HEMAGEN RHEUMATOID FACTOR KIT (EIA METHOD)

K962836 · Hemagen Diagnostics, Inc. · DHR · Sep 12, 1996 · Immunology

Device Facts

• Record ID: K962836
• Device Name: HEMAGEN RHEUMATOID FACTOR KIT (EIA METHOD)
• Applicant: Hemagen Diagnostics, Inc.
• Product Code: DHR · Immunology
• Decision Date: Sep 12, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.5775
• Device Class: Class 2

Indications for Use

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of circulating IgM rheumatoid factor. When used according to instructions, the kit is useful in establishing the presence of rheumatoid factor and as an aid in the diagnosis and management of rheumatic diseases.

Device Story

Hemagen Rheumatoid Factor Kit is an ELISA-based diagnostic test for detecting IgM rheumatoid factor in human serum or plasma. The device uses microwell plates coated with purified IgG; patient samples are incubated, allowing IgM rheumatoid factor to bind to the immobilized IgG. A secondary HRP-conjugated antibody binds to the patient's IgM; subsequent addition of substrate causes a color change proportional to the amount of bound rheumatoid factor. The color intensity is measured using an EIA plate reader. The test is performed in a clinical laboratory setting by trained personnel. Results are used by clinicians to assist in the diagnosis and management of rheumatic diseases. The device provides quantitative or semi-quantitative assessment of rheumatoid factor levels, aiding in clinical decision-making regarding disease status.

Clinical Evidence

Bench testing only. Precision studies (inter-assay and intra-assay) performed on 8 samples. Comparison testing against predicate device (N=106) showed 94.8% relative sensitivity and 93.1% relative specificity. Normal donor study (N=82) showed high concordance. Interference testing confirmed no significant effect from hemoglobin (≤ 500 mg/dL), lipids (≤ 3000 mg/dL), or bilirubin (≤ 20 mg/dL). Prozone effect testing confirmed high-titer samples yield appropriately high results.

Technological Characteristics

ELISA-based immunoassay. Components: IgG-coated microwell plates, HRP-conjugated secondary antibody, colorimetric substrate. Measurement: Optical density via EIA plate reader. Analyte: IgM rheumatoid factor. Sample types: Human serum and plasma. Calibration: Traceable to WHO International Reference Preparation of Rheumatoid Arthritis Serum.

Indications for Use

Indicated for the detection and measurement of IgM rheumatoid factor in human serum and plasma to aid in the diagnosis and management of rheumatic diseases in patients suspected of having such conditions.

Regulatory Classification

Identification

A rheumatoid factor immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the rheumatoid factor (antibodies to immunoglobulins) in serum, other body fluids, and tissues. Measurement of rheumatoid factor may aid in the diagnosis of rheumatoid arthritis.

Predicate Devices

• Hemagen RF Kit (K855221/A)

Submission Summary (Full Text)

{0}

SEP 12 1996
PAGE 1

510(k) Summary K962836

1. Submitter's Name/Contact Person

Joseph M. Califano, Manager, Regulatory Affairs

Address

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

Phone: [phone]
Fax: [phone]

Date Prepared: 19 July 1996

2. Device Name

Trade Name: Hemagen® Rheumatoid Factor Kit
Common Name: RF (Rheumatoid Factor)
Classification Name: System, Test, Rheumatoid Factor

3. Predicate Device

Hemagen ® RF Kit {Reference 510 (k) No. K 855221/A}

{1}

PAGE 2

## 3. Description of Device

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of IgM rheumatoid factor in human serum and plasma.

The ELISA methodology is commonly used for antibody evaluations. Purified IgG has been attached to the inner surfaces of the microwell plate. During the initial incubation step, rheumatoid factor in patient serum or plasma binds specifically to the immobilized IgG and remains in place after a wash step.

A second antibody which is conjugated to horseradish peroxidase (HRP) is used to recognize the "μ" chain regions of the patient's IgM rheumatoid factor remaining after the wash step. In the wells where the second antibody remains bound, the conjugated HRP catalyzes a color change in the substrate. After the reaction is stopped, the color is read in an EIA Plate reader.

## 4. Intended Use of Device

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of circulating IgM rheumatoid factor. When used according to instructions, the kit is useful in establishing the presence of rheumatoid factor and as an aid in the diagnosis and management of rheumatic diseases.

### 5.(A) Technological Characteristics

#### Proposed Device

The Hemagen Rheumatoid Factor Kit is an enzyme-linked immunosorbent assay. The device utilizes optical density as a measure of antibody presence, with an established cutoff point and equivocal zone, between a positive and a negative reaction.

#### Predicate Device

The Hemagen RF(HA) Kit is a hemagglutination based assay. The device utilizes the method of agglutination of specifically sensitized human erythrocytes by patient serum containing rheumatoid factor. The resultant level of agglutination is used to determine the presence or absence of rheumatoid factor.

{2}

PAGE 3

## 5.(B) Performance Data

### I. Precision

To evaluate precision, inter-assay and intra-assay studies were conducted.

#### A. Inter-assay reproducibility {Between-run}

Eight different serum samples were assayed five times each, twice a day, on five different days (a total of 50 readings)

| Sample | Mean IU/mL | Std. Dev. | % CV | Mean O.D. | Std. Dev. | % CV |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | < 20 | N/A | N/A | 0.038 | 0.005 | 13.1 |
| 2 | < 20 | N/A | N/A | 0.032 | 0.005 | 15.6 |
| 3 | 41.8 | 4.9 | 11.7 | 0.430 | 0.059 | 13.7 |
| 4 | 32.8 | 3.7 | 11.3 | 0.343 | 0.047 | 13.7 |
| 5 | 73.3 | 5.8 | 7.9 | 0.708 | 0.109 | 15.3 |
| 6 | 77.7 | 8.2 | 10.6 | 0.763 | 0.108 | 14.2 |
| 7 | 94.3 | 6.8 | 7.2 | 0.890 | 0.126 | 14.2 |
| 8 | 105.3 | 7.8 | 7.4 | 0.982 | 0.114 | 11.6 |

#### B. Intra-assay reproducibility {Within-run}

Eight different samples were assayed 10 consecutive times in a single run:

| Sample | Mean IU/mL | Std. Dev. | % CV | Mean O.D. | Std. Dev. | % CV |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | < 20 | N/A | N/A | 0.038 | 0.002 | 5.3 |
| 2 | < 20 | N/A | N/A | 0.026 | 0.001 | 3.8 |
| 3 | 37.8 | 3.0 | 7.9 | 0.442 | 0.029 | 6.6 |
| 4 | 31.5 | 3.4 | 10.8 | 0.383 | 0.032 | 8.4 |
| 5 | 74.8 | 3.7 | 4.9 | 0.794 | 0.035 | 4.4 |
| 6 | 71.4 | 4.7 | 6.6 | 0.761 | 0.045 | 5.9 |
| 7 | 89.1 | 2.3 | 2.6 | 0.929 | 0.021 | 2.3 |
| 8 | 100.8 | 4.2 | 4.2 | 1.041 | 0.040 | 3.8 |

### II. Verification of the RF Calibrators

The kit calibrators have been compared to the World Health Organization International Reference Preparation of Rheumatoid Arthritis Serum. A study

{3}

PAGE 4

was conducted to demonstrate the high degree of correlation that exists between the kit calibrators and the W.H.O. Standard.

## III. Comparison Testing

The Hemagen Rheumatoid Factor Kit and the Hemagen RF Hemagglutination Kit were used to assay serum specimens from rheumatoid arthritis patients and normal apparently healthy donors.

Table 1: RF panels, N =106

| Predicate Device | | | |
| --- | --- | --- | --- |
| Proposed Device | Positive | Negative | TOTAL |
| Positive | 73 | 2 | 75 |
| Negative | 4 | 27 | 31 |
| Totals | 77 | 29 | 106 |

The relative analytical sensitivity is (73/77), 94.8 % {87.3 % to 97.9%} 0.95 exact confidence interval
The relative analytical specificity is (27/29), 93.1 % {78.0 % to 98.1 %} 0.95 exact confidence interval

Table 2: Normal blood donors, N = 82

| Predicate Device | | | |
| --- | --- | --- | --- |
| Proposed Device | Positive | Negative | TOTAL |
| Positive | 4 | 0 | 4 |
| Negative | 0 | 78 | 78 |
| Totals | 4 | 78 | 82 |

## IV. Assay performance with Serum and Plasma

Ninety two (92) matched serum and plasma samples were compared. Half of the volume of each sample was converted to serum by recalcification using a standard $\mathrm{Ca}^{2+}$/thrombin methodology.

All of the plasma and converted serum samples were evaluated with the Hemagen Rheumatoid Factor Kit. The results of the evaluation with the proposed device indicate that it can provide accurate estimates of IgM rheumatoid factor in both human serum and plasma.

{4}

PAGE 5

## V. Interfering Substances

Lipemic, hemolytic, and icteric samples were evaluated with the assay. The results indicate that there is no significant effect (&lt; 20 % variation) on the assay for samples with:

- Hemoglobin concentration: ≤ 500 mg/dL
- Lipid concentration: ≤ 3000 mg/dL
- Bilirubin concentration: ≤ 20 mg/dL

## VI. Prozone

The **Hemagen Rheumatoid Factor Kit** was used to assay a high-titered serum sample to determine if the kit would return unexpectedly low values. The results of this evaluation indicate that the kit gives appropriately high positive results with high-titered sera.

## 6. Conclusion

The results of the comparative studies support the claim that the **Hemagen Rheumatoid Factor Kit** is substantially equivalent to the predicate device.