(220 days)
The Elecsys Rubella IgM immunoassay is for the in vitro qualitative determination of IgM antibodies to rubella virus in human serum and Li-heparin, K3-EDTA, and sodium citrate plasma. This assay may be used as an aid in the presumptive diagnosis of an acute or recent rubella infection in individuals, including women of childbearing age. The electrochemiluminescence immunoassay "ECLIA" is intended for use on the Elecsys and cobas e immunoassay analyzers. NOTE: This assay has not been cleared/approved by the FDA for blood/plasma donor screening.
Elecsys PreciControl Rubella IgM is used for quality control of the Elecsys Rubella IgM immunoassay on the Elecsys and cobas e immunoassay analyzers.
(1) The Elecsys Rubella IgM Immunoassay is a two-step sandwich immunoassay with streptavidin microparticles and electrochemiluminescence detection. The Rubella IgM is composed of a biotin-labeled monoclonal antibody-against-human IgM, a Rubella-like particle and a ruthenium-labeled anti-Rubella antibody. A relationship exists between the concentration of the IgM antibody targets present in a patient sample and the level of signal count detected by the system. The IgM assay is a qualitative test based on a cut-off formula dependent on the negative and positive calibrators. Cut-off index (COI) is based on the ratio of assay signal to cut-off signal (also abbreviated s/co). COI values equal to or greater than 1.0 are considered positive for the presence of anti-Rubella IgM antibody. Results are determined using a 2 point calibration. The test system contains the human serum-based calibrators intended for use with the system.
(2) The Elecsys PreciControl Rubella igM contains two levels of human serum. The positive control contains native, inactivated Rubella IgM antibodies.
Here's a breakdown of the requested information based on the provided text for the Elecsys Rubella IgM Test system.
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state formal "acceptance criteria" with numerical thresholds for performance metrics. Instead, it presents performance data (e.g., agreement percentages) as part of the method comparison with predicate devices.
| Metric (Type of Agreement) | Acceptance Criteria (Not explicitly stated as criteria in document) | Reported Device Performance (Elecsys vs. Predicate) | Notes |
|---|---|---|---|
| Pregnant Subjects | Against Zeus Scientific/Abbott AxSym and DPC Immulite | ||
| Negative Agreement | N/A | 99.20% (131/132) [95.90%-99.98% CI] | Very high agreement for negative cases |
| Positive Agreement | N/A | 0.00% (0/0) [0%-100% CI] | No positive rubella IgM cases found in pregnant subjects within this specific comparison |
| Non-Pregnant Subjects | Against Zeus Scientific/Abbott AxSym and DPC Immulite | ||
| Negative Agreement | N/A | 98.90% (364/368) [97.20-99.70% CI] | Very high agreement for negative cases |
| Positive Agreement | N/A | 0.00% (0/1) [0.00-97.5% CI] | Only one positive rubella IgM case found, and the Elecsys device did not agree. The wide CI reflects the small sample size. |
| Analytical Specificity (against predicate) | N/A | 77.6% agreement with predicate for 60 specimens representing a variety of disease states | This indicates how well the assay differentiates Rubella IgM from other conditions. |
| Precision | Various CVs (Coefficient of Variation) are reported for intra-assay and inter-assay precision for different control levels and plasma samples. The predicate also reports CVs. These are performance characteristics rather than explicit acceptance criteria. |
2. Sample Sizes Used for the Test Set and Data Provenance
- Test Set Sample Sizes:
- Method Comparison (Elecsys vs. Zeus Scientific/Abbott AxSym and DPC Immulite):
- Pregnant Subjects: 132 (131 negative, 0 positive)
- Non-Pregnant Subjects: 369 (368 negative, 1 positive)
- This totals 501 samples for the method comparison.
- Analytical Specificity: 60 specimens.
- Method Comparison (Elecsys vs. Zeus Scientific/Abbott AxSym and DPC Immulite):
- Data Provenance: The document does not explicitly state the country of origin of the data. It also does not explicitly state if the data was retrospective or prospective.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
The document does not provide information regarding the number of experts used to establish ground truth or their qualifications. The "ground truth" for the method comparison appears to be established by the results of the predicate devices (Zeus Scientific Rubella IgM ELISA Test System, Abbott AxSym, and DPC Immulite).
4. Adjudication Method for the Test Set
The document does not specify any adjudication method (e.g., 2+1, 3+1). The comparison is directly made against the results of the predicate devices.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
No, an MRMC comparative effectiveness study involving human readers and AI assistance was not mentioned or conducted. This device is an in-vitro diagnostic (IVD) immunoassay, not an AI-assisted diagnostic tool for human readers.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, the performance data presented (e.g., method comparison, analytical specificity, precision) represents the standalone performance of the Elecsys Rubella IgM Immunoassay system. Since it's an automated immunoassay, its performance is inherently "standalone" without direct human-in-the-loop interaction in the diagnostic step (though human operators initiate and interpret the results).
7. The Type of Ground Truth Used
The primary "ground truth" used for evaluating the Elecsys Rubella IgM Immunoassay appears to be:
- Predicate Device Results: For the method comparison, the results from the legally marketed predicate devices (Zeus Scientific Rubella IgM ELISA Test System, Abbott AxSym, and DPC Immulite) served as the reference for determining agreement.
- The document also implies other laboratory methods were used for the "analytical specificity" though more detail is not provided.
8. The Sample Size for the Training Set
The document does not provide information regarding a "training set" size. As an immunoassay, the device is developed and validated through analytical studies and clinical comparisons, rather than a machine learning approach that typically involves distinct training and test sets.
9. How the Ground Truth for the Training Set Was Established
Since a "training set" is not mentioned in the context of this immunoassay's development, the document does not describe how ground truth for a training set was established. The development of such assays typically involves optimizing reagents and protocols to achieve desired analytical performance and then validating that performance against established methods and clinical samples.
§ 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.