This enzyme-linked immunosorbent assay (ELISA) is indicated for the detection and measurement of circulating IgM antibodies to ß2 Glycoprotein in human serum. The presence of these antibodies, in combination with clinical observations and other serological tests, can aid in the diagnosis of Primary and Secondary Antiphospholipid Syndrome.

Device Description

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of IgM antibodies to ß, Glycoprotein I in human serum. The ELISA methodology is commonly used for serum antibody evaluations. Purified human ß, glycoprotein has been attached to the inner surfaces of the microwell plate. During the initial incubation step, specific antibodies in patient serum will bind to the antigen and are immobilized on the surface. After incubation and a wash step, a peroxidase labeled anti human IgM (u chain specific) second antibody is added to the wells to react with the immobilized anti beta 2 GP1 antibodies. After incubation and another wash step, the substrate is added. In the wells where the specific antigenantibody-HRP complex remains bound, the peroxidase enzyme catalyzes a color change in the substrate. After the enzymatic reaction is stopped, the colored product is read in an EIA plate reader at a specified wavelength.

AI/ML Overview

Here's a breakdown of the acceptance criteria and study information based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state formal "acceptance criteria" in terms of pre-defined thresholds for sensitivity, specificity, or agreement. Instead, it presents performance results from various studies and concludes that these results "support the claim that the proposed device is capable of effectively detecting IgM antibodies to ß₂ Glycoprotein I in human serum."

Therefore, the table below reflects the reported performance without specific pre-stated acceptance criteria being identified:

Performance Metric	Reported Performance (VIRGO® β₂ Glycoprotein I IgM Antibody Kit)
Precision
Inter-Assay % C.V. (Range)	2.3% - 13.9% (for various samples and calibrator dilutions)
Intra-Assay % C.V. (Range)	8.2% - 10.7% (for various samples)
Clinical Performance
Relative Sensitivity	87.9% (95% CI: 79.6% to 93.1%) compared to aCL IgM
Relative Specificity	96.5% (95% CI: 90.4% to 98.8%) compared to aCL IgM
Relative Agreement	93.3% (95% CI: 86.2% to 96.9%) compared to aCL IgM
Prevalence in APS1	62.8% (43 samples)
Prevalence in SLE + APS	57.1% (7 samples)
Prevalence in RA	0% (40 samples)
Prevalence in SLE (No APS)	5.0% (20 samples)
Prevalence in Scl-70	0% (20 samples)
Prevalence in Infectious	2.5% (40 samples)
Prevalence in Normals	0% (120 samples)

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

Sample Size for Performance Testing (Clinically Characterized Serum Samples):
- APS1: 43 samples
- SLE + APS: 7 samples
- Rheumatoid Arthritis: 40 samples
- SLE (No APS): 20 samples
- Scl-70 (No APS): 20 samples
- Infectious: 40 samples
- Normals: 120 samples
- Total for this section: 290 samples
Sample Size for Comparison with aCL IgM:
- Clinically characterized APS serum samples: 50 samples
- Apparently healthy donors: 40 samples
- Total for this section: 90 samples
Data Provenance: The document does not explicitly state the country of origin. It describes the data as "clinically characterized serum samples" and samples from "individuals diagnosed with Primary APS and other diseases." This indicates the data is retrospective as samples were already characterized.

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

The document does not specify the number of experts or their qualifications used to establish the ground truth for the test set. It only states that the samples were "clinically characterized" and from "individuals diagnosed" with specific conditions.

4. Adjudication Method for the Test Set

The document does not describe any adjudication method for the test set. The ground truth seems to be based on prior clinical diagnosis.

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 in-vitro diagnostic (ELISA) kit and thus does not involve human readers interpreting images or data to the same extent as an AI device. The comparison was with another diagnostic test (aCL IgM).

6. If a Standalone Performance Study was Done

Yes, a standalone performance study was done. The precision studies (inter and intra-assay) and clinical performance testing against various patient groups (APS, SLE, RA, etc.) demonstrate the standalone performance of the VIRGO® β₂ Glycoprotein I IgM Antibody Kit. The "Comparison with aCL IgM" section also evaluates the device's performance in relation to a predicate, which can be seen as a form of standalone evaluation against established diagnostic methods.

7. The Type of Ground Truth Used

The ground truth used was clinical diagnosis and characterization of serum specimens. The samples were described as "clinically characterized serum samples" and from "individuals diagnosed with Primary APS and other diseases." For the comparison with aCL IgM, the ground truth for "APS" was based on clinical characterization, and "healthy donors" for the negative group.

8. The Sample Size for the Training Set

The document does not provide information regarding a separate training set. For in-vitro diagnostic kits like this, the development process typically involves internal validation and optimization, but a distinct "training set" for an AI algorithm is not applicable here. The performance data presented is generally for validation purposes.

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

As there is no explicit training set discussed in the context of an AI algorithm, the method for establishing ground truth for a training set is not applicable or described in this document. The development of such ELISA kits relies on standardizing reagents and methods, and validating performance against clinically defined samples.

Summary

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510(k) Summary

K992243

Submitter's Name/Contact Person 1.

Joseph M. Califano Director, Regulatory Affairs

Address

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

(781) 890-3766 x 257 Phone: (781) 890-3748 Fax: jcalifano@hemagen.com email:

Date Prepared

14 June 1999

Date Revised

25 August 1999

2. Device Name

Trade Name:	VIRGO® β₂ Glycoprotein I IgM Antibody Kit
Common Name:	β₂ Glycoprotein I Antibodies Test System
Classification Name:	Multiple Autoantibodies Immunological Test System

3. Predicate

Trade Name: 510 (k) Docket No. Hemagen ® Cardiolipin Antibody Kit Hemagen ® Cardiolipin Antibody Kit
K 932373, SE Date; 16 July 1993,

The performance of the VIRGO® B, Glycoprotein I Igg Antibody Kit was also evaluated with a panel of characterized serum specimens from individuals diagnosed with Primary APS and other diseases.

510 (k) Summary Page 1

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3. Description of Device

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of IgM antibodies to ß, Glycoprotein I in human serum.

The ELISA methodology is commonly used for serum antibody evaluations. Purified human ß, glycoprotein has been attached to the inner surfaces of the microwell plate. During the initial incubation step, specific antibodies in patient serum will bind to the antigen and are immobilized on the surface. After incubation and a wash step, a peroxidase labeled anti human IgM (u chain specific) second antibody is added to the wells to react with the immobilized anti beta 2 GP1 antibodies. After incubation and another wash step, the substrate is added. In the wells where the specific antigenantibody-HRP complex remains bound, the peroxidase enzyme catalyzes a color change in the substrate. After the enzymatic reaction is stopped, the colored product is read in an EIA plate reader at a specified wavelength.

4. Intended Use of Device

This enzyme-linked immunosorbent assay (ELISA) is intended for the detection and measurement of IgM antibodies to B, Glycoprotein I in human serum.

5. Technological Characteristics

Proposed Device

The VIRGO® ® ß, Glycoprotein I IgM Antibody 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. The device also contains a IgM Calibrator to enable the assignment of arbitrary IgM antibody values to patient samples.

Predicate Device

The Hemagen ® Cardiolipin IgG/IgM Antibody 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. The device also contains both an IgM Calibrator, and an IgG Calibrator to enable the assignment of MPL or GPL unit values to patient samples. The calibrators have been standardized to the IgM and IgG standards obtained from Louisville APL Diagnostics, Inc.

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5. Performance Data

Precision

To estimate the overall precision of the VIRGO ® ß, Glycoprotein I IgM Antibody Kit, inter, and intra assay studies were conducted. The results of these studies is summarized in the tables below

Inter Assay

Three serum samples, the Negative, and Positive Controls, and the Calibrator were assayed five times each, twice a day, on five different days :

	Mean RMU	Std. Deviation	% C.V.
Sample 1	131.5	16.2	12.3
Sample 2	57.7	8.0	13.9
Sample 3	11.4	1.2	10.7
Neg. Control	< 10	N/A	N/A
Pos. Control	71.0	8.1	11.4
Cal Dil 1	154.4	4.3	2.8
Cal Dil 2	80.3	3.4	4.2
Cal Dil 3	40.2	2.4	5.9
Cal Dil 4	20.0	0.8	3.9
Cal Dil 5	10.4	0.2	2.3

Intra Assay

The same three serum samples were assayed ten consecutive times in duplicate:

	Mean RMU	Std. Deviation	% C.V.'
Sample 1	106.7	11.5	10.7
Sample 2	52.8	4.3	8.2
Sample 3	< 10	N/A	N/A

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Performance Testing

To demonstrate the effectiveness of the device, a number of clinically characterized serum samples were tested. The results are summarized in the table below:

Patient Group	Number	Number Positive (%)
APS1	43	27(62.8)
SLE + APS	7	4 (57.1)
Rheumatoid Arthritis	40	0 (0)
SLE (No APS)	20	1 (5.0)
Scl-70 (No APS)	20	0 (0)
Infectious2	40	1 (2.5)
Normals	120	0 (0)

Notes

APS = Antiphospholipid syndrome 1.

The infectious group consisted of samples with positive syphilis serology.

Comparison with aCL IgM

The 50 clinically characterized APS serum samples, and 40 serum samples from apparently healthy donors were evaluated with the VIRGO® B, Glycoprotein I IgM Antibody Kit, and a commercially available anti-cardiolipin IgM EIA. The results are summarized in the table below

aCL IgM

		Positive	Negative
IgM β₂ GPI	Positive	29	2
	Negative	4	55
TOTAL		33	57
Relative Sensitivity: 87.9 %: {79.6 to 93.1 %; 0.95 Confidence Interval}
Relative Specificity: 96.5 %: {90.4 to 98.8 %; 0.95 Confidence Interval}
Relative Agreement: 93.3 %: {86.2 to 96.9 %; 0.95 Confidence Interval}

097774

510(k) Summary Page 4

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Conclusion

The results of the both the comparative studies with the predicate device and the performance studies utilizing clinically characterized serum specimens support the claim that the proposed device is capable of effectively detecting IgM antibodies to ߿Glycoprotein I in human serum.

510(k) Summary Page 5

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Image /page/5/Picture/1 description: The image shows the seal of the U.S. Department of Health & Human Services. The seal features the department's name in a circular arrangement around a stylized depiction of a human figure. The figure is composed of three abstract shapes that suggest a profile view of a person. The text reads "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA".

AUG 30 1999

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Mr. Joseph M. Califano Director, Regulatory Affairs Hemagen Diagnostics, Inc. 34-40 Bear Hill Road Waltham, Massachusetts 02154

K992243 Re:

Trade Name: VIRGO® ß, Glycoprotein I IgM Antibody Kit Regulatory Class: II Product Code: MSV Dated: June 14, 1999 Received: July 1, 1999

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 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). 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 (301) 443-6597, or at its internet address "http://www.fda.gov/cdrh/dsma/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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VIRGO ® ß2 Glycoprotein I IgM Antibody Kit Device Name:

Indication(s) For Use

(PLEASE DO NOT WRITE BELOW THIS LINE)

Concurrence of CDRH, Office of Device Evaluation (ODE)

Lester E. Mdress

(Division Sign-Off)
Division of Clinical Laboratory Devices
510(k) Number K99224

Prescription Use
(Per 21 CFR 801.109)
✓

・・(

Over-The-Counter-Use

Regulation Number and Section

§ 866.5660 Multiple autoantibodies immunological test system.

(a)
Identification. A multiple autoantibodies immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoantibodies (antibodies produced against the body's own tissues) in serum and other body fluids. Measurement of multiple autoantibodies aids in the diagnosis of autoimmune disorders (disease produced when the body's own tissues are injured by autoantibodies).(b)
Classification. Class II (performance standards).