With Zika virus spreading into the southern United States and no commercial test available, physicians can expect to encounter barriers to testing patients who may be infected.
There are only two tests available to detect the Zika virus and not only are they difficult to obtain, they aren’t foolproof in detecting the virus, according to Mia Taormina, DO, an infectious disease specialist and director of a travel medicine clinic near Chicago.
Until last week, the CDC mandated that tests could only be ordered for pregnant women who displayed two out of four symptoms of the Zika virus—conjunctivitis, joint and body aches, low-grade fever and rash.
But guidelines are changing as confirmed cases rise and more is learned about the virus. At this time, all pregnant women who have traveled to endemic areas as listed on the CDC website are advised to contact their obstetrician or gynecologist to see if testing is indicated.
To test a patient for Zika, physicians must gain approval from their local health department after submitting significant paperwork and receiving a case number from the CDC. The patient’s blood work is then sent to the CDC for testing; it can take several weeks to receive results.
The first test, a Zika virus PCR, can identify genetic material from the virus but can only be used within the first few days of the onset of symptoms. By the time a patient is seen by a physician and the physician obtains approval for the test, it’s possible that the virus pathogens are beyond the limit of detection.
A second test, a Zika virus IgM, can test for antibodies in a patient infected with Zika, but it is unclear how long this lab value would remain positive. In addition, there is the possibility of some cross-reaction with other flaviviruses such as dengue and chikungynya.
For the most up-to-date information, follow the CDC’s guidelines on diagnostic testing for Zika.