This enzyme-linked immunosorbent assay (ELISA) is indicated for the detection and measurement of antimitochondrial antibodies in human serum. The presence of mitochondrial antibodies, in combination with clinical observations and other serological tests, can aid in the diagnosis of primary biliary cirrhosis(PBC)

Device Description

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of antibodies to mitochondrial antigen in human serum. The ELISA methodology is commonly used for serum antibody evaluations. Purified mitochondrial antigen has been attached to the inner surfaces of the microwell plate. During the initial incubation step, antibodies in patient serum bind specifically to the immobilized antigen and remain in place after a wash step. A second antibody which is conjugated to horseradish peroxidase (HRP) is used to recognize the "heavy + light" chain regions of the patient's antibodies remaining after the wash step. In the wells where the second antibody remains bound, the conjugated HRP catalyzes a color change in the substrate, tetramethyl benzidine (TMB). After the reaction is stopped, the color is read in an EIA Plate reader.

AI/ML Overview

The provided document describes the VIRGO® AMA ELISA KIT, an enzyme-linked immunosorbent assay designed for the detection and measurement of antimitochondrial antibodies in human serum. This device is intended to aid in the diagnosis of primary biliary cirrhosis (PBC) when used in combination with clinical observations and other serological tests.

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria with numerical targets. However, based on the comparative testing and precision studies, the implied criteria are:

Acceptance Criteria Category	Implied Acceptance Criteria (Based on context)	Reported Device Performance (VIRGO® AMA ELISA KIT)
Precision (Inter-assay)	Demonstrates consistency across different assays	Mean % CV for positive samples (OD): 4.9 - 11.0%
		Mean % CV for positive samples (Units): 9.9 - 15.9%
		Negative samples: N/A due to low OD values.
Precision (Intra-assay)	Demonstrates consistency within a single assay run	Mean % CV for positive samples (OD): 2.7 - 8.5%
		Mean % CV for positive samples (Units): 9.1 - 13.7%
		Negative samples: N/A due to low OD values.
Comparative Testing (Sensitivity)	High agreement with predicate device for positive samples from individuals with known or suspected liver disease.	Relative Sensitivity = 100.0% (61/61) with 94.1% to 100% confidence interval.
Comparative Testing (Specificity)	High agreement with predicate device for negative samples from apparently healthy donors.	86 out of 86 normal samples were negative, indicating 100% agreement with the predicate device for this cohort.
Interfering Substances	No significant effect (<15% variation) on assay results due to common interfering substances.	Hemoglobin (<500 mg/dL): No significant effect.
		Bilirubin (≤20 mg/dL): No significant effect.
		Lipid (<3000 mg/dL): No significant effect.
Prozone Effect	No unexpectedly low values for high-titered serum samples.	Kit gives appropriately high positive results with high-titered sera.

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

Precision Studies:
- Inter-assay: 12 different samples (9 positive, 3 negative).
- Intra-assay: The same 12 samples (9 positive, 3 negative).
- Data Provenance: Not specified, but likely from a laboratory setting. No country of origin is mentioned. The studies are prospective in nature to evaluate device performance.
Comparative Testing:
- Total Test Set Size: 154 serum specimens.
- Breakdown: 68 specimens from individuals with known or suspected liver disease and 86 from normal, apparently healthy donors.
- Data Provenance: Not specified, but likely from a clinical or laboratory setting. No country of origin is mentioned. These are retrospective samples as they are "known" cases or "normal" donors.

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

The document does not explicitly mention the use of "experts" to establish ground truth in the typical sense of subjective interpretation (e.g., radiologists). Instead, the "ground truth" for the comparative testing is based on:

Predicate Device Results: The Scimedx Mitochondrial Antibody Test System is used as the comparative standard.
Clinical Status: 68 samples were from "individuals with known or suspected liver disease," and 86 were from "normal apparently healthy donors." This implies clinical diagnosis or health status was used for initial classification.

Therefore, the ground truth is established by a combination of a legally marketed predicate device's results and, for the clinical samples, presumably by physician diagnosis based on clinical observations and other serological tests. No specific number of experts or their qualifications for establishing human ground truth are provided, as the method relies on objective test results and clinical status.

4. Adjudication Method for the Test Set

No explicit adjudication method (e.g., 2+1, 3+1) is mentioned. The comparison testing directly compares the proposed device's results against the predicate device's results. For the clinical samples, the "known or suspected liver disease" and "normal" classifications serve as the basis, implying that a clinical consensus or established diagnostic criteria were already in place for those classifications. However, no specific adjudication of discrepant results between the proposed device and the predicate device is detailed beyond the direct numerical comparison shown in the tables.

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

No, an MRMC comparative effectiveness study was not done. This device is an immunoassay (ELISA kit), which produces objective numerical optical density (OD) readings that are then interpreted against a fixed cutoff to determine a positive or negative result. It does not involve human readers interpreting images or data in a subjective manner that would necessitate an MRMC study to evaluate human performance with or without AI assistance.

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

Yes, the performance presented for the VIRGO® AMA ELISA KIT is a standalone performance. The device is a laboratory assay where samples are processed, and the results (optical density readings) are automatically generated and interpreted against a predetermined cutoff value without human interpretation or intervention in the diagnostic decision of the device itself. The results are then reported as positive or negative. The listed "Relative Sensitivity" is a standalone metric.

7. The Type of Ground Truth Used

The ground truth used for performance evaluation is primarily:

Predicate Device Results: For direct comparison and performance evaluation, the results from the legally marketed Scimedx Mitochondrial Antibody Test System serve as the gold standard or reference.
Clinical Diagnosis/Outcomes Data: For the 68 "known or suspected liver disease" specimens and 86 "normal apparently healthy donors," the ground truth is based on established clinical diagnoses or health status, which would derive from a combination of patient history, physical examination, and other laboratory/imaging findings (i.e., outcomes data in a broader sense).

8. The Sample Size for the Training Set

The document does not specify a separate "training set" or "training set size." Immunoassays like ELISA kits are typically developed and optimized through laboratory research and development, rather than machine learning training on a discrete dataset in the way an AI algorithm might be. The performance data presented (precision and comparative testing) pertains to the validation of the finalized device.

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

Since there is no explicitly mentioned "training set" in the context of machine learning, the concept of establishing ground truth for a training set does not directly apply. The development of an ELISA kit involves selecting and optimizing reagents, antigen concentrations, and establishing a cutoff value. This iterative process of optimization would rely on known positive and negative controls and clinically characterized samples to ensure the assay performs as intended. However, the specific methods for establishing ground truth during this development phase are not detailed in this 510(k) summary.

Summary

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K971909

JUN 20 1997

510(k) Summary

Submitter's Name/Contact Person 1.

Joseph M. Califano, Regulatory Affairs Manager

Address

Hemagen Diagnostics, Inc. 34-40 Bear Hill Road Waltham, MA, 02154

(617) 890-3766 Phone: (617) 890-3748 Fax: email: jcalifano@hemagen.com

Date Prepared

19 May 1997

2. Device Names

Trade Name: VIRGO ® AMA ELISA KIT Common Name: Antimitochondrial antibody Kit (EIA method) Classification Name: Antimitochondrial antibody immunological test system

3. Predicate Device

Scimedx Mitochondrial Antibody Test System.

000001

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3. Description of Device

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of antibodies to mitochondrial antigen in human serum.

The ELISA methodology is commonly used for serum antibody evaluations. Purified mitochondrial antigen has been attached to the inner surfaces of the microwell plate. During the initial incubation step, antibodies in patient serum bind specifically to the immobilized antigen and remain in place after a wash step.

A second antibody which is conjugated to horseradish peroxidase (HRP) is used to recognize the "heavy + light" chain regions of the patient's antibodies remaining after the wash step. In the wells where the second antibody remains bound, the conjugated HRP catalyzes a color change in the substrate, tetramethyl benzidine (TMB). After the reaction is stopped, the color is read in an EIA Plate reader.

4. Intended Use of Device

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of antibodies to mitochondrial antigen in human serum.

5.(A) Technological Characteristics

Proposed Device

The VIRGO ® AMA ELISA KIT is an enzyme-linked immunosorbent assay. The device utilizes optical density as a measure of antibody presence, with an established cutoff between a positive and a negative reaction.

Predicate Device

The Scimedx Mitochondrial Antibody Test System is an indirect fluorescent antibody assay. The device utilizes the indirect method of fluorescent antibody staining. The resultant level of observed fluorescence is used to determine the presence or absence of antibodies.

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5.(B) Performance Data

Precision

To evaluate precision, both inter-assay and intra-assay studies were conducted. The results are summarized below:

A Inter-assay

Twelve different samples {9 positive and 3 negative} were assayed in triplicate twice a day for five different days.

Sample	Mean OD	Std. Dev.	% CV	Mean Units	Std. Dev.	% CV
1	1.721	0.102	5.9	8.5	0.8	9.9
2	1.714	0.111	6.5	8.4	0.9	10.6
3	1.574	0.093	5.9	7.8	0.9	11.4
4	1.116	0.092	8.2	5.5	0.6	11.4
5	0.939	0.083	8.8	4.6	0.7	15.9
6	0.858	0.081	9.5	4.2	0.6	13.6
7	0.729	0.045	6.2	3.6	0.4	12.2
8	0.679	0.033	4.9	3.3	0.3	10.1
9	0.673	0.074	11.0	3.3	0.3	10.1
10	0.020	0.019	N/A	0.1	0.1	N/A
11	0.025	0.025	N/A	0.1	0.1	N/A
12	0.027	0.015	N/A	0.1	0.1	N/A

The assay controls {Positive, Negative, & Cutoff Serum} were assayed concurrently in triplicate twice each day for each of the five days.

Sample	Mean OD	Std. Dev.	% CV
Negative Control	0.003	0.003	N/A
Positive Control	1.202	0.110	9.2
Cutoff Serum	0.205	0.024	11.6

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Precision

Intra-assay B.

The same twelve samples {9 positive and 3 negative} were assayed 20 times in a single run.

Sample	Mean OD	Std. Dev.	% CV	Mean Units	Std. Dev.	% CV
1	1.362	0.050	3.7	9.3	1.0	10.7
2	1.243	0.034	2.7	8.4	0.8	9.6
3	1.354	0.066	4.9	9.2	0.8	9.1
4	0.822	0.058	7.0	5.6	0.5	9.2
5	0.608	0.043	7.2	4.1	0.4	10.2
6	0.636	0.054	8.5	4.3	0.6	13.7
7	0.600	0.039	6.5	4.1	0.4	11.0
8	0.559	0.030	5.4	3.8	0.4	9.6
9	0.532	0.033	6.1	3.6	0.4	9.7
10	0.010	0.002	N/A	0.07	0.01	N/A
11	0.009	0.002	N/A	0.06	0.01	N/A
12	0.010	0.001	N/A	0.07	0.01	N/A

The assay controls {Positive and Cutoff Serum} were assayed concurrently 20 times.

Sample	Mean OD	Std. Dev.	% CV
Positive Control	1.047	0.040	3.8
Cutoff Serum	0.149	0.015	10.2

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Comparison Testing

Companson 1 estima
A total of 154 serum specimently assayed by both the production of the predicate
A total of 154 serum specitly books, were concurrently assayed by bellevi A total of 154 serum speciment (68 from individuals with known of the discussion,
86 from normal apparently healthy donos) were concurrently assayed by both the follow: A total 01 104 Solan of 104 series are presented in the tables that he mail more.
device and the proposed device. The results are presented in the tables that more.

Table 1 Combined known or suspected liver disease specimens. n = 68

	Predicate Device
	Positive	Negative	Total
Proposed Device
Positive	61	0	61
Negative	0	7	7
Total	61	7	68

relative Sensitivity = 100.0 % {61/61}, ... confidence interval = 94.1% to 100 %
Relative Sensitivity = 100.0 % {61/61}, ... confidence interval = 94.1% to 100 %
{{ if(

Table 2 Normals. n = 86

Predicate Device

	Negative	Total
Proposed DevicePositive	0	0
Negative	86	86
Total	86	86

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Interfering Substances

Lipemic, icteric, and hemolytic samples were evaluated with the assay following Elpenine, and nemoryto bampio "interference Testing in Clinical NGCCS Document E. The results indicate that there is no significant effect (<15 % variation) on the assay for samples with:

Hemoglobin concentration: Bilirubin concentration: Lipid concentration:

< 500 mg/dL ≤ 20 mg/dL < 3000 mg/dL

Prozone

The VIRGO ® AMA ELISA Kit was used to assay several high titered serum samples to determine if the kit would return unexpectedly low values. The results of this evaluation indicate that the kit gives appropriately high positive results with high titered sera.

Conclusions

The results of the comparative studies support the claim that the proposed device is substantially equivalent to the predicate device and performs as an effective screening assay.

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Image /page/6/Picture/1 description: The image shows the seal for the Department of Health & Human Services USA. The seal is circular, with the words "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" arranged around the perimeter. In the center of the seal is a stylized image of three human profiles facing right, with flowing lines beneath them.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

JUN 20 1007

Joseph M. Califano Manager, Regulatory Affairs HEMAGEN DIAGNOSTICS, INC. 34-40 Bear Hill Road Waltham, MA 02154

乐

Re: K971909 Name: VIRGO® AMA ELISA KIT Regulatory Class: II Product Code: 82 DBM Dated: May 19, 1997 Received: May 23, 1997

Dear Mr. Califano:

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 requirement, 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 Autman

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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( = HOMAGEN DI AGNUS ( LES ID:6178963748 rage 2/2 Device Name: VIRGO ® AMA ELISA KIT Indication(s) For Use This enzyme-linked immunosorbent assay (ELISA) is indicated for the detection and measurement of antimitochondrial antibodies in human serum. The presence of mitochondrial antibodies, in combination with clinical observations and other serological tests, can aid in the diagnosis of primary biliary cirrhosis(PBC) on of Clinical Laboratory Der (PLEASE DO NOT WRITE BELOW THIS LINE) Concurrence of CDRH, Office of Device Evaluation (ODE) rescription Use OR Over-The-Counter-Use Per 21 CFR 801.109)

Regulation Number and Section

§ 866.5090 Antimitochondrial antibody immunological test system.

(a)
Identification. An antimitochondrial antibody immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the antimitochondrial antibodies in human serum. The measurements aid in the diagnosis of diseases that produce a spectrum of autoantibodies (antibodies produced against the body's own tissue), such as primary biliary cirrhosis (degeneration of liver tissue) and chronic active hepatitis (inflammation of the liver).(b)
Classification. Class II (performance standards).