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 Description

An enzvme-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 "u" chain regions of the patient's IgM rheumatoid factor remaining after the wash step. In the wells where the second antibody remains bound. the coniugated HRP catalyzes a color change in the substrate. After the reaction is stopped, the color is read in an EIA Plate reader.

AI/ML Overview

Here's an analysis of the provided text, focusing on the acceptance criteria and the supporting study, structured as requested:

Acceptance Criteria and Study Details for Hemagen® Rheumatoid Factor Kit

1. Table of Acceptance Criteria and Reported Device Performance

Based on the provided text, the acceptance criteria are largely implied by the performance metrics reported. The study aimed to demonstrate substantial equivalence to a predicate device.

Performance Metric	Acceptance Criteria (Implied)	Reported Device Performance
Precision (Inter-assay)	Low %CV (indicating acceptable variability between runs)	Mean %CV for IU/mL: Range from 7.2% to 11.7% (for positive samples). Mean %CV for O.D.: Range from 11.6% to 15.6%.
Precision (Intra-assay)	Low %CV (indicating acceptable variability within a single run)	Mean %CV for IU/mL: Range from 2.6% to 10.8% (for positive samples). Mean %CV for O.D.: Range from 2.3% to 8.4%.
Correlation with WHO Standard (Calibrators)	High degree of correlation with WHO International Reference Preparation	A study was conducted to demonstrate a "high degree of correlation" (specific numerical criteria not provided).
Relative Analytical Sensitivity	Acceptable sensitivity compared to the predicate device	94.8% (95% CI: 87.3% to 97.9%) compared to the predicate device in the RF panels.
Relative Analytical Specificity	Acceptable specificity compared to the predicate device	93.1% (95% CI: 78.0% to 98.1%) compared to the predicate device in the RF panels.
Performance with Normal Blood Donors	Low false positive rate compared to predicate device	In a panel of normal blood donors (N=82): 4 positives by proposed device, 4 positives by predicate, 78 negatives by both. No false positives/negatives detected by either device compared to the other.
Assay Performance with Serum and Plasma	Accurate estimates of IgM RF in both serum and plasma	Results indicate the kit "can provide accurate estimates of IgM rheumatoid factor in both human serum and plasma." (Specific quantitative equivalence not provided).
Interfering Substances (Hemoglobin)	< 20% variation in assay performance	≤ 500 mg/dL hemoglobin concentration: No significant effect (< 20% variation).
Interfering Substances (Lipid)	< 20% variation in assay performance	≤ 3000 mg/dL lipid concentration: No significant effect (< 20% variation).
Interfering Substances (Bilirubin)	< 20% variation in assay performance	≤ 20 mg/dL bilirubin concentration: No significant effect (< 20% variation).
Prozone Effect	No unexpectedly low values with high-titered serum	Kit "gives appropriately high positive results with high-titered sera." (Specific data not provided).

2. Sample Size Used for the Test Set and Data Provenance

RF Panels (Comparison Testing): N = 106 serum specimens (from rheumatoid arthritis patients and apparently healthy donors).
Normal Blood Donors (Comparison Testing): N = 82 samples.
Serum and Plasma Comparison: N = 92 matched serum and plasma samples.
Precision Studies: 8 different serum samples (repeated multiple times).
Interfering Substances: Specific number of samples not stated, but "samples" were evaluated.
Prozone: A "high-titered serum sample" was used (singular).

Data Provenance: The text does not explicitly state the country of origin or whether the data was retrospective or prospective. Given the medical device submission context, it's highly likely it was prospective testing conducted for the purpose of the submission. The "serum specimens from rheumatoid arthritis patients and normal apparently healthy donors" suggests typical clinical samples.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The provided text does not mention the use of experts to establish ground truth for the test set. The ground truth appears to be established by comparison to the predicate device (Hemagen RF Hemagglutination Kit) and clinical classifications (rheumatoid arthritis patients and normal donors).

4. Adjudication Method for the Test Set

No adjudication method is described. The comparison is directly between the proposed device and the predicate device, seemingly on a sample-by-sample basis.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

No MRMC study was done. This document describes the performance of an in vitro diagnostic (IVD) kit, not an AI-assisted diagnostic tool that would involve human readers interpreting results. Therefore, the concept of "human readers improve with AI" is not applicable.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done

Yes, this entire study describes the standalone performance of the Hemagen® Rheumatoid Factor Kit (an ELISA assay). It is an algorithm-only (in the sense of a defined chemical/enzymatic process with a quantitative output read by a machine) performance without human interpretation or intervention in the diagnostic process itself. The interpretation of the optical density into IU/mL and its classification as positive/negative based on a cutoff is inherent to the kit's design.

7. The Type of Ground Truth Used

The primary ground truth used for performance evaluation (specifically sensitivity and specificity) is the predicate device (Hemagen RF Hemagglutination Kit). Additionally, for the comparison testing, samples were drawn from "rheumatoid arthritis patients" and "normal apparently healthy donors," implying a clinical diagnosis (outcomes data) based on established medical criteria as a secondary ground truth, against which both the proposed and predicate device were compared.

8. The Sample Size for the Training Set

No training set is mentioned in the document. This is an IVD kit describing analytical performance, not a machine learning model that would typically have a distinct training set.

9. How the Ground Truth for the Training Set Was Established

Not applicable, as no training set for a machine learning model is described.

Summary

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SEP 12 1986

PAGE l

长962836 510(k) Summary

Submitter's Name/Contact Person 1.

Joseph M. Califano, Manager, Regulatory Affairs

Address

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

(617) 890-3766 Phone: Fax: (617) 890-3748

Date Prepared: 19 July 1996

2. Device Name

ﻤﺴﺘﻌﻤ

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}

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3. Description of Device

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

4. Intended Use of Device

Technological Characteristics 5.(A)

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.

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5.(B) Performance Data

1. Precision

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

Inter-assay reproducibility {Between-run} A.

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

Verification of the RF Calibrators ll.

ﻣﻨﺘﺴﺘﻌﺎ

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

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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 %) 0.9 axed confience internal

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 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.

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Interfering Substances V.

Lipemic, hemolytic, and icteric samples were evaluated with the assay. The results indicate that there is no significant effect (< 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.

Regulation Number and Section

§ 866.5775 Rheumatoid factor immunological test system.

(a)
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.(b)
Classification. Class II (performance standards).