The Zika virus MAC-enzyme-linked immunosorbent assay (ELISA) is useful as a qualitative screen for the presence of IgM-class antibodies to Zika virus. A presumptive positive result by this assay is not diagnostic for Zika virus infection. All presumptive positive, equivocal or inconclusive results by this assay must be confirmed by a plaque reduction neutralization test (PRNT) performed at the CDC or by a molecular test for detection of Zika virus RNA. For existing clients, the Zika MAC-ELISA will only be offered in the United States and U.S. territories.
The CDC requires that all specimens tested for Zika virus IgM antibodies also be tested for IgM antibodies to dengue virus due to the possibility of cross-reactivity between these 2 closely related flaviviruses.
A single negative result should not be used to rule-out infection with Zika or dengue virus as the specimen may have been collected prior to the development of detectable antibodies.
|Who Should Receive this Test?
|Zika MAC-ELISA: IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) can be used to document a serologic response to Zika virus infection. ELISA is less subjective than immunofluorescence and large numbers of samples can be processed. Anti-IgM (the capture antibody) is coated on 96-well plates. This is followed sequentially by adding the patient's serum, then known noninfectious viral antigen. The presence of antigen is detected by using enzyme-conjugated antiviral antibody. A colorimetric result is generated by the interaction of the enzyme and a chromogenic substrate. This colorimetric change is detected by a spectrophotometer (ELISA reader).(Package insert: Zika MAC-ELISA, CDC, Atlanta, GA)
DENV Detect IgM Capture ELISA: Samples and controls are diluted in sample dilution buffer and incubated in microtiter wells coated with antihuman-IgM antibodies. This incubation is followed by incubation with dengue-derived recombinant antigens (DENRA) and normal cell antigen (NCA) separately. After incubation and washing, the wells are treated with a dengue-specific monoclonal antibody labeled with horseradish peroxidase (HRP). After a second incubation and washing step, the wells are incubated with tetramethylbenzidine (TMB) substrate. Acid stop is added and absorbance at 450 nm is read. Ratio of absorbencies of the DENRA and the control antigen wells determine whether the result is positive or negative.(Package insert: InBiOS DENV Detect IgM CAPTURE ELISA version 900106-03 8/16/2011. InBios International, Inc, Seattle WA)
|Day(s) and Time(s) Test Performed: Monday, Tuesday, Wednesday, Thursday; noon
Analytic Time: 3 days