Paired serum and urine are the primary diagnostic specimens for Zika virus infection.7
Multiple assays and sample types are often needed to establish a definitive laboratory diagnosis of Zika virus infection. The recommended tests include Zika virus RNA and/or IgM antibody tests. It is further recommended that all persons suspected of having Zika infection should also be tested for chikungunya and dengue infections. The symptoms overlap, and the viruses are transmitted in the same regions by the same mosquito vector.
Zika virus RNA testing should be performed during the acute phase of infection, generally up to 2 weeks after onset of symptoms. However, viral RNA may be detectable in urine longer than 2 weeks after symptom onset. Data suggest that Zika virus RNA may be detectable longer in pregnant women; therefore, guidelines recommend RNA testing in symptomatic pregnant women through 12 weeks after symptom onset.7
Zika virus IgM antibodies rise shortly after symptom onset and persist for up to 12 weeks or longer for months after infection, making it difficult to use Zika virus IgM tests to determine if women might have been infected before or after they became pregnant.7 The Zika virus IgM antibody test can exhibit cross-reactivity with antibodies from other flavivirus infections, such as dengue, West Nile, and yellow fever. Thus, confirmation of a Zika virus IgM non-negative test result should be conducted according to CDC algorithms. As the prevalence of Zika virus disease declines, the lower prevalence increases the probability that positive test results are false-positives.7
Refer to CDC.gov/zika/laboratories/lab-guidance.html for the CDC’s guidance for laboratory testing.