The Cambridge Biotech Human Lyme B. burgdorferi IgM Western Blot is an in vitro test system for the qualitative detection of human Immunoglobulin M (IgM) antibodies to Borrelia burgdorferi antigens in human serum. The Cambridge Biotech Human Lyme B. burgdorferi IgM 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 IgM Western Blot can be used during the acute phase (0-4 weeks of symptoms onset) of B. burgdorferi infection. After this period, infected patients are usually found to be Western Blot positive for IgG. A positive IgM test alone is not recommended for use in determining active disease in persons with illness of longer than one month.

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 neqative 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 IgM antibodies is accomplished by reacting and incubating the strips with a solution containing anti-human IgM antibodies conjugated with alkaline phosphatase. Unbound conjugate antibodies are removed by washing. The qualitative assessment of the detected IgM 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

Here's an analysis of the provided 510(k) summary regarding the Cambridge Biotech Borrelia burgdorferi Human Lyme IgM Western Blot kit:

Acceptance Criteria and Device Performance Study

1. Table of Acceptance Criteria and Reported Device Performance

The 510(k) summary does not explicitly state pre-defined acceptance criteria with specific numerical targets for sensitivity, specificity, precision, or reproducibility. Instead, it presents the achieved performance characteristics from the clinical trial. However, we can infer that the reported values met the implicit criteria for substantial equivalence.

Performance Metric	Acceptance Criteria (Implied)	Reported Device Performance	Comments on Acceptability
Specificity	Sufficiently high to minimize false positives	97.5% (95% CI: 96.6% to 98.5%)	Met, considered high.
Sensitivity	Sufficiently high for detection in relevant patient populations	Overall (Mixed Draw Times/Treatment): 57% (Before Treatment, 0-2 months), 64% (After Treatment, 0-2 months), 39% (Lyme Late, 0-12 months)	Met, but noted variability based on disease stage and treatment. Specificity appears to be prioritized.
Precision	100% agreement between sites and within sites for controls	100% agreement across three sites for disposition of 6 IgM controls and 3 diagnostic bands.	Met, excellent consistency.
Reproducibility	High agreement between sites for positive/negative scores and band scoring	100% agreement for IgM disposition scores (20 specimens) across four sites. 86.7% agreement for 3 diagnostic bands across sites. 94% overall agreement with expected IgM band scores.	Met, very good inter-site consistency.

2. Sample Sizes Used for the Test Set and Data Provenance

Specificity Test Set: 1062 total samples
- Data Provenance: Normal donor specimens (from endemic and non-endemic regions) and disease specimens. The document doesn't specify the exact countries of origin but mentions endemic and non-endemic regions, suggesting geographical diversity. It is retrospective, as these were "well-characterized, archived Lyme Disease specimens" and samples from diverse disease conditions.
Sensitivity Test Set: 296 total characterized Lyme disease specimens.
- Data Provenance: "Characterized Lyme disease specimens" drawn at different times after onset of disease. These specimens came from "169 individual patients." Second draws were done on 92 patients, and third draws on 36 patients. Clinical diagnosis of Lyme Disease was based on "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." Specimens were provided by "clinical trial sites" and "well-characterized by the site using Lyme-specific serological analyses, including EIA and Western Blot testing." This data is retrospective.
Precision Test Set: Six IgM Controls, tested in duplicate on each of three days at three test sites.
Reproducibility Test Set: Ten positive and ten negative specimens from the CDC 47-member panel (total 20 specimens), tested at four sites.

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

The document does not explicitly state the number of experts used to establish the ground truth or their specific qualifications (e.g., radiologist with X years of experience). However, it notes that:

"characterized samples used for the establishment of Substantial Equivalence have a clinical diagnosis of Lyme Disease" based on specific criteria (exposure, EM, culture, Late Lyme symptoms).
"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 that medical professionals (likely physicians specializing in infectious diseases, and laboratory professionals performing serological analyses) at the clinical trial sites established the clinical diagnoses and characterization, which served as the ground truth. Specific credentials or numbers are not provided.

4. Adjudication Method for the Test Set

The document does not explicitly describe an adjudication method for the test set results (e.g., 2+1, 3+1 consensus). The clinical diagnosis and characterization by individual sites appear to have served as the ground truth. For precision and reproducibility, results were compared across multiple sites, with agreement percentages reported, suggesting a comparison or consensus model rather than a formal adjudication process described for initial ground truth establishment.

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

No, an MRMC comparative effectiveness study comparing human readers with and without AI assistance was not done. This device is an in-vitro diagnostic (IVD) kit for laboratory use, not an AI-assisted diagnostic tool. Therefore, the concept of "human readers improve with AI vs. without AI" is not applicable here.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study Was Done

Yes, the performance study effectively evaluates the device in a standalone manner. The reported sensitivity, specificity, precision, and reproducibility values reflect the performance of the IgM Western Blot kit itself, as interpreted by laboratory personnel following the kit's instructions. While human technicians read the visualized bands, the "algorithm" is the Western Blot test itself, and its performance is reported independently of any additional human diagnostic steps beyond the qualitative assessment of the bands per the kit's comparison method. The human interpretation of the bands is integral to the "device performance."

7. The Type of Ground Truth Used

The ground truth used was a combination of:

Clinical Diagnosis: Based on "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 (ervthema 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)."
Lyme-Specific Serological Analyses: Including EIA and Western Blot testing performed by the clinical trial sites themselves.
CDC Lyme Disease Serum Panel: Used for reproducibility testing, which represents a highly characterized reference panel.

This is primarily a combination of expert clinical consensus and established serological test results from the providing sites.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" in the context of machine learning or algorithm development. For this type of IVD, the development and optimization of the assay (e.g., protein fractionation, antibody concentrations, detection methods) are iterative processes that precede the clinical validation. The "threshold determination" (Section 7) used a preclinical testing set of 3 weakly reactive positive samples and 10 highly reactive negative samples, which could be considered an internal "optimization/training" set for establishing cut-offs.

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

As noted above, for the "threshold determination" set:

Preclinical Testing: The ground truth for these samples was presumably established during the assay development by comparing "weakly reactive Lyme antibody-positive samples" to "highly reactive Lyme antibody-negative samples." The characteristics of these samples (positive/negative for Lyme antibodies) would have been determined using established laboratory methods and clinical knowledge during the product development phase. The "negative specimens included both normal donors and samples from patients with potentially cross-reactive conditions or infections," indicating a robust characterization.

Summary

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K971170

Section 12 510(k) SUMMARY

Submitted By:

FEB 17 1998

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 19 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

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2. Product Name

Trade Name:	Cambridge Biotech Borrelia burgdorferiHuman Lyme IgM Western Blot kit
Common Name:	Lyme IgM 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 (ervthema 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

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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 IgM antibodies is accomplished by reacting and incubating the strips with a solution containing anti-human IgM antibodies conjugated with alkaline phosphatase. Unbound conjugate antibodies are removed by washing. The qualitative assessment of the detected IgM 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.

5. Intended Use

The Cambridge Biotech Human Lyme B. burgdorferi IgM Western Blot is. an in vitro test system for the qualitative detection of human Immunoglobulin M (IgM) antibodies to Borrelia burgdorferi antigens in human serum. The Cambridge Biotech Human Lyme B. burgdorfen IgM 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 IgM Western Blot can be used during the acute phase (0-4 weeks of symptoms onset) of B.
burgdorferi infection. After this period, infected patients are usually found
to be Western Blot posit recommended for use in determining active disease in persons with illness of longer than one month.

Performance Summary റ.

The report of the complete clinical trial for the Cambridge Biotech Human Lyme IgM 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.

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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 97.5%, with 95% confidence intervals of 96.6% to 98.5%.

Sensitivity

Sensitivity of the device was determined from analysis of test results of characterized Lyme disease specimens (296 total samples) that were drawn at different times after onset of disease:

Sensitivity of the Cambridge Biotech Human Lyme B. burgdorferi lgM Western Blot

Relative to Lyme Disease Clinical Diagnosis and Treatment including Results by Draw Time

DiseasePresentation	DrawTime(months)	TotalNumber ofSpecimens	NumberBy DrawTime	Number ofSpecimensPositive	SpecimensPositiveBy Draw Time	Sensitivity	95%CL
BeforeTreatment	<1		100		56
BeforeTreatment	1-2	102	2	58	2	57%	47.3-66.5%
BeforeTreatment	2-12		0		0
AfterTreatment	<1		40		27
AfterTreatment	1-2	131	51	84	35	64%	55.9-72.3%
AfterTreatment	2-12		40		22
LymeLate	<1		0		0
LymeLate	1-2	64	0	25	0	39%	27.1-51.0%
LymeLate	2-12		64		25

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.

Precision

Six IgM 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 IgM Controls. Additionally, all three sites were in 100% agreement for the three diagnostic bands (p41, p39, and p23) for all six controls on every day of testing.

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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 IgM disposition scores with the 20 specimens at all four sites. Eighty six point seven percent (86.7%) of the three 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 IgM bands by the sites and the expected IgM band score results.

Site	Number ofCorrect Bands	Percentage ofCorrect Bands	Correct Number ofInterpretations	Percent(%)
Site 1	25/27	93%	20/20	100
Site 2	25/27	93%	20/20	100
Site 3	26/27	96%	20/20	100
Site 4	25/27	93%	20/20	100
Total	101/108	94%	80/80	100

Agreement with Expected Results Across Four Sites

7. Determination of Threshold Intensity

The threshold determination was originally performed by analysis of IgM sensitivity and specificity panels. The intensity of weakly reactive Lyme antibody-positive samples (n = 3) were compared to the intensities of highly reactive Lyme antibody-negative samples (n = 10) in preclinical testing to demonstrate that the threshold appropriately differentiated positive and negative specimens. The negative specimens included both normal donors and samples from patients with potentially cross-reactive conditions or infections. The p41 band was chosen as the intensity indicator for all bands except p23. The p23 band is used to score p23 bands, due to its diffuse nature. 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 M (IgM) 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/1 description: The image is a black and white seal for the Department of Health & Human Services - USA. The seal is circular with the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" written around the perimeter. In the center of the seal is an abstract image of an eagle.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

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

FEB 17 1998

Re: K971170

Trade Name: Cambridge Biotech Human Lyme Borrelia burgdorferi IgM Western Blot Kit 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 not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or 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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Section 8 Statement of Indications for Use

510(k) Number (if known):

Cambridge Biotech Human Lyme Borrelia burdorferi IgM Device Name: Western Blot Kit

Indications For Use:

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

Concurrence of CDRH, Office Device Evaluation (ODE)

Prescription Use	✓
(Per 21 CFR 801.109)

Over-The-Counter Use

Ue How 2/17
Division Sign-Off

Division of Clin oratory Devices (Optional Format 1-2-96)

510(k) Number

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).