Zika Tests And What We Know About Them

Aug 15, 2016

The Centers for Disease Control and Prevention (CDC) has approved two types of testing for Zika virus in humans. Generally, the type of test to be used will depend on the "exposure date" or when the patient believes he or she has been exposed to the virus.

The first type of tests are the Reverse-Transcription-Polymerase Chain Reaction Tests (RT-PCR).

The RT-PCR tests can detect the Zika virus' DNA through the blood and urine of the patient, as long it is collected within 14 days of the onset of the symptoms. The blood test can detect the Zika DNA up to two weeks after the patient may have been infected. The urine test can detect it up to four weeks after infection. Dr. Ellen Schwartzbard, an OB-GYN at South Miami Hospital, said she uses RT-PCR tests in her practice. 

“For now, to know if you're infected within the last four weeks, I think, is a reasonable test to do," Schwartzbard said. "The problem with the Zika virus is the majority of patients may have an infection, but not show any symptoms."

The M Antibody-Capture Enzyme-Linked Immunosorbent Tests 

The MAC-ELISA test looks for antibodies generated in response to the virus. The antibodies stay in the body longer than the actual virus itself, even after the individual gets rid of the disease,  so the MAC-ELISA test can check for the Zika virus antibodies from two to 12 weeks after exposure. It's administered through a blood test that looks specifically at plasma. Dr. Marcia Eisenberg, the chief scientific officer of LabCorp Diagnostics' lab, which offers the MAC-ELISA test, says mostly everyone recovers from Zika months after acquiring it, but her main concern is for developing fetuses whose mother contracts the disease during pregnancy. “I think what is different is the impact of the virus to the developing baby, but the woman herself would actually technically not have the virus just like you would recover from the cold or the flu," Dr. Eisenberg said. Individuals asking for the MAC-ELISA test must first meet  requirements placed by the CDC. Getting the test results may take up to two to four weeks depending on whether the local health care provider has authority from the CDC to test for Zika in its own laboratories, or if it must send specimens to the CDC to screen for the virus.