(269 days)
The EUROIMMUN Anti-West Nile Virus ELISA (IgM) is intended for the qualitative detection of IgM antibodies to West Nile virus in human serum and plasma (K+EDTA, Li+-heparin). This test is intended as an aid in the presumptive laboratory diagnosis of West Nile virus infection in patients with clinical symptoms consistent with meningitis/encephalitis, in conjunction with other laboratory and clinical findings. Positive results must be confirmed by the plaque reduction test (PRNT) or by using the current CDC guidelines for diagnosis of this disease.
The assay characteristics have not been established for testing cord blood, neonates, prenatal screening, and general population screening of patients without symptoms of meningoencephalitis. This assay is not FDA cleared or approved for testing blood or plasma donors.
Warning: Cross-reactivity with IgM to Dengue virus, Malarialanti-Plasmodium falciparum and Parvovirus B19 has been observed with the EUROIMMUN Anti-West Nile Virus ELISA (IgM). Reactive results must be reported with a caution statement regarding possible IgM cross-reactivity with other flaviviruses.
Patient serum or plasma samples are diluted 1:101 in sample buffer and incubated for 10 minutes at room temperature to allow IgG/RF separation. 100 ul of each diluted patient sample and pre-diluted controls and calibrator are added to the antigen coated microtiter wells and incubated for 60 minutes at +37°C. After incubation the microtiter well strips are washed 3 times with wash buffer to remove unbound antibodies and 100 ul of the anti-human IgM enzyme conjugate reagent is added to each microtiter well. After an additional 30 minutes incubation at room temperature, the microtiter wells are again washed 3 times with wash buffer to remove any unbound enzyme conjugate and 100 ul of the chromogen substrate is added. The strips are incubated for 15 minutes at room temperature and 100 ul stop solution is added. The microtiter placed in an ELISA reader and read at a wavelength of 450 nm and a reference wavelength of between 620 nm and 650 nm within 30 minutes.
Here's an analysis of the provided text regarding the acceptance criteria and study for the EUROIMMUN Anti-West Nile Virus ELISA (IgM):
Note: This document describes an in vitro diagnostic (IVD) device, not a typical AI/ML device. Therefore, the concepts of "test set," "training set," "experts to establish ground truth," "adjudication method," and "MRMC comparative effectiveness study" do not directly apply in the same way they would to an AI-powered image analysis or diagnostic tool. Instead, the performance is evaluated against a predicate device and/or a reference standard like PRNT (Plaque Reduction Neutralization Test), and clinical studies involve comparisons of the device's results with these established methods.
Acceptance Criteria and Reported Device Performance
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for this device, being a diagnostic test, are generally based on sensitivity and specificity relative to a reference standard or a predicate device. The document explicitly states the ranges for these measures.
| Acceptance Criteria Category | Acceptance Criteria (Implicit from Clinical Studies) | Reported Device Performance (Range) |
|---|---|---|
| Sensitivity | High sensitivity (e.g., >80-90%) | 84.0% (89.9% in Clinical Study III) |
| Specificity | High specificity (e.g., >90-95%) | 97.3% (from Assay Cut-off section for healthy donors); 99.7% in Clinical Study II |
| Positive Agreement | High agreement with predicate device (e.g., >85%) | 85.7% (Clinical Study I); 90.9% (Clinical Study II); 89.9% (Clinical Study III) |
| Negative Agreement | High agreement with predicate device (e.g., >95%) | 97.3% (Clinical Study I); 99.7% (Clinical Study II) |
| Repeatability (CV%) | Low Coefficient of Variation (e.g., |
§ 866.3940 West Nile virus serological reagents.
(a)
Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum, from individuals who have signs and symptoms consistent with viral meningitis/encephalitis. The detection aids in the clinical laboratory diagnosis of viral meningitis/encephalitis caused by West Nile virus.(b)
Classification. Class II (special controls). The special control is FDA's guidance entitled “Class II Special Controls Guidance Document: Serological Reagents for the Laboratory Diagnosis of West Nile Virus.” See § 866.1(e) for the availability of this guidance document.