DIAMEDIX IS-ANTI-DSDNA TEST SYSTEM

K994424 · Diamedix Corp. · LRM · Feb 18, 2000 · Immunology

Device Facts

• Record ID: K994424
• Device Name: DIAMEDIX IS-ANTI-DSDNA TEST SYSTEM
• Applicant: Diamedix Corp.
• Product Code: LRM · Immunology
• Decision Date: Feb 18, 2000
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.5100
• Device Class: Class 2

Intended Use

The Diamedix Is-anti-dsDNA an Enzyme Immunoassay (EIA) for the quantitative detection of IgG antibodies to double-stranded (ds) DNA in human serum as an aid in the diagnosis of systemic lupus erythematosus (SLE). These reagents can be used either manually or in conjunction with the MAGO® Plus Automated EIA Processor.

Device Story

The Is-anti-dsDNA Test System is an enzyme-linked immunosorbent assay (ELISA) used to detect and quantify IgG antibodies to dsDNA in human serum. Purified plasmid DNA is immobilized on microtiter wells; patient serum is added; if anti-dsDNA antibodies are present, they bind to the antigen. After incubation and washing, an enzyme-labeled anti-human immunoglobulin conjugate is added, followed by a substrate solution. The resulting color intensity is measured photometrically, providing an indirect measure of antibody concentration. The test is performed either manually or using the MAGO Plus Automated EIA Processor in a clinical laboratory setting. Results assist clinicians in the diagnosis of systemic lupus erythematosus (SLE).

Clinical Evidence

Performance evaluated using 413 samples (200 normal, 209 clinical patients with SLE or autoimmune disease, 4 unknown). Relative sensitivity and specificity compared to a commercial ELISA with WHO traceability. Manual method 6-point calibration showed 96.3% sensitivity and 96.0% specificity. Clinical sensitivity for SLE patients was 84.8% (95% CI: 73.9-92.5%) and clinical specificity for normal donors was 100.0% (95% CI: 98.1-100.0%). Precision studies (intra- and inter-assay) performed manually and on MAGO Plus showed acceptable CVs.

Technological Characteristics

Enzyme-linked immunosorbent assay (ELISA) using purified plasmid DNA immobilized on microtiter wells. Employs enzyme-labeled anti-human immunoglobulin conjugate and substrate for photometric detection. Supports manual or automated (MAGO Plus) processing. Calibration via 6-point or single-point methods. Quantitative output in IU/ml.

Indications for Use

Indicated for the quantitative detection of IgG antibodies to dsDNA in human serum as an aid in the diagnosis of systemic lupus erythematosus (SLE).

Regulatory Classification

Identification

An antinuclear antibody immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoimmune antibodies in serum, other body fluids, and tissues that react with cellular nuclear constituents (molecules present in the nucleus of a cell, such as ribonucleic acid, deoxyribonucleic acid, or nuclear proteins). The measurements aid in the diagnosis of systemic lupus erythematosus (a multisystem autoimmune disease in which antibodies attack the victim's own tissues), hepatitis (a liver disease), rheumatoid arthritis, Sjögren's syndrome (arthritis with inflammation of the eye, eyelid, and salivary glands), and systemic sclerosis (chronic hardening and shrinking of many body tissues).

Predicate Devices

• Enzyme Immunoassay Anti-dsDNA Test

Submission Summary (Full Text)

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# FEB 1 8 2000

## 510(k) Summary of Safety and Effectiveness

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.

The assigned 510(k) number is: K994424

#### Applicant Information:

| Date Prepared: | December 29, 1999 |
|----------------|-----------------------------------------|
| Name: | Diamedix Corporation |
| Address: | 2140 N. Miami Avenue<br>Miami, FL 33127 |

| Contact Person: | Dr. Lynne Stirling |
|-----------------|--------------------|
| Phone Number: | 305-324-2354 |
| Fax Number: | 305-324-2585 |

#### Device Information:

| Trade Name: | Is-anti-dsDNA Test System |
|----------------------|---------------------------|
| Common Name: | Anti-DNA EIA Test |
| Classification Name: | Anti-DNA Antibody |

#### Equivalent Device:

Enzyme Immunoassay Anti-dsDNA Test

Device Description: The Is-anti-dsDNA Test Kit System is an enzyme-linked immunosorbent assay (ELISA) for the detection and quantitation of IgG antibodies to DNA in human serum.

Intended Use: The assay is intended for use in detecting IgG antibodies to dsDNA in a single human serum sample. The results of the assay are to be used as an aid in the diagnosis of SLE.

### Principle of the Procedure:

The Is-anti-dsDNA Test System is an enzyme-linked immunosorbent assay to detect IgG antibdies to dsDNA in human serum. Purified plasmid DNA is attached to a solid phase microtiter well. Diluted test sera are added to each well. If antibodies which recognize the DNA antigen are present in the patient sample they will bind to the antigen in the well. After incubation, the wells are washed to remove unbound antibody. An enzyme labeled antihuman immunoglobulin (conjugate) is added to each test well. If antibody is present the enzyme-linked antibody will bind to it. After incubation, the wells are washed to remove unbound conjugate. A substrate solution is then added to each well. If enzyme is present from prior step, the reaction is stopped and the color intensity is measured photometrically producing an indirect measure of the specific antibody present in the patient sample.

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### SUMMARY OF SAFETY AND EFFECTIVENESS

### Performance Characteristics

# A. Comparison Studies : Relative Sensitivity and Specificity

The Diamedix Is-anti-dsDNA Test Kit was evaluated relative to another commercially available antidsDNA ELISA test with traceability to the WHO Standard. A total of 413 samples were tested by both methods. These samples were comprised of two hundred sera from normal blood donors, two hundred and nine sera from clinical patients with either a diagnosis of SLE or another autoimmune disease and four sera from patients whose status was unknown. Performance is summarized in TABLE 1 for both 6-Point and Single Point Calibration using the manual method of testing. Similar results were obtained using the MAGO Plus automated testing method.

| | and been been been been been been and en de sent of the bestille beginnen with and the bestille of the bestille be | | | | | |
|----------------------|--------------------------------------------------------------------------------------------------------------------|------|-----------|--------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------|
| | 6-Point Calibration | | | Single Point Calibration | | |
| | # of sera | 90 | 95% CI | # of sera | % | 95% CI |
| Relative Sensitivity | 104/108 | 96.3 | 90.8-99.0 | 111/112 | 99.1 | 95.1-100.0 |
| Relative Specificity | 264/275 | 96.0 | 93.0-98.0 | 251/271 | 92.6 | 88.8-95.4 |
| Overall Agreement* | 368/383 | 96.1 | 93.6-97.8 | 362/383 | તેવ વિત્તર જેવી સાથે છે. આ ગામનાં પ્રાથમિક શાળા, પંચાયતઘર, આંગણવાડી તેમ જ દૂધની ડેરી જેવી સવલતો પ્રાપ્ય થયેલી છે. આ ગામનાં પ્રાથમિક શાળા, પંચાયતઘર, આંગણવાડી તેમ જ દૂધની ડેરી | 91.7-96.6 |

| TABLE<br>4<br>P<br>1 | - |
|----------------------|---|
|----------------------|---|

* Equivocal and ONS samples were excluded from calculations

NOTE : Please be advised that 'relative' refers to the assay's results to that of a similar assay. There was not an attempt to correlate the assay's results with disease presence or absence. No judgment can be made on the comparison's accuracy to predict disease.

### B. Clinical Sensitivity and Specificity Using Characterized Sera

Clinical sensitivity and specificity was assessed by evaluating the results from each patient group . The groups consisted of 200 normal samples, 70 sera from patients with a diagnosis of SLE and 138 sera from patients with suspected autoimmune disease. The results presented in TABLE 2 were obtained manually using the 6-Point calibration method.

| Patient Group: | Positive | Equivocal* | Negative | Total |
|-----------------------|--------------------|------------|---------------|------------|
| Normals | 0 | 3 | 197 | 200 |
| SLE | 56 | 4 | 10 | 70 |
| Autoimmune Disease | 63 | 5 | 70 | 138 |
| Clinical Specificity: | | | <b>95% CI</b> | |
| Normals | = 197/197 = 100.0% | | | 98.1-100.0 |
| Clinical Sensitivity: | | | <b>95% CI</b> | |
| SLE patients | = 56/66 = 84.8% | | | 73.9-92.5 |

73.9-92.5

TARI F 2

Autoimmune disease patients = 63/133 = 47.4% 38.9-55.9

* Equivocal results were excluded from calculations

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### C. Precision

The precision of the Is-anti-dsDNA Test Kit when performed either manually or on the MAGO Plus Automated EIA Processor using the 6-Point calibration method was determined by assaying six sera and the kit positive and negative controls in triplicate in two runs per days. TABLES 3 and 4 show the intra-and interassay precision obtained. Comparable CVs for positive samples were also obtained when precision testing was performed using the Single Point calibration method (data on file).

| SERUM | INTRA-ASSAY DAY 1 | | | INTRA-ASSAY DAY 2 | | | INTRA-ASSAY DAY 3 | | | INTERASSAY | | |
|----------|-------------------|------|------|-------------------|------|------|-------------------|------|-----|---------------|------|------|
| | MEAN<br>IU/ml | SD | CV% | MEAN<br>IU/ml | SD | CV% | MEAN<br>IU/ml | SD | CV% | MEAN<br>IU/ml | SD | CV% |
| A (NEG) | 0.0 | 0.00 | N/A | 0.0 | 0.00 | N/A | 0.0 | 0.00 | N/A | 0.0 | 0.00 | N/A |
| B (NEG) | 0.0 | 0.00 | N/A | 0.0 | 0.00 | N/A | 0.0 | 0.00 | N/A | 0.0 | 0.00 | N/A |
| C (POS) | 49.3 | 5.17 | 10.5 | 48.5 | 7.12 | 14.7 | 45.1 | 0.95 | 2.1 | 47.6 | 5.17 | 10.9 |
| D (POS) | 68.5 | 6.88 | 10.0 | 62.3 | 5.45 | 8.8 | 66.9 | 1.95 | 2.9 | 65.9 | 5.59 | 8.5 |
| E (POS) | 96.6 | 5.89 | 6.1 | 90.5 | 8.16 | 9.0 | 79.2 | 4.51 | 5.7 | 88.7 | 9.53 | 10.7 |
| F (POS) | 152.4 | 4.06 | 2.7 | 156.9 | 8.61 | 5.5 | 150.3 | 1.59 | 1.1 | 153.2 | 5.95 | 3.9 |
| POS CTRL | 69.1 | 5.57 | 8.1 | 70.3 | 2.99 | 4.3 | 66.4 | 2.20 | 3.3 | 68.6 | 4.00 | 5.8 |
| NEG CTRL | 0.0 | 0.00 | N/A | 0.0 | 0.00 | N/A | 0.0 | 0.00 | N/A | 0.0 | 0.00 | N/A |

TABLE 3: Intra-Assay and Interassay Precision-Manual Testing

TABLE 4 : Intra-Assay and Interassay Precision - MAGO Plus Testing

| SERUM | INTRA-ASSAY DAY 1 | | | INTRA-ASSAY DAY 2 | | | INTRA-ASSAY DAY 3 | | | INTERASSAY | | |
|----------|-------------------|------|------|-------------------|-------|-----|-------------------|-------|-----|---------------|-------|------|
| | MEAN<br>IU/ml | SD | CV% | MEAN<br>IU/ml | SD | CV% | MEAN<br>IU/ml | SD | CV% | MEAN<br>IU/ml | SD | CV% |
| A (NEG) | 0.0 | 0.00 | 0.0 | 0.0 | 0.00 | 0.0 | 0.0 | 0.00 | 0.0 | 0.0 | 0.00 | 0.0 |
| B (NEG) | 0.0 | 0.00 | 0.0 | 2.1 | 2.90 | 0.0 | 0.0 | 0.00 | 0.0 | 0.0 | 0.00 | 0.0 |
| C (POS) | 52.9 | 3.55 | 6.7 | 51.3 | 2.80 | 5.5 | 52.6 | 3.26 | 6.2 | 52.3 | 3.11 | 5.9 |
| D (POS) | 76.0 | 5.02 | 6.6 | 76.8 | 3.14 | 4.1 | 72.9 | 5.19 | 7.1 | 75.2 | 4.61 | 6.1 |
| E (POS) | 80.0 | 9.54 | 11.9 | 81.6 | 6.58 | 8.1 | 89.7 | 7.36 | 8.2 | 83.8 | 8.63 | 10.3 |
| F (POS) | 164.6 | 7.49 | 4.6 | 158.1 | 11.40 | 7.2 | 162.0 | 11.40 | 7.0 | 161.6 | 10.00 | 6.2 |
| POS CTRL | 76.5 | 2.28 | 3.0 | 75.6 | 2.04 | 2.7 | 74.2 | 3.08 | 4.1 | 75.4 | 2.54 | 3.4 |
| NEG CTRL | 0.0 | 0.00 | 0.0 | 0.0 | 0.00 | 0.0 | 0.0 | 0.00 | 0.0 | 0.0 | 0.00 | 0.0 |

#### D. Linearity

The dose response curve for the Is-anti-dsDNA test kit is sufficiently linear to allow for the use of either 6-Point or Single Point calibration systems. This linearity is illustrated in FIGURES 1 and 2. These figures depict samples that have been serially diluted in Sample Dilution tested and results determined using either calculation method. The samples selected were the WHO Reference preparation, the kit 200 IU/ml Standard and the in-house reference 200 IU/ml Standard. Recovered IU/ml values for each dilution were determined using either the 6-Point (FIGURE 1) or Single Point (FIGURE 2) calibration methods. The linearity data shown was obtained using the manual method of testing. Similar results were obtained using the MAGO Plus automated method.

Image /page/2/Figure/8 description: The image contains two figures, labeled as FIGURE 1 and FIGURE 2. FIGURE 1 shows a graph of Kit Standards (IU/ml) on the x-axis and Recovered Values (IU/ml) on the y-axis, with values ranging from 0 to 300. FIGURE 2 shows a graph of DILUTION on the x-axis and Recovered Values (IU/ml) on the y-axis, with dilution values ranging from 0.0 to 1.0. Both figures plot three different lines: Kit 200 IU/ml STD, In-house Ref STD, and WHO Ref, showing the relationship between the x and y axis for each of the three lines.

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Image /page/3/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" arranged around the perimeter. Inside the circle is a stylized image of a caduceus, which is a symbol often associated with medicine and healthcare. The caduceus in the logo is depicted with a staff and a serpent winding around it.

FEB 1 8 2000

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Lynne Stirling, Ph.D. Vice President, Regulatory Affairs Diamedix® Corporation 2140 North Miami Avenue Miami, Florida 33127

Re: K994424 Trade Name: Is-anti-dsDNA Test System Regulatory Class: II Product Code: LRM Dated: December 29, 1999 Received: December 30, 1999

Dear Dr. Stirling:

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

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" (21CFR 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 [phone] or at its internet address "http://www.fda.gov/cdrh/dsma/dsmamain.html".

Sincerely yours,

Steven Butman

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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# Appendix G. Indications for Use Statement

# INDICATIONS FOR USE STATEMENT

510(K) NUMBER : K994434

# DEVICE NAME : Is-anti-dsDNA Test System

Indications for Use :The Diamedix Is-anti-dsDNA an Enzyme Immunoassay (EIA) for the quantitative detection of IgG antibodies to double-stranded (ds) DNA in human serum as an aid in the diagnosis of systemic lupus erythematosus (SLE). These reagents can be used either manually or in conjunction with the MAGO® Plus Automated EIA Processor.

Peter E. Magni

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use V (Per 21 CFR 801.109)

OR

Over-The-Counter Use

(Optional Format 1-2-96)