← Product Code [LSW](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LSW) · K060380

# FIDIS DSDNA (K060380)

_Biomedical Diagnostics (Bmd) SA · LSW · May 2, 2006 · Immunology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LSW/K060380

## Device Facts

- **Applicant:** Biomedical Diagnostics (Bmd) SA
- **Product Code:** [LSW](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LSW.md)
- **Decision Date:** May 2, 2006
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 866.5100
- **Device Class:** Class 2
- **Review Panel:** Immunology

## Intended Use

The FIDIS™ dsDNA kit is a semi-quantitative homogeneous fluorescent-based microparticles immunoassay using flow cytometry readings. It is designed for the detection of antibodies directed against double stranded DNA. The presence of these antibodies can be used in conjunction with clinical findings to aid in the diagnosis of SLE. The FIDIS™ dsDNA kit is to be used on serum only and used on the FIDIS™ Analyzer, MLX Booster software and washer.

## Device Story

FIDIS™ dsDNA is a semi-quantitative fluorescent immunoassay for detecting anti-dsDNA antibodies. Input: patient serum samples mixed with dsDNA-coupled color-coded microspheres in 96-well plates. Process: patient antibodies bind to bead-immobilized antigen; unbound material washed; phycoerythrin-conjugated anti-human IgG added to form antigen/antibody complex. Output: fluorescence intensity measured via flow cytometry. System includes FIDIS analyzer, XYP platform for automatic sampling, and MLX-BOOSTER software. Used in clinical laboratories by trained personnel. Software identifies microsphere color codes to associate with specific antigens and quantifies fluorescence to calculate biological units. Results aid clinicians in diagnosing SLE.

## Clinical Evidence

No clinical prospective or retrospective studies were performed. Evidence consists of bench testing, including precision/reproducibility (within-run and between-run CVs reported), analytical specificity (cross-reactivity testing with 35 samples), and a method comparison study against the predicate device (N=400) showing 96.33% positive agreement and 95.53% negative agreement. Cut-off establishment was performed using 85 samples (50 normal, 35 with potential interference).

## Technological Characteristics

Multiplex bead-based flow cytometric immunoassay. Uses color-coded microspheres coupled with recombinant dsDNA. Detection via phycoerythrin-labeled anti-human IgG conjugate. Instrumentation: Luminex 100 flow cytometer with red (classification) and green (quantification) lasers. Digital signal processing hardware and software. Serum matrix only. Prescription use.

## 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

- Varelisa® dsDNA Antibodies (k950031)

## Submission Summary (Full Text)

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>
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

A. 510(k) Number:
k060380

B. Purpose for Submission:
This is a new device.

C. Measurands:
Anti-DNA Antibodies

D. Type of Test:
Multiplex bead-based flow cytometric immunoassay

E. Applicant:
Biomedical Diagnostics (bmd) S.A.

F. Proprietary and Established Names:
FIDIS™ dsDNA

G. Regulatory Information:
1. Regulation section:
21CFR§ 866.5100, Antinuclear Antibody Immunological Test System
2. Classification:
Class II
3. Product code:
LSW, Anti-DNA Antibody, Antigen and Control
4. Panel:
Immunology (82)

H. Intended Use:
1. Intended use(s):
The FIDIS™ dsDNA kit is a semi-quantitative homogeneous fluorescent-based microparticles immunoassay using flow cytometry readings. It is designed for the detection of antibodies directed against double stranded DNA.
1. Indication(s) for use:
The presence of these antibodies can be used in conjunction with clinical findings to aid in the diagnosis of SLE.
The FIDIS™ dsDNA kit is to be used on serum only and used on the FIDIS™ Analyzer, MLX Booster software and washer.
3. Special conditions for use statement(s):
This device is for prescription use only.
4. Special instrument requirements:
FIDIS™ Instrument (Luminex 100™plus FIDIS™ MLX-Booster Software). CARIS™ system (diluting/dispensing device), optional.

I. Device Description:
The device consists of the following: color-coded sets of microspheres coupled with dsDNA (ready-to-use); calibrator (ready to use); positive control (to be diluted); negative control (to be diluted); goat anti-human IgG coupled to phycoerythrin (to be diluted) and 10x concentrated PBS-Tween (to be diluted

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with distilled water)

## J. Substantial Equivalence Information:

1. Predicate device name(s): Varelisa® dsDNA Antibodies
2. Predicate 510(k) number(s): k950031
3. Comparison with predicate:

|  Similarities  |   |   |
| --- | --- | --- |
|  Item | Device | Predicate  |
|   | FIDISTM dsDNA kit | Varelisa® dsDNA  |
|  Intended Use | Determination of IgG antibodies against dsDNA | Same  |
|  Sample type | Serum | Same  |
|  Type of test | Semi-quantitative | Same  |
|  Antigen | Recombinant dsDNA | Same  |
|  Differences  |   |   |
| --- | --- | --- |
|  Item | Device | Predicate  |
|  Assay type | Flow Cytometer based | ELISA  |
|  Assay Format | Multiplexed | Individual assays  |
|  Sample Dilution | 1:200 | 1:101  |
|  Substrate solution | None | TMB  |
|  Instrument | Luminometer (Luminex v. 100) | Spectrophotometer  |
|  Detection method | Fluorescence | Colorimetric  |
|  Conjugate | Phycoerythrin | HR peroxidase  |
|  Solid Phase Capture | Color-coded microspheres | Microwells  |

## K. Standard/Guidance Document Referenced (if applicable):

None referenced.

## L. Test Principle:

FIDISTM dsDNA is based on the use of distinct uniform size color-coded microspheres and a benchtop flow cytometer interfaced to digital signal processing hardware and software. A red diode laser beam in the flow cytometer classifies each set of microspheres on the basis of its unique fluorescence intensity (red to orange) thus identifying which analyte is being tested. At the same time, a green laser beam illuminates the external second molecule fluorescence to quantify the reaction related to the specific analyte.

The test is performed in a 96 well blank microplate with a filtering membrane at the bottom of the wells. In the first step, the sample is distributed in each well containing the microspheres covalently coupled to dsDNA. If this sample contains the suspected antibodies, these antibodies bind to the antigen. After incubation, a wash step using a filtration process removes the unbound antibodies.

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A phycoerythrin labeled anti-human IgG will bind to the captured antibodies. The reaction is then directly measured by the flow cytometer, which categorizes each set of microspheres according to its fluorescence color while simultaneously measuring the average fluorescence emitted by the conjugate. A calibration system permits the determination of the titer of each sample by interpolation for each antigenic specificity.

## M. Performance Characteristics (if/when applicable):

### 1. Analytical performance:

#### a. Precision/Reproducibility:

To evaluate intra-assay and inter assay reproducibility, nine samples were analyzed on the FIDISTM dsDNA. For within-run, the nine samples were assayed 10 times in one run and for between-run; the nine samples were assayed 4 times per run for 6 runs. Results were as follows:

|   | Within-run |   | Between-run  |   |
| --- | --- | --- | --- | --- |
|  Antigen | Mean value | %CV | Mean Value | %CV  |
|  dsDNA | 23 | 3 | 24 | 6  |
|   |  45 | 3 | 51 | 9  |
|   |  46 | 3.8 | 53 | 8.3  |
|   |  70 | 4.3 | 69 | 4.3  |
|   |  84 | 12.2 | 90 | 11.3  |
|   |  138 | 3.9 | 140 | 4.2  |
|   |  162 | 4.8 | 199 | 7.4  |
|   |  519 | 2.8 | 524 | 5.6  |
|   |  579 | 7.6 | 709 | 11.8  |

Precision of the assay using the optional automated CARIS system was assessed. For within-run, five samples were assayed 10 times in one run and for between-run; five samples were assayed 4 times per run for 6 runs. Results were as follows:

|   | Within-run |   | Between-run  |   |
| --- | --- | --- | --- | --- |
|  Antigen | Mean value | %CV | Mean Value | %CV  |
|  dsDNA | 41 | 6.8 | 41 | 6.2  |
|   |  70 | 4.5 | 67.7 | 7.2  |
|   |  80 | 7.0 | 70.8 | 11.2  |
|   |  94 | 8.9 | 98.3 | 10.4  |
|   |  894 | 5.3 | 871.5 | 5.2  |

#### b. Linearity/assay reportable range:

Linearity is not claimed for this assay.

#### c. Traceability, Stability, Expected values (controls, calibrators, or methods):

The dsDNA values in the calibrator are established using the WHO International Standard for Anti-double stranded DNA (dsDNA), human code: WO/80. The WHO WO/80 standard is lyophilized powder and is reconstituted to a concentration of 200 IU/mL. Information leaflet from WHO (First International Standard for Antibodies for Anti Double-stranded DNA (dsDNA)) was provided.

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d. Detection limit:

Not applicable

e. Analytical specificity:

Interfering substances

To evaluate the system for potential cross reactivity to other antibodies and interference from blood components, 35 samples were tested. High level of complement proteins were used but the specific kind of complement was not provided. A statement to avoid the use of abnormal concentration of these samples was added to the Limitations of the Procedure. The following results were obtained.

|  Samples | No of samples positive for dsDNA  |
| --- | --- |
|  Cryoglobulinemia N=5 | 0  |
|  Complement N=10 | 2  |
|  Hypergammaglobulinemia N=1 | 0  |
|  IgG monoclonal immunoglobulins N=3 | 0  |
|  IgM monoclonal immunoglobulins N=7 | 0  |
|  Rheumatoid Factor N=2 | 0  |
|  Plasma (sodium citrate)N =5 | 0  |
|  Hemolyzed sera N=2 | 0  |

f. Assay cut-off:

Eighty five (85) samples including 50 normal blood donor samples and 35 samples with potential biological interferences (see analytical specificity) were run to establish the cut-offs for the assays. The following results were obtained:

|  Percentile of the Distribution values | 30 IU/mL | 40 IU/mL  |
| --- | --- | --- |
|  dsDNA | 94.1% (80/85) | 95.3% (81/85)  |

Between these thresholds, results are considered equivocal or borderline.

2. Comparison studies:

a. Method comparison with predicate device:

The table below shows the comparison of serum samples  $(N = 400)$  that were tested with the FIDISTM dsDNA and the predicate device. No information about age, gender, and clinical status was provided.

- 109 positive samples for one or more parameters related to systemic autoimmune diseases
291 negative samples
- All borderline results with the two devices were considered negative.

|   | Varelisa dsDNA  |   |   |
| --- | --- | --- | --- |
|   |   |  Pos | Neg  |
|  FIDIS dsDNA | Pos | 105 | 13  |
|   |  Neg | 4 | 278  |

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Positive % agreement: 96.33% (95% CI: 92.8 - 99.9%)
Negative % agreement: 95.53% (95% CI: 93.2 - 97.9%)
Overall % agreement: 95.75% (95% CI: 93.8 - 97.7%)

A study was performed to compare the manual FIDIS™ dsDNA and the optional automated diluting/dispensing device CARIS™. The comparison was performed on 151 samples. The following results were obtained:

|  dsDNA | Manual FIDIS  |   |   |
| --- | --- | --- | --- |
|   |   |  Pos | Neg  |
|  CARIS
FIDIS | Pos | 58 | 3  |
|   |  Neg | 0 | 90  |

Positive % agreement: 100%
Negative % agreement: 96.8%
Overall % agreement: 98%
The three discrepant samples with the CARIS FIDIS were false positives for dsDNA.

b. Matrix comparison:
Serum is the only recommended matrix.

3. Clinical studies:
a. Clinical Sensitivity:
Not applicable
b. Clinical specificity:
Not applicable
c. Other clinical supportive data (when a. and b. are not applicable):
Not applicable

4. Clinical cut-off:
Not applicable

5. Expected values/Reference range:
Expected values in the normal population should be negative.

N. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

O. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.

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**Source:** [https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LSW/K060380](https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/LSW/K060380)

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