← Product Code [LLL](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LLL) · K964787

# MARDX ENA IGG IMMUNOSTRIPE TEST SYSTEM / MARDX ENA IGG MARSTRIPE TEST SYSTEM (K964787)

_Mardx Diagnostics, Inc. · LLL · Apr 8, 1997 · Immunology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LLL/K964787

## Device Facts

- **Applicant:** Mardx Diagnostics, Inc.
- **Product Code:** [LLL](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LLL.md)
- **Decision Date:** Apr 8, 1997
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 866.5100
- **Device Class:** Class 2
- **Review Panel:** Immunology

## Intended Use

The MarDx ENA IgG ImmunoStripe Test System is intended for use in testing human serum for the presence of human IgG to extractable nuclear antigens, as an aid in the diagnosis of autoimmune disease, such as systemic lupus erythematosus, Sjogren syndrome, scleroderma, and myositis.

## Device Story

Enzyme-linked immunosorbent assay (EIA) for detection of IgG antibodies to extractable nuclear antigens (SSA, SSB, Sm, RNP, Jo-1, Scl-70) in human serum; purified antigens immobilized on nitrocellulose strips; patient serum added to strip; if specific antibodies present, they bind to antigens; enzyme-labeled anti-human IgG conjugate added; substrate solution added; enzyme/antibody complex causes color precipitation at specific locations on strip; visual interpretation of color change indicates presence of specific antibodies; used in clinical laboratory settings; aids healthcare providers in diagnosing autoimmune conditions; provides qualitative diagnostic information.

## Clinical Evidence

Clinical study evaluated 264 human serum samples (139 normal, 125 autoimmune disease patients). Compared MarDx ENA IgG Immunostripe against INOVA EIA and MarDx 6-in-1 EIA. Combined sensitivity 95%, specificity 100%. Individual antigen sensitivity ranged from 89% (RNP) to 100% (Sm, Jo-1, Scl-70). Precision study (n=7 samples, 8 replicates across 3 assays) showed 100% precision. Cross-reactivity study (n=7 dsDNA positive samples) showed 0% cross-reactivity.

## Technological Characteristics

Enzyme-linked immunosorbent assay (EIA) using nitrocellulose solid phase support; purified antigens (SSA, SSB, Sm, RNP, Jo-1, Scl-70) immobilized on strip; enzyme-labeled anti-human IgG conjugate; colorimetric substrate precipitation; visual readout.

## Regulatory 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

- INOVA ENA EIA (SSA, SSB, Sm, RNP, Jo-1, Scl-70)
- MarDx ENA EIA 6 in 1 Test System

## Submission Summary (Full Text)

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>
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{0}

ATTACHMENT 1 - 510K Summary

APR - 8 1997

# 510(k) Summary of Safety and Effectiveness Information
## MarDx ENA IgG Immunostripe Test System

K964787

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

## Identification of Predicate Devices:

The MarDx ENA IgG Immunostripe Test System is substantially equivalent to the INOVA ENA EIA's for SSA, SSB, Sm, RNP, Jo-1, Scl-70 and the MarDx ENA EIA 6 in 1 Test System for the detection of immunoglobulin to SSA, SSB, Sm, RNP, Jo-1, Scl-70 in human serum.

## Description of New Device:

The MarDx ENA IgG Immunostripe Test System is an enzyme-linked immunosorbent assay (EIA) for the detection of IgG to extractable nuclear antigens in human serum.

## Statement of Intended Use:

The MarDx ENA IgG ImmunoStripe Test System is intended for use in testing human serum for the presence of human IgG to extractable nuclear antigens, as an aid in the diagnosis of autoimmune disease, such as systemic lupus erythematosus, Sjogren syndrome, scleroderma, and myositis.

## Technological Characteristics of the Device:

The MarDx ENA IgG Immunostripe Test System is an enzyme linked immunosorbent assay to detect IgG, to SSA, SSB, Sm, RNP, Jo-1, Scl-70. Purified antigens are individually attached to specific locations on a solid phase support, nitrocellulose. Diluted test sera is added to a well containing the Immunostripe strip. If the antibodies are present that recognize an antigen, they will bind to the antigen present on the strip. After incubation the nitrocellulose strip is washed to remove unbound antibody. An enzyme labeled antihuman IgG is added to each strip. If antibody is present the conjugate will bind to the antibody attached to the specific antigens. The strip is washed to remove unbound conjugate and a substrate solution is then added. If the enzyme/antibody complex is present, the substrate will undergo a precipitation and color change. After an incubation period, the reaction is stopped and the presence of precipitated substrate is visualized at specific locations on the strip. The presence of a colored precipitation at pre-determined locations on the Immunostripe strip is an indirect measurement of specific antibody for SSA, SSB, Sm, RNP, Jo-1, Scl-70 in the patient specimen.

## Description and Conclusions of the Clinical Studies.

The MarDx ENA IgG Immunostripe Test System is substantially equivalent to the INOVA ENA EIA's for SSA, SSB, Sm, RNP, Jo-1, Scl-70 and the MarDx ENA EIA 6 in 1 Test System for the detection of immunoglobulin to SSA, SSB, Sm, RNP, Jo-1, Scl-70 in human serum. Equivalence is demonstrated by the following comparative results:

{1}

Two hundred and sixty four sera were tested by EIA (INOVA ELISA for ENA antibodies), and the MarDx 6 in 1 ENA EIA, to determine the relative sensitivity and specificity of the MarDx ENA IgG Immunostripe test kit. One hundred and thirty-nine of the sera were from normal individuals which should not have antibodies to ENA antigens. One hundred and twenty five sera were from patients thought to have autoimmune disease and submitted as blind specimens for ENA antigen detection. The MarDx and INOVA assays were performed by the R&D laboratory at MarDx following manufacturer's package insert. Assay sensitivity ranged from 89 to 100%, specificity was 100%. The raw data from the study is prepared in Attachment 5. The data is summarized in Tables 1-11.

Table 1
Specificity of the MarDx ENA IgG Immunostripe Test System relative to the INOVA EIA Test Systems

|   |  | INOVA EIA |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 0 | 0 | 0  |
|  Immunostripe |  |  |  |   |
|   | Negative | 0 | 40 | 40  |
|  Total |  | 0 | 40 | 40  |

Specificity (40/40) = 100%

Table 2
Specificity of the MarDx ENA IgG Immunostripe Test System relative to the MarDx 6 in 1 ENA EIA Test System

|   |  | MarDx 6 in 1 ENA EIA |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 0 | 0 | 0  |
|  Immunostripe |  |  |  |   |
|   | Negative | 0 | 139 | 139  |
|  Total |  | 0 | 139 | 139  |

Specificity (139/139) = 100%

Table 3
Sensitivity of the MarDx ENA IgG Immunostripe Test System relative to the INOVA SSA EIA Test System

|  Antigen: SSA |  | INOVA SSA EIA |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 35 | 0 | 35  |
|  Immunostripe |  |  |  |   |
|   | Negative | 2 | 0 | 2  |
|  Total |  | 37 | 0 | 37  |

SSA Sensitivity (35/37) = 95%

{2}

Table 4
Sensitivity of the MarDx ENA IgG Immunostripe Test System
relative to the INOVA SSB EIA Test System

|  Antigen: SSB |  | INOVA SSB EIA |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 16 | 0 | 16  |
|  Immunostripe |  |  |  |   |
|   | Negative | 1 | 0 | 1  |
|  Total |  | 17 | 0 | 17  |

SSB Sensitivity (16/17) = 94%

Table 5
Sensitivity of the MarDx ENA IgG Immunostripe Test System
relative to the INOVA Sm EIA Test System

|  Antigen: Sm |  | INOVA Sm EIA |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 20 | 1 | 21  |
|  Immunostripe |  |  |  |   |
|   | Negative | 0 | 0 | 0  |
|  Total |  | 20 | 1 | 21  |

Sm Sensitivity (20/20) = 100%

Table 6
Sensitivity of the MarDx ENA IgG Immunostripe Test System
relative to the INOVA RNP EIA Test System

|  Antigen: RNP |  | INOVA RNP EIA |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 33 | 0 | 33  |
|  Immunostripe |  |  |  |   |
|   | Negative | 4 | 0 | 4  |
|  Total |  | 37 | 0 | 37  |

RNP Sensitivity (33/37) = 89%

{3}

Table 7
Sensitivity of the MarDx ENA IgG Immunostripe Test System
relative to the INOVA Jo-1 EIA Test System

|  Antigen: Jo-1 |  | INOVA Jo-1 EIA |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 2 | 0 | 2  |
|  Immunostripe |  |  |  |   |
|   | Negative | 0 | 0 | 0  |
|  Total |  | 2 | 0 | 2  |

Jo-1 Sensitivity (2/2)= 100%

Table 8
Sensitivity of the MarDx ENA IgG Immunostripe Test System
relative to the INOVA Scl-70 EIA Test System

|  Antigen: Scl-70 |  | INOVA Scl-70 |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 7 | 0 | 7  |
|  Immunostripe |  |  |  |   |
|   | Negative | 0 | 0 | 0  |
|  Total |  | 7 | 0 | 7  |

Scl-70 Sensitivity (7/7)= 100%

Table 9
INOVA SUMMARY
Sensitivity of the MarDx ENA IgG Immunostripe Test System
relative to the Six Combined Results from the INOVA ENA EIA Test Systems

|  Combined |  | INOVA ENA EIA |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 113 | 0 | 113  |
|  Immunostripe |  |  |  |   |
|   | Negative | 7 | 0 | 7  |
|  Total |  | 120 | 0 | 120  |

Sensitivity (113/120) = 94%

{4}

Table 10
Sensitivity of the MarDx ENA IgG Immunostripe Test System relative to the MarDx 6 in 1 ENA EIA Test System

|   |  | MarDx ENA EIA |   |   |
| --- | --- | --- | --- | --- |
|   |  | Positive | Negative | Total  |
|  MarDx | Positive | 67 | 0 | 67  |
|  Immunostripe |  |  |  |   |
|   | Negative | 2 | 0 | 2  |
|  Total |  | 69 | 0 | 69  |

Sensitivity (67/69) = 97%

Table 11
Summary Table For All Data

|  MarDx |  | Reference Manufacturer | Number of Specimens | Reference | Sensitivity | Specificity  |
| --- | --- | --- | --- | --- | --- | --- |
|  Immunostripe | vs | INOVA | 35/37 | SSA | 95% | NA  |
|  Immunostripe | vs | INOVA | 16/17 | SSB | 94% | NA  |
|  Immunostripe | vs | INOVA | 20/20 | Sm | 100% | NA  |
|  Immunostripe | vs | INOVA | 33/37 | RNP | 89% | NA  |
|  Immunostripe | vs | INOVA | 2/2 | Jo-1 | 100% | NA  |
|  Immunostripe | vs | INOVA | 7/7 | Scl-70 | 100% | NA  |
|  Immunostripe | vs | INOVA | 40/40 | Normals | NA | 100%  |
|  Immunostripe | vs | MarDx | 67/69 | 6 in 1 | 97% | NA  |
|  Immunostripe | vs | MarDx | 139/139 | Normals | NA | 100%  |
|  Immunostripe | Combined Sensitivity and Specificity |   |   |   | 95% | 100%  |

{5}

# Precision Study

The precision data is presented in Table 10 for 7 sera (Jo-1, 3 sera) assayed 8 times each on three different assays. The data indicates that the MarDx ENA Immunostripe has a high degree of precision both within and between assays.

Table 12

|  Sample |   | Assay 1 |   | Assay 2 |   | Assay 3  |   |
| --- | --- | --- | --- | --- | --- | --- | --- |
|   |  | Ratio | Percent |  |  |  |   |
|  1 | SSA | 7/7 | 100% | 7/7 | 100% | 7/7 | 100%  |
|  2 | SSB | 7/7 | 100% | 7/7 | 100% | 7/7 | 100%  |
|  3 | Sm | 7/7 | 100% | 7/7 | 100% | 7/7 | 100%  |
|  4 | RNP | 7/7 | 100% | 7/7 | 100% | 7/7 | 100%  |
|  5 | Jo-1 | 3/3 | 100% | 3/3 | 100% | 3/3 | 100%  |
|  6 | Scl-70 | 7/7 | 100% | 7/7 | 100% | 7/7 | 100%  |
|  7 | Normal | 7/7 | 100% | 7/7 | 100% | 7/7 | 100%  |
|  TOTALS |   | 45/45 | 100% | 45/45 | 100% | 45/45 | 100%  |

Precision = 100%

# Cross-Reactivity Study

The cross-reactivity data is presented in Table 11 for 7 sera containing dsDNA antibodies. The data indicates that the MarDx ENA Immunostripe does not cross-react with dsDNA.

Table 13

|  Sample | Result  |
| --- | --- |
|  1 | Neg  |
|  2 | Neg  |
|  3 | Neg  |
|  4 | Neg  |
|  5 | Neg  |
|  6 | Neg  |
|  7 | Neg  |

Cross Reactivity to dsDNA = 0%

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**Source:** [https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LLL/K964787](https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LLL/K964787)

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