Diagnosis of Zika infection is complex. Molecular tests for exposure are only reliable in the first two to three weeks after infection. Antibody tests are confounded by cross-reactivity of antibodies to Zika with similar viruses like dengue and yellow fever. A new blood test called ZIKV-NS2B-concat ELISA is faster, less expensive, and extends the window of accurate detection to months after onset of infection, giving clinicians a powerful tool to screen for Zika throughout pregnancy.