The RUBAscan ® Card Test is a passive latex agglutination test for the detection and/or quantitation of rubella antibodies in human serum. The test is configured to give qualitative results by testing specimens either undiluted or diluted 1:10 to yield two sensitivity levels for detecting rubella antibodies. The choice of protocol used may be based upon judgments concerning the significance of immune status given by antibody levels in protecting the individual from primary rubella infection.

The RUBAscan ® Card Test can also be used to give quantitative results when used to test serial dilutions of the specimen. With properly selected paired specimens, the test can determine recent or active infection.

Device Description

The RUBAscan ® Card Test is based upon the well established principles of passive latex agglutination. Latex is sensitized according to a patented process using solubilized rubella virus antigens from disrupted virions. This latex reagent, when mixed with serum containing rubella antibodies on a card surface, will agglutinate, forming visible clumps. In the absence of antibody, or if the concentration is insufficient to react, the latex will remain smooth and evenly dispersed.

AI/ML Overview

The provided text describes the RUBAscan® Card Test for detecting rubella antibodies. Here's an analysis of its acceptance criteria and supporting studies:

1. Table of Acceptance Criteria and Reported Device Performance:

Acceptance Criteria	Reported Device Performance
Qualitative/Quantitative Sensitivity:
Sensitivity ≥ 95% at 1:10 dilution	- Internal Testing: Met the acceptance criteria (≥ 95%) for sensitivity at the 1:10 dilution. - External Studies: Resolved sensitivity met the 95% confidence intervals including 95% at the two sites. - CDC Evaluation Panel: Identified all 100 samples correctly (100% sensitivity for the samples tested).
Qualitative/Quantitative Specificity:
Specificity ≥ 95% at 1:10 dilution	- Internal Testing: Met the acceptance criteria (≥ 95%) for specificity at the 1:10 dilution. - External Studies: Resolved specificity met the 95% confidence intervals including 95% at the two sites.
Reproducibility:
Acceptable reproducibility at 10 IU/mL	- External Studies: Reproducibility of the RUBAscan® Card Test was acceptable at the 10 IU/mL cut-off.

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

Internal Testing: The specific sample size is not explicitly stated, but it was "in-house testing." The provenance is likely internal (Becton Dickinson Microbiology Systems). It is retrospective as it uses a reference EIA and a latex assay to resolve nonconcordant results.
External Studies: The specific sample size is not explicitly stated. The studies were conducted by "clinical laboratorians" at "two sites," indicating prospective data collection in real-world clinical settings in multiple locations. The country of origin is not specified but generally implies the US for FDA submissions.
CDC Evaluation Panel: 100 samples were tested. The provenance is internal (tested internally by the manufacturer) using a CDC-provided panel, which suggests a well-characterized, standardized set of samples. It is retrospective.

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

The ground truth was not established by individual experts reviewing the test results directly. Instead, it was established by:

Internal Testing: A commercially available Enzyme Immunoassay (EIA) was used as the primary reference standard to establish ground truth, and a commercially available latex assay was used to resolve nonconcordant results. This implies validated commercial diagnostic tests served as the "experts" or gold standard. No individual human experts are mentioned for this purpose.
External Studies: A commercially available EIA was used to define the 10 IU/mL immune status cut-off, serving as the ground truth. Again, no individual human experts are mentioned.
CDC Evaluation Panel: The panel itself serves as the ground truth, meaning the rubella status of each of the 100 samples was already known and established by the CDC. The methodology for this establishment is not detailed in the provided text.

4. Adjudication Method for the Test Set:

Internal Testing: Nonconcordant results (between the RUBAscan® and the primary reference EIA) were resolved using a second, commercially available latex assay. This constitutes an adjudication method, where discrepancies are resolved by a third " Arbiter" test.
External Studies & CDC Evaluation Panel: No specific adjudication method is mentioned beyond the use of the reference EIA or the CDC panel as the definitive ground truth. Discrepancies would likely be considered errors of the RUBAscan® test rather than subject to further adjudication.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

No MRMC study comparing human readers with and without AI assistance was performed or described. This device is a diagnostic kit (latex agglutination test), not an AI-powered image analysis or decision-support system.

6. Standalone Performance:

Yes, the studies describe the standalone performance of the RUBAscan® Card Test. The results (sensitivity, specificity, reproducibility) are reported for the device itself, independently of human interpretation of complex images or data needing AI assistance. The "clinical laboratorians' hands" in the external studies refer to the operational use of the kit rather than subjective interpretation of its output in a way that requires human augmentation by AI.

7. Type of Ground Truth Used:

Reference standard: Commercially available Enzyme Immunoassay (EIA) for internal and external studies.
Reference standard for nonconcordant results: Commercially available latex assay for internal studies.
Pre-established status: A CDC evaluation panel with known rubella status.

This primarily relies on established diagnostic assays and well-characterized reference panels, similar to pathology or highly validated molecular assays in terms of reliability. It is not directly based on expert consensus for each individual case, nor on long-term outcomes data.

8. Sample Size for the Training Set:

The text does not mention a "training set" as this is a traditional diagnostic kit, not a machine learning or AI-based device. Therefore, no training set information is provided.

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

Not applicable, as there is no training set for this type of device.

Summary

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June 14, 1995

SUMMARY OF SAFETY AND EFFECTIVENESS

SUBMITTED BY:

Judith J. Smith Becton Dickinson Microbiology Systems P O Box 243 Cockeysville, MD 21030-0243

NAME OF DEVICE:

Trade Name: Common Name/Description:

Classification Name:

DEC 2 0 1996

RUBAscan® Card Test Latex agglutination for Rubella antibodies Latex agglutination assay, Rubella

PREDICATE DEVICE:

K832228; RUBAscan® Card Test

DEVICE DESCRIPTION:

INTENDED USE: The RUBAscan ® Card Test is a passive latex agglutination test for the detection and/or quantitation of rubella antibodies in human serum. The test is configured to give qualitative results by testing specimens either undiluted or diluted 1:10 to yield two sensitivity levels for detecting rubella antibodies. The choice of protocol used may be based upon judgments concerning the significance of immune status given by antibody levels in protecting the individual from primary rubella infection.

KIT DESCRIPTION: The RUBAscan ® Card Test is based upon the well established principles of passive latex agglutination. Latex is sensitized according to a patented process using solubilized rubella virus antigens from disrupted virions. This latex reagent, when mixed with serum containing rubella antibodies on a card surface, will agglutinate, forming visible clumps. In the absence of antibody, or if the concentration is insufficient to react, the latex will remain smooth and evenly dispersed.

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A single specimen can be used to obtain a qualitative judgment about its antibody content. Analysis of dilutions of the specimen can give quantitative results.

PERFORMANCE DATA:

Clinical Correlation: The following studies were conducted to enable the addition of a quantitative sensitivity claim of 10 IU/mL at the 1:10 screening dilution. The NCCLS guideline I/LA6-T was used as a guideline for performing the testing.

. Internal testing was conducted to validate that the RUBAscan® Card Test dilution of 1:10 is equivalent to the 10 IU/mL cut-off.
Conclusion: The RUBAscan® Card Test met the acceptance criteria (≥ 95% as suggested by the NCCLS guidelines) for sensitivity and specificity of the in-house testing at the dilution of 1:10 when a commercially available ElA was used as the reference and a commercially available latex assay was used to resolve nonconcordant results.
. Two external studies were conducted to validate that the screening dilution of the RUBAscan® Card Test in clinical laboratorians' hands was equivalent to the 10 IU/mL immune status cut-off as defined by the commercially available EIA.
Conclusion: The RUBAscan® Card Test resolved sensitivity and specificity met the 95% confidence intervals for the observed sensitivity and specificity including 95% at the two sites.
. A CDC evaluation panel was tested internally using a 1:10 dilution.
Conclusion: The RUBAscan® Card Test identified all 100 samples correctly.

Beproducibility:

. Two external studies were conducted to validate dilution reproducibility at the 10 IU/mL cut-off.
Reproducibility of the RUBAscan® Card Test was Conclusion: acceptable.

Regulation Number and Section

§ 866.3510 Rubella virus serological reagents.

(a)
Identification. Rubella virus serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to rubella virus in serum. The identification aids in the diagnosis of rubella (German measles) or confirmation of a person's immune status from past infections or immunizations and provides epidemiological information on German measles. Newborns infected in the uterus with rubella virus may be born with multiple congenital defects (rubella syndrome).(b)
Classification. Class II. The special controls for this device are:(1) National Committee for Clinical Laboratory Standards':
(i) 1/LA6 “Detection and Quantitation of Rubella IgG Antibody: Evaluation and Performance Criteria for Multiple Component Test Products, Speciment Handling, and Use of the Test Products in the Clinical Laboratory, October 1997,”
(ii) 1/LA18 “Specifications for Immunological Testing for Infectious Diseases, December 1994,”
(iii) D13 “Agglutination Characteristics, Methodology, Limitations, and Clinical Validation, October 1993,”
(iv) EP5 “Evaluation of Precision Performance of Clinical Chemistry Devices, February 1999,” and
(v) EP10 “Preliminary Evaluation of the Linearity of Quantitive Clinical Laboratory Methods, May 1998,”
(2) Centers for Disease Control's:
(i) Low Titer Rubella Standard,
(ii) Reference Panel of Well Characterized Rubella Sera, and
(3) World Health Organization's International Rubella Standard.