defined thresholds for acceptance (e.g., "Sensitivity must be >X%") are not directly stated but are inferred from the reported results being deemed acceptable for 510(k) clearance.

Study Information

2. Sample Size Used for the Test Set and Data Provenance:

Specificity Test Set: 1062 samples. These included "normal donor (from endemic and non-endemic regions) and disease specimens." The specific types of disease specimens (other than Lyme) are not detailed, but they are implied to be non-Lyme conditions to assess specificity.
Sensitivity Test Set: 287 "characterized Lyme disease specimens." These specimens were collected at different times after disease onset. The specimens were from 169 individual patients, with second draws on 92 and third draws on 36.
Precision Test Set: Six IgG Controls, tested in duplicate on each of three days at three test sites (18 replicates per control).
Reproducibility Test Set: 10 positive and negative specimens from the CDC 47-member panel (total 20 specimens, likely 10 positive, 10 negative, or 10 unique, tested for both).
Data Provenance: The document states that "Each of the clinical trial sites provided specimens that were well-characterized by the site." There is no explicit mention of the country of origin, but the "CDC 47-member panel" suggests U.S. data. The studies appear to be prospective for some data collection (e.g., "draw time from disease onset") and retrospective for the use of "archived Lyme Disease specimens" and the CDC panel.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:

Number of Experts: Not explicitly stated.
Qualifications of Experts: Not explicitly stated. However, ground truth was established by "clinical diagnosis of Lyme Disease based on the probability of exposure/infection (tick bite and/or patient presence in potential tick habitats in an endemic region within 30 days prior to the onset of EM), Borrelia isolation by culture (where possible), or, for non-EM patients, the presentation of Late Lyme clinical manifestations (e.g., cardiac, joint-involvement, or neurological symptoms)." Additionally, "Each of the clinical trial sites provided specimens that were well-characterized by the site using Lyme-specific serological analyses, including EIA and Western Blot testing." This implies clinical specialists and laboratory experts were involved in establishing the ground truth.

4. Adjudication Method for the Test Set:

Adjudication Method: Not explicitly described. The reliance on "clinical diagnosis" and "well-characterized by the site" suggests that the site's standard diagnostic procedures, likely involving consensus among clinicians or adherence to established guidelines, served as the adjudication.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done:

No, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not done. This device is a diagnostic kit (Western Blot assay) for detecting antibodies, not an AI-powered image analysis or diagnostic aid that would assist human readers in interpreting complex data.

6. If a Standalone Study (i.e., algorithm only without human-in-the-loop performance) Was Done:

Yes, this was a standalone study. The performance characteristics of the Western Blot kit were evaluated directly, without human interpretation being the primary variable. The "reading" of the bands is part of the test procedure itself, and while human interpretation is involved, the study assesses the kit's ability to produce those bands accurately and reproducibly. The "scoring" of bands in the reproducibility study is an assessment of consistency of interpretation, rather than human performance with or without AI assistance.

7. The Type of Ground Truth Used:

Combined Clinical, Laboratory, and Outcome Data:
- Clinical Diagnosis: Based on exposure, EM presentation, or Late Lyme clinical manifestations (cardiac, joint, neurological symptoms).
- Microbiological Evidence: Borrelia isolation by culture (where possible).
- Laboratory Serology: Lyme-specific serological analyses (EIA and Western Blot testing) at the clinical trial sites.
- Reference Panels: Centers for Disease Control Lyme Disease Serum Panel.
- Outcomes Data: Implied by "After Treatment" and categorization of "Lyme Late" presentations, suggesting assessment based on disease progression and response to treatment.

8. The Sample Size for the Training Set:

The document describes performance evaluation (test sets) rather than a distinct "training set" for an algorithm. This is a traditional diagnostic assay, not a machine learning algorithm. Therefore, the concept of a separate training set as understood in AI/ML is not directly applicable. The "characterized samples used for the establishment of Substantial Equivalence" and the "well-characterized, archived Lyme Disease specimens" served as the basis for demonstrating performance, which is analogous to a validation set in traditional diagnostic development.

9. How the Ground Truth for the Training Set Was Established:

As noted above, there isn't a "training set" in the AI/ML sense. The ground truth for the specimens used to establish performance (analogous to a validation set) was established through:
- Clinical Diagnosis: As detailed in point 7, based on patient history, symptoms, and clinical presentation.
- Borrelia Isolation by Culture: Direct microbiological confirmation where feasible.
- Lyme-specific Serological Analyses by Clinical Sites: EIA and Western Blot testing performed by the trial sites as part of their standard diagnostic procedures.
- Reference Panel Consensus: The CDC Lyme Disease Serum Panel specimens likely have established ground truth based on extensive characterization.

Summary

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KP111169

Section 12 510(k) SUMMARY

Submitted By:

Cambridge Biotech Corporation 1500 East Gude Drive Rockville, Maryland 20850-5307 (301) 251-0800, extension 145 (301) 762-1327 (fax)

Contact Person:

Rebecca Leaper, Vice President - Operations, Responsible Head (301) 251-0800, extension 105

Date of Preparation:

Revised on 4 February, 1998 27 March 1997

Product Name and Information

Name and Address of Owner/Operator, and Manufacturer 1.

Owner/Operator:

Cambridge Biotech Corporation A Wholly Owned Subsidiary of bioMérieux Vitek, Inc. 1500 East Gude Drive Rockville, MD 20850-5307

Manufacturer:

Cambridge Biotech Corporation A Wholly Owned Subsidiary of bioMérieux Vitek, Inc. 1500 East Gude Drive Rockville, MD 20850-5307

FEB | 7 |998

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2. Product Name

Trade Name:	Cambridge Biotech Human Lyme Borreliaburgdorferi IgG Western Blot kit
Common Name:	Lyme IgG Western Blot kit
Classification Name:	Reagent, Borrelia Serological Reagent

3. Claim of Substantial Equivalence

The characterized samples used for the establishment of Substantial Equivalence have a clinical diagnosis of Lyme Disease based on the probability of exposure/infection (tick bite and/or patient presence in potential tick habitats in an endemic region within 30 days prior to the onset of EM (erythema migrans)), Borrelia isolation by culture (where possible), or, for non-EM patients, the presentation of Late Lyme clinical manifestations (e.g., cardiac, joint-involvement, or neurological symptoms).

Each of the clinical trial sites provided specimens that were wellcharacterized by the site using Lyme-specific serological analyses, including EIA and Western Blot testing.

Substantial equivalence of this device is based on the assessment of performance of the device in these clinical trials in which the wellcharacterized, archived Lyme Disease specimens, the Centers for Disease Control Lyme Disease Serum Panel, normal donor specimens (from endemic and non-endemic regions), and samples from diverse disease conditions were analyzed.

4. Description

During the incubation period, human antibodies specific to the B. burgdorferi antigens, if present in the sample or control, will bind to the

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antigen to which they have affinity. Unbound serum and non-specific antibodies are washed from the strip. Detection of bound IgG antibodies is accomplished by reacting and incubating the strips with a solution anti-human IgG antibodies conjugated with alkaline containing phosphatase. Unbound conjugate antibodies are removed by washing. The qualitative assessment of the detected IgG antibodies is then accomplished by the reaction of the alkaline phosphatase with a chemical substrate, which is cleaved into a colored, insoluble product that can be visualized. The determination of the reactivity of each unknown specimen is accomplished by comparison of the identified, visualized bands to the Band Identifying and Band Intensity Controls.

1. Intended Use
  The Cambridge Biotech Human Lyme B. burgdorferi IgG Western Blot is intended for use in testing human serum samples which have demonstrated positive or equivocal responses using EIA or IFA test procedures to provide supportive evidence of infection with Borrelia burgdorferi.

1. Performance Summary
  The report of the complete clinical trial for the Cambridge Biotech Human Lyme IgG kit is contained in this section. Data for IgG and IgM have not been interpreted together, but separately, as will be required in clinical settings.

From a summary of the clinical trial data, the following performance characteristics are described:

Specificity

Specificity of the device was determined from analysis of testing results of normal donor (from endemic and non-endemic regions) and disease specimens (1062 total samples) and was shown to be 100%, with 95% confidence intervals of 99.8% to 100.0%.

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Sensitivity

Sensitivity of the device was determined from analysis of test results of characterized Lyme disease specimens (287 total samples) that were drawn at different times after onset of disease:

Sensitivity of the Cambridge Biotech Human Lyme B. burgdorferi IgGWestern Blot Relative to Lyme Disease Clinical Diagnosis and Treatment including Results by Draw Time

DiseasePresentation	DrawTime(months)	TotalNumber ofSpecimens	NumberByDrawTime	Number ofSpecimensPositive	SpecimensPositiveBy DrawTime	Sensitivity	95% CL
BeforeTreatment	<1	97	95	20	18	21%	12.6-28.7%
	1-2		2		2
	2-12		0		0
AfterTreatment	<1	126	40	24	4	19%	12.2-25.9%
	1-2		48		13
	2-12		38		7
LymeLate	<1	64	0	56	0	88%	78.8-96.2%
	1-2		0		0
	2-12		64		56

The Draw Time is the time from disease onset to specimen collection. The specimens were taken from 169 individual patients. Second draws were done on 92 of the 169 patients, third draws were done on 36 of those patients. The specimens from patients under antibiotic treatment may interfere with positive results. Ten specimens that were tested for IgM, were not tested for IgG due to insufficient sample.

Precision

Six IgG Controls were tested in duplicate on each of three days at three test sites, totaling 18 replicates per control for all sites. All three sites were in 100% agreement for the disposition of the six IgG Controls. Additionally, all three sites were in 92% agreement as to the presentation of the IgG diagnostic band.

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Reproducibility

Ten positive and negative specimens from the CDC 47-member panel were tested at four sites. There was 100% agreement for the IgG disposition scores with the 20 specimens at all four sites. Eighty seven point five percent (87.5%) of the ten diagnostic bands of all 20 specimens were scored identically at all four test sites. In addition, a 94% overall agreement was shown between the scoring of positive lgG bands by the sites and the expected IgG band score results.

Site	Number ofCorrectBands	PercentageofCorrectBands	CorrectNumber ofInterpretations	Precentage ofCorrectInterpretations
Site 1	86/101	85%	20/20	100%
Site 2	98/101	97%	20/20	100%
Site 3	97/101	96%	20/20	100%
Site 4	97/101	96%	20/20	100%
Total	378/404	94%	80/80	100%

Agreement with Expected Results Across Four Sites

Determination of Threshold Intensity 7.

The threshold determination was originally performed by analysis of IgG sensitivity and specificity panels. The intensity of weakly reactive Lyme antibody-positive samples (n = 5) were compared to the intensities of highly reactive Lyme antibody-negative samples (n = 5) in preclinical testing to demonstrate that the threshold appropriately differentiated positive and negative specimens. The negative specimens included normal donor samples only. Subsequent lots of the Control have been approved based on continued demonstration of this characteristic.

8. Conclusions

Based on the clinical performance, this device has been shown to be safe and effective for the intended use in the qualitative detection of human Immunoglobulin G (IgG) antibodies in serum or plasma to Borrelia burgdorferi antigens, and as a supplemental, more specific, test to aid in the diagnosis of infection or exposure to Borrelia burgdorferi, the causative agent of Lyme disease.

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Image /page/5/Picture/2 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized caduceus, which is a symbol of medicine, with a single snake entwined around a staff. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES · USA" is arranged in a circular fashion around the caduceus.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

FEB 1 7 1998

Mr. Wole Edwin Director of Ouality Assurance and Regulatory Affairs Cambridge Biotech 1500 East Gude Drive Rockville, MD 20850-5307

Re: K971169

Trade Name: Cambridge Biotech Human Lyme Borrelia burgdorferi IgG Western Blot

Regulatory Class: II Product Code: LSR Dated: December 3, 1997 Received: December 3, 1997

Dear Mr. Edwin:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to 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). 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.

If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition. FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does no^ affect any obligation you might have under sections 531 through 542 of the Act for under the Electronic Product Radiation Control provisions, or other Federal lav regulations.

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Page 2

Under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88), this device may require a CLIA complexity categorization. To determine if it does, you should contact the Centers for Disease Control and Prevention (CDC) at (770)488-7655.

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4588. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll free number (800) 638-2041 or at (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html"

Sincerely yours,

Steven Sutman

Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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K971169 510(k) Number (if known):

Device Name: Cambridge Biotech Human Lyme Borrelia burgdorferi IgG Western Blot

Indications For Use:

The Cambridge Biotech Human Lyme B. burgdorferi IgG Western Blot can be used at any time following onset of symptoms. It should also be used for follow up when (1) only IgM antibodies were originally detected, (2) IgG antibodies were detected but were not considered significant, or (3) previously tested seronegative individuals are shown to develop antibodies by EIA or IFA test procedures.

The assay is not intended for use as a screening assay, nor should it be used for analysis of serum from patients who have not demonstrated symptoms of Lyme Disease.

(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)

J. Anmo

(Division Sign-Off)
Division of Clinical Laboratory Devices
510(k) Number. K971169

Concurrence of CDRH, Office Device Evaluation (ODE)

Prescription Use
(Per 21 CFR 801.109) ✓

Over-The-Counter Use

(Optional Format 1-2-96)

Regulation Number and Section

§ 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).