WIELISA ANTI-GBM TEST SYSTEM

K974169 · Wieslab AB · DBL · Feb 17, 1998 · Immunology

Device Facts

• Record ID: K974169
• Device Name: WIELISA ANTI-GBM TEST SYSTEM
• Applicant: Wieslab AB
• Product Code: DBL · Immunology
• Decision Date: Feb 17, 1998
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.5660
• Device Class: Class 2

Intended Use

The Wielisa anti-GBM Test Kit is an Enzyme Linked Immunosorbent Assay (ELISA) for the detection and semi-quantitation of IgG antibodies in human serum to GBM (glomerular basement membrane). The assay is used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of Goodpasture syndrome.

Device Story

Wielisa anti-GBM Test Kit is an ELISA for detecting IgG antibodies to GBM in human serum. Input: single serum specimen. Principle: microtiter wells coated with purified GBM antigen; patient antibodies bind to antigen; alkaline phosphatase-labeled anti-human IgG conjugate binds to patient antibodies; substrate solution added; color intensity measured as optical density (OD). Output: semi-quantitative results in arbitrary units calculated against a calibrator curve. Used in clinical laboratories by trained personnel. Results aid physicians in diagnosing Goodpasture syndrome.

Clinical Evidence

Clinical performance evaluated using 272 retrospective sera. Sensitivity for anti-GBM nephritis was 100% (60/60). Specificity was 100% for SLE, RA, and blood donors, and 96.9% for systemic vasculitis. Relative sensitivity/specificity compared to IFA (n=68) was 100% and 88.9% respectively. Relative sensitivity/specificity compared to alternate ELISA (n=122) was 92.7% and 100% respectively. Precision and linearity data provided.

Technological Characteristics

ELISA-based immunoassay; microtiter strips coated with purified GBM antigen; alkaline phosphatase-labeled anti-human IgG conjugate; colorimetric detection via substrate solution; optical density measurement; semi-quantitative output in arbitrary units.

Indications for Use

Indicated for the detection and semi-quantitation of IgG antibodies to glomerular basement membrane (GBM) in human serum as an aid in the diagnosis of Goodpasture syndrome.

Regulatory Classification

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).

Predicate Devices

• Immunoscan Anti-GBM ELISA Kit

Submission Summary (Full Text)

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K974169

Summary of Safety and Effectiveness Information anti-GBM Test Kit

FEB 1 7 1998

Wieslab AB Ideon Research Park S-223 70 Lund Sweden Contact person: Dr. Jorgen Wieslander Telephone: [phone] Date of preparation: Jan, 19 1998

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Description of Device: The Wielisa anti-GBM Test Kit is an enzyme-linked 11. immunosorbent assay (ELISA) for the detection and semi-quantitation of IgG antibodies to glomerular basement membrane(GBM) in human sera. The assay is used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of Goodpasture syndrome. FOR IN VITRO DIAGNOSTIC USE.

The wells of the microtiter strips are coated with purified GBM antigen. During the first incubation, specific antibodies in diluted serum, will bind to the antigen coating.

The wells are then washed to remove unbound antibodies and other components. A conjugate of alkaline phosphatase-labeled antibodies to human IgG binds to the antibodies in the wells in this second incubation.

After a further washing step, detection of specific antibodies is obtained by incubation with substrate solution. The amount of bound antibodies correlates to the color intensity and is measured in terms of absorbance (optical density (OD)). The absorbance is then calculated against a calibrator curve and the results are given in arbitrary units.

111. Predicate Device

The anti-GBM test is substantially equivalent to the Immunoscan Anti-GBM ELISA Kit. Equivalence is demonstrated by the following comparative results:

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Table 1. Clinical Sensitivity and Specificity. A total of 272 frozen retrospective sera with clinical characterization were assayed. The following table summerizes the data.

| Control and<br>Disease groups | Total<br>number | Negative<br><10 units | Equivocal<br>10-20 units | Positive<br>>20 units |
|-----------------------------------|-----------------|-----------------------|--------------------------|-----------------------|
| Blood donors: | 120 | 120 | 0 | 0 |
| Anti-GBM nephritis: | 62 | 0 | 2 | 60 |
| Systemic vasculitis:<br>WG and MP | 33 | 31 | 1 | 1 |
| SLE: | 40 | 40 | 0 | 0 |
| RA: | 17 | 17 | 0 | 0 |

WG = Wegener's granulomatosis,

GBM = glomerular basement membrane

Clinical Sensitivity (Equivocal samples excluded from calculations)

GBM = 60/60 = 100% *95% confidence interval = 95.0-100%

### Clinical Specificity (Equivocal samples excluded from calculations)

| WG + MP | = 31/32 | = 96.9% | 95% confidence interval = 90.7-100% |
|---------|-----------|---------|--------------------------------------|
| SLE | = 40/40 | = 100% | *95% confidence interval = 92.6-100% |
| RA | = 17/17 | = 100% | *95% confidence interval = 82.7-100% |
| Normals | = 120/120 | = 100% | *95% confidence interval = 97.5-100% |

The 95% confidence intervals were calculated using the normal method. *The 95% confidence intervals were calculated assuming one false positive.

MP = microscopic polyangjitis SLE = systemic lupus erythematosus RA = rheumatoid arthritis

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Table 2 A total of 68 frozen retrospective sera were assayed by the Wielisa anti-GBM ELISA and by IFA. The following table summarizes the relative sensitivity and specificity of the assay.

## Relative Sensitivity and Specificity of the Wielisa anti-GBM Kit Compared to GBM IFA

| | | Wielisa anti-GBM | | | |
|------------|----------|------------------|-----------|----------|-------|
| | | Positive | Equivocal | Negative | Total |
| GBM<br>IFA | Positive | 55 | 3 | 0 | 58 |
| | Negative | 1 | 1 | 8 | 10 |
| | Total | 56 | 4 | 8 | 68 |

Sera falling in the equivocal range were excluded from the following calculations

| | | 95% Confidence Interval |
|----------------------|-------------------|-------------------------|
| Relative Sensitivity | = 55/55 = 100.0 % | 94.6 - 100.0 %* |
| Relative Specificity | = 8/9 = 88.9 % | 67.9 - 100.0 % |
| Relative Accuracy | = 63/64 = 98.4 % | 95.3 - 100.0 % |

* The 95% confidence interval was calculated assuming one false negative.

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Table 3 A total of 122 frozen retrospective sera were assayed by the Wielisa anti-GBM ELISA and by an alternate commercial ELISA. The following table summarizes the relative sensitivity and specificity of the assay.

# Relative Sensitivity and Specificity of the Wielisa GBM Kit Compared to an Alternate ELISA

### GBM Wielisa

| | | Positive | Equivocal | Negative | Total |
|--------------------|-----------|----------|-----------|----------|-------|
| | Positive | 38 | 0 | 3* | 41 |
| Alternate<br>ELISA | Equivocal | 2 | 0 | 7 | 9 |
| | Negative | 0 | 0 | 72 | 72 |
| | Total | 40 | 0 | 82 | 122 |

Sera falling in the equivocal range were excluded from the following calculations

| | | 95% Confidence Interval |
|----------------------|--------------------|-------------------------|
| Relative Sensitivity | = 38/41 = 92.7 % | 84.6 - 100 % |
| Relative Specificity | = 72/72 = 100 % | 95.9 - 100 %** |
| Relative Accuracy | = 110/113 = 97.4 % | 94.3 - 100 % |

* All three samples were from normal healthy patients.

** One false positive was included in this calculation.

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## Table 4. Batch to batch variation.

Batch to batch variation was determined by testing four different samples in duplicate. Results were obtained for four different batches.

| Sample | Mean value | SD | CV % |
|--------|------------|-----|------|
| 1 | 16 units | 2.9 | 17.7 |
| 2 | 42 units | 2.4 | 5.7 |
| 3 | 67 units | 2.1 | 3.1 |
| 4 | 134 units | 9.6 | 7.2 |

### Table 5. Inter-assay precision.

Inter-assay precision was determined by testing two different samples in duplicate. Results were obtained for six different runs.

.

| The Court of Children College of Children Collection of Children Company of Children Company of Children Company of Children Company of Children Company of Children Company o<br>Sample | .<br>Mean value | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------<br>SD | CV % | |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------|--|
| | 46 units | 1. 6 7 | 3.0 | |
| | 154 units<br>Comprehensive and the control of the control of the comments of the comments of the comments of the first and | 14.2 | 0 7<br>7.6<br>LAND SHEET LILL FURLER & SHEET | |

### Table 6. Intra-assay precision.

| Intra-assay precision was determined by testing one sample in 80 wells. | | | | | | | |
|-------------------------------------------------------------------------|------------|--------|------|--|--|--|--|
| Sample | Mean value | SD | CV % | | | | |
| | 77 units | 19 (8) | 10 | | | | |

#### Table 7. Linearity

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The values were determined for serial two-fold dilutions of six positive sera. The values were compared to log2 of dilution by standard linear regression. The data in Table 7 indicates that the assay has a linear relationship with serum dilution.

| Serum | Neat | 1:2 | 1:4 | 1:8 | 1:16 | 1:32 | 1:64 | r |
|-------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----|-------|-----|------|------|------|-------|
| 】 | 51 | 28 | 14 | રે | | | | 0.979 |
| 2 | 90 | રતે | રે રે | 20 | 00 | | | 0.981 |
| 3 | 293 | 143 | રે ર | 52 | 48 | 25 | ರಿ | 0.862 |
| 4 | 49 | 32 | 16 | ર | | | | 0.994 |
| ર | રેતે જેવી સવલતો પ્રાપ્ય થયેલી છે. આ ગામનાં પ્રાથમિક શાળા, પંચાયતઘર, આંગણવાડી તેમ જ દૂધની ડેરી જેવી સવલતો પ્રાપ્ય થયેલી છે. આ ગામનાં લોકોનો મુખ્ય વ્યવસાય ખેતી, ખેતમજૂરી તેમ જ | 39 | 28 | 23 | 】】 | | | 0.976 |
| 6 | 291 | 92 | 67 | 49 | 23 | 11 | 7 | 0.823 |

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Image /page/5/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo is circular and contains the text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" around the perimeter. In the center of the circle is an abstract symbol that resembles an eagle or other bird in flight.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

WEISLAB AB William L. Boteler c/o IMMUNO PROBE, INC. 1306 Bailes Lane, Suite F 21701 Frederick, MD

FEB 1 7 1998

Re: K974169 Trade Name: Wielisa anti-GBM Test Kit Requlatory Class: II Product Code: DBL 82 Dated: January 19, 1998 January 20, 1998 Received:

Dear Mr. Boteler:

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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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 [phone].

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 [phone]. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at [phone]. 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 [phone] or at [phone] or at its internet address "http://www.fda.gov/cdrh/dsmamain.html"

Sincerely yours,

Steven Putman

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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Page 1 of 1

K974169 510(k) Number: Not known

Device Name: Wielisa anti-GBM Test Kit

Indications For Use: The Wielisa anti-GBM Test Kit is an Enzyme Linked Immunosorbent Assay (ELISA) for the detection and semi-quantitation of IgG antibodies in human serum to GBM (glomerular basement membrane). The assay is used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of Goodpasture syndrome.

Peter E. Madson

(Division Sign-Off) (Division Sign-Oft)
Division of Clinical Laboratory Devices y 2741 69 510(k) Number

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use (Per 21 CFR 801.109)

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OR

Over-The Counter Use (Optional Format 1-2-96)