FDA Approves First Zika Diagnostic Test for Commercial Use

zika test
In response to an emergency request from the CDC, the FDA has agreed to provide a new Zika antibody test to certified labs in the U.S. REUTERS/Gary Cameron

The U.S. Food and Drug Administration (FDA) on Friday approved the use of a tool to diagnose a Zika virus infection after an emergency request by the U.S. Centers for Disease Control and Prevention.

The test, called the CDC Zika IgM Antibody Capture Enzyme-Linked Immunosorbent Assay (Zika MAC-ELISA), is intended for use in detecting antibodies that the body makes to fight off the Zika virus after infection. The test can detect antibodies in blood beginning four to five days after onset of symptoms.

Until now, there has been no FDA-approved commercial diagnostic test for Zika The FDA made the test available under Emergency Use Authorization (EUA), a label reserved for public health emergencies that have "significant potential to affect national security or the health and security of United States citizens." This designation is determined by the U.S. Secretary of Health and Human Services.

The Zika MAC-ELISA is less than ideal; it's not 100 percent accurate. A positive test result indicates that a person was likely infected recently with the Zika virus. On the other hand, a negative test doesn't necessarily mean a person did not have the virus at some point. If the test is used 12 weeks after illness, it is also possible that antibody levels will be too low to be detected.

The test can also deliver a false positive; Zika antibodies may be present when someone has actually been infected with another closely related virus, such as dengue fever.

The CDC will begin distributing the test to CDC-certified laboratories in the next two weeks, but the test currently won't be available in U.S. hospitals or primary care settings, meaning local health authorities will need to reach out to the the CDC and the Laboratory Response Network to order the test for patients.