(270 days)
Elecsys CMV IgG:
The Elecsys CMV IgG immunoassay is a test for the in vitro semi-quantitative determination of IgG class antibodies to CMV in human serum, lithium-heparin plasma, K2 -EDTA plasma, and K3 -EDTA plasma. The test is intended for adults, including expectant mothers, as an aid in presumptive diagnosis of CMV infection. Results with this assay are used to indicate past infection with CMV.
The electrochemiluminescence immunoassay "ECLIA" is intended for use on the indicated Elecsys and cobas e immunoassay analyzers.
This test is not FDA cleared for screening blood or plasma donors.
The performance of this assay has not been established for use in a pediatric population, neonates and immunocompromised patients or for use at point of care facilities.
Elecsys PreciControl CMV IgG:
Elecsys PreciControl CMV IgG is used for quality control of the Elecsys CMV IgG immunoassay on the Elecsys and cobas e immunoassay analyzers.
(1) Elecsys CMV IgG is a two-step sandwich immunoassay with streptavidin microparticles, biotinylated recombinant CMV-specific antigen labeled with a ruthenium complex and electrochemiluminescence detection. The results are determined using a calibration curve which is instrument-specifically generated by a 2-point calibration and a master curve provided via the reagent bar code. Results greater than or equal to 1.0 U/mL are considered reactive CMV IgG antibody. The test system contains the human serum-based calibrators intended for use with the system.
(2) Elecsys PreciControl CMV IgG contains liquid control serum based on human serum. The controls are used for monitoring the accuracy of the Elecsys CMV IgG immunoassay.
Note: The reagent and calibrators are packaged together in the Elecsys CMV IgG assay kit, while the associated PreciControl is packaged separately.
The Elecsys CMV IgG Test System was evaluated through a clinical trial to demonstrate its performance characteristics.
1. Acceptance Criteria and Reported Device Performance
The acceptance criteria for the Elecsys CMV IgG Immunoassay are not explicitly stated as numerical targets in the provided text. Instead, the study reports the "Percent Agreement" values (often referred to as sensitivity and specificity for agreement studies) against a reference method (the predicate device, Diamedix Is-CMV IgG).
| Performance Metric | Acceptance Criteria (Not explicitly stated in document. Based on typical agreement expectations for such assays, good agreement with a predicate is generally sought, e.g., >90%) | Reported Device Performance (Elecsys CMV IgG) | Predicate Device Performance (Diamedix Is-CMV IgG) |
|---|---|---|---|
| Routine Cohort (n=500) | |||
| Positive Percent Agreement (95% CI) | N/A (implied high agreement) | 100% (98.7-100%) | See "Relative Sensitivities" below |
| Negative Percent Agreement (95% CI) | N/A (implied high agreement) | 90.1% (85.3-93.7%) | See "Relative Specificities" below |
| Expectant Mother Cohort (n=98) | |||
| Positive Percent Agreement (95% CI) | N/A (implied high agreement) | 100% (95.4-100%) | Not explicitly provided for this cohort |
| Negative Percent Agreement (95% CI) | N/A (implied high agreement) | 73.7% (48.8-90.9%) | Not explicitly provided for this cohort |
| CMV IgM Positive Cohort (n=119) | |||
| Positive Percent Agreement (95% CI) | N/A (implied high agreement) | 96.6% (91.6-99.1%) | Not explicitly provided for this cohort |
| Negative Percent Agreement (95% CI) | N/A (implied high agreement) | 100% (2.5-100%) | Not explicitly provided for this cohort |
| Predicate Device (Diamedix Is-CMV IgG) relative to EIA (Manual) | |||
| Relative Sensitivities (Site 1, n=195) | N/A | - | 99.3% (96.3-100.0%) |
| Relative Sensitivities (Site 2, n=168) | N/A | - | 96.6% (91.5-99.1%) |
| Relative Sensitivities (Site 3, n=205) | N/A | - | 100.0% (97.6-100.0%) |
| Relative Specificities (Site 1, n=195) | N/A | - | 97.9% (88.9-99.9%) |
| Relative Specificities (Site 2, n=168) | N/A | - | 100.0% (93.0-100.0%) |
| Relative Specificities (Site 3, n=205) | N/A | - | 94.3% (84.3-98.8%) |
| Predicate Device (Diamedix Is-CMV IgG) relative to EIA (Automated) | |||
| Relative Sensitivities (Site 3, n=201) | N/A | - | 100.0% (97.6-100.0%) |
| Relative Specificities (Site 3, n=201) | N/A | - | 87.7% (75.2-95.4%) |
2. Sample Size and Data Provenance
The study included several cohorts for performance evaluation:
- Routine Cohort: n=500
- Expectant Mother Cohort: n=98
- CMV IgM Positive Cohort: n=119
- Cross-Reactivity Cohort: 249 samples positive for various cross-reactants.
The document does not specify the country of origin for the data or whether it was retrospective or prospective.
3. Number of Experts and Qualifications for Ground Truth
The document does not mention the use of human experts or their qualifications for establishing ground truth for the clinical trial comparing the Elecsys CMV IgG immunoassay with the predicate device. The performance is assessed based on agreement with the predicate device results.
4. Adjudication Method
No adjudication method is mentioned in the provided text, as the comparison is made directly against the predicate device's results.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study involving human readers with and without AI assistance was performed, as this device is an in vitro diagnostic immunoassay, not an AI software intended for human interpretation assistance.
6. Standalone Performance (Algorithm Only)
Yes, a standalone study was performed. The Elecsys CMV IgG Immunoassay's performance metrics (Positive Percent Agreement, Negative Percent Agreement) were directly evaluated against the predicate device's results in various clinical cohorts, representing its standalone performance. Additional analytical performance characteristics like precision, LoB/LoD, hook effect, and cross-reactivity were also evaluated for the Elecsys CMV IgG assay itself.
7. Type of Ground Truth Used
The ground truth for the clinical performance evaluation appears to be established by the results of the predicate device, the Diamedix Is-CMV IgG Test System (K981163). The study reports "Percent Agreement" with this predicate device. For the cross-reactivity study, the ground truth was the known positive status for specific cross-reactants.
8. Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of an algorithm or machine learning model for the Elecsys CMV IgG Immunoassay. This device is an immunoassay, and its development likely involves laboratory optimization and validation studies, rather than machine learning training sets. Therefore, a sample size for a training set is not applicable or provided.
9. How the Ground Truth for the Training Set was Established
As noted in point 8, the concept of a "training set" and associated ground truth establishment is not typically applicable to the development of an immunoassay like the Elecsys CMV IgG Test System. The document describes standard laboratory validation procedures and clinical performance evaluation against a predicate device.
§ 866.3175 Cytomegalovirus serological reagents.
(a)
Identification. Cytomegalovirus serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to cytomegalovirus in serum. The identification aids in the diagnosis of diseases caused by cytomegaloviruses (principally cytomegalic inclusion disease) and provides epidemiological information on these diseases. Cytomegalic inclusion disease is a generalized infection of infants and is caused by intrauterine or early postnatal infection with the virus. The disease may cause severe congenital abnormalities, such as microcephaly (abnormal smallness of the head), motor disability, and mental retardation. Cytomegalovirus infection has also been associated with acquired hemolytic anemia, acute and chronic hepatitis, and an infectious mononucleosis-like syndrome.(b)
Classification. Class II (performance standards).