(273 days)
The INCSTAR Rubella IgG "fast" ELISA Kit contains instructions and materials for the qualitative and/or semi-quantitative detection of IgG antibodies to rubella in human serum by indirect enzyme-linked immunosorbent assay (ELISA) technique. When performed according to instructions, the Rubella IgG "fast" ELISA test is of value in the determination of rubella immunological status. The evaluation of paired sera, acute and convalescent, by demonstrating seroconversion or a significant rise in antibody can aid in the diagnosis of current or recent infection with rubella.
The INCSTAR Rubella IgG "fast" ELISA test kit utilizes the ELISA technique for the detection of rubella IgG antibodies. Diluted patient serum is incubated with purified rubella antigen bound to the solid surface of a microtiter well. If IgG antibodies to rubella are present in the patient's serum, antigen-antibody complexes are formed. These complexes bind with horseradish peroxidase labeled antihuman IgG which react with the addition of chromogen, resulting in color development. The absorbance of the solution, measured at 450 nm, is directly proportional to the concentration of IgG antibodies to rubella antigen present in the reaction solution.
This document describes the safety and effectiveness of the INCSTAR Rubella IgG "fast" ELISA Kit by comparing it to a previously cleared device. The study is a retrospective analysis of human serum samples.
1. Table of Acceptance Criteria and Reported Device Performance:
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance (95% CI) |
|---|---|---|
| Relative Sensitivity | High (e.g., >90%) | 91% to 100% |
| Relative Specificity | High (e.g., >95%) | 97% to 100% |
| Overall Agreement | High (e.g., >95%) | 97% to 99% |
Note: The document states the device is "substantially equivalent" to a predicate device, implying that the acceptance criteria are met if its performance is comparable to the predicate device within acceptable statistical bounds.
2. Sample Size and Data Provenance:
- Test Set Sample Size: 497 serum samples.
- Data Provenance: The samples were from a mixed population of clinical patients (non-rubella disease related), newborns, employee/student screenings, and pregnant women. The country of origin is not explicitly stated, but given the 510(k) submission to the FDA, it is highly likely the data includes samples collected in the United States. The study is retrospective, as it compares the performance of a new kit against an existing one using collected samples.
3. Number of Experts and Qualifications:
- Not Applicable. This study is a diagnostic device performance study comparing two ELISA kits using human serum samples. The ground truth is established by the results of a predicate device and a third reference assay, not by expert interpretation of clinical data in the traditional sense of medical imaging or clinical diagnosis.
4. Adjudication Method for the Test Set:
- The primary comparison was between the INCSTAR Rubella IgG "fast" ELISA Kit and the Rubella IgG Clin-ELISA kit (the predicate device).
- For discrepant results between these two assays, a third commercial Rubella IgG EIA (Abbott Rubazyme EIA) was used for "further resolution." This acts as an adjudication step, though not explicitly a consensus panel. For example:
- 5 samples were positive by INCSTAR but negative by the reference ELISA; 3 of these were found positive by Rubazyme.
- 3 samples were negative by INCSTAR but positive by the reference ELISA; 2 of these were found negative by Rubazyme.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No. This is a diagnostic assay comparison, not an MRMC study involving human readers interpreting clinical cases.
6. Standalone Performance:
- Yes, in the context of a diagnostic kit. The reported performance metrics (relative sensitivity, relative specificity, overall agreement) reflect the standalone performance of the INCSTAR Rubella IgG "fast" ELISA Kit when compared against the defined "ground truth" (the predicate device and the adjudicating third assay).
7. Type of Ground Truth Used:
- The ground truth in this study is based on the results of a predicate device (Rubella IgG Clin-ELISA kit), supplemented by a third commercial Rubella IgG EIA (Abbott Rubazyme EIA) for resolving discrepant cases. This is a common method for establishing "ground truth" in diagnostic kit comparisons, where a well-established and cleared assay serves as the reference.
8. Sample Size for the Training Set:
- Not explicitly stated in this summary. This document describes a clinical performance study for validation and comparison, not the development process. Therefore, information about the training set used during the development of the INCSTAR Rubella IgG "fast" ELISA Kit is not provided here.
9. How the Ground Truth for the Training Set Was Established:
- Not explicitly stated in this summary. As per point 8, this document focuses on the validation study. The method for establishing ground truth during the original development and training phases of the kit would not typically be included in a 510(k) summary focused on clinical performance data.
§ 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.