Zika Testing

Who should be tested for Zika?

YES:

  • Pregnant women with possible exposure to Zika (such as travel or unprotected sex with a partner who might be infected) who have symptoms of Zika virus (fever, rash, headache, joint pain, conjunctivitis [red eyes] or muscle pain)
  • Pregnant women with possible exposure to Zika whose ultrasound shows that her developing baby might have Zika-related birth defects

MAYBE:

Zika testing is not routinely recommended, but may be considered for these groups:

  • Pregnant women with possible exposure to Zika who do not have symptoms
  • Pregnant women who live in or frequently travel to areas with a risk of Zika
  • Non-pregnant people who have symptoms of Zika or dengue. Refer to Testing for Dengue for more information.

NO:

  • Non-pregnant people who do not have symptoms, even if they have possible exposure to Zika

What are the different Zika tests?

Zika Nucleic Acid Amplification Test (NAAT) (also called molecular test) looks for Zika virus in the blood, urine, or other body fluids (not semen). NAAT testing for dengue (a related virus) might be done at the same time as the Zika test.

Zika Antibody Test (also called IgM or serology test) looks for proteins called antibodies that the body makes to fight a Zika infection. These antibodies can be detected for some time after a Zika infection passes. Zika antibody testing is usually performed on the blood or, less frequently, on fluid taken from the spinal column (cerebrospinal fluid). Antibody testing for dengue (a related virus) might be done at the same time as the Zika test.

Plaque Reduction Neutralization Test (PRNT) can be performed after antibody testing to help determine if the antibodies are actually from Zika virus, or if they are from another related virus (like dengue). Sometimes, PRNT testing cannot determine if the antibodies someone has are from Zika or from another related virus.

What are some limitations of the Zika tests?

Testing is not a way to know if it is safe to become pregnant. If you might have been exposed to Zika, you should wait the recommended time (2 months for women, 3 months for men) before trying to conceive a pregnancy.

Testing is not a way to know if you could pass the virus to someone else through sex. If you might have been exposed to Zika, you should take steps to prevent passing Zika to your sex partners. There is no lab test available to look for Zika in the semen.

A negative Zika NAAT test might not mean that you did not have Zika virus. It might just mean that the virus was gone from your blood or urine by the time you were tested. For this reason, Zika antibody testing might be recommended in some situations.

Zika antibody testing can result in a high number of “false positives” in areas where there is not widespread Zika transmission. Since most areas of the world are seeing fewer and fewer cases of Zika, the usefulness of Zika antibody testing has also decreased.

In addition, other related viruses (such as dengue) can cause “false positive” results on Zika antibody tests. Since many parts of the world are seeing an increase in dengue, which has similar symptoms to Zika, testing for dengue instead of Zika might be recommended for many people with symptoms.

Another limitation of Zika antibody testing is that a positive result cannot tell how long ago you became infected with Zika. Timing of an infection is important information for pregnant women or couples planning pregnancy. For people who had only one possible exposure to Zika (for example, a recent trip to an area with Zika), the timing of that trip might help them know when they were infected. But for people with more than one possible exposure or ongoing exposure, a positive antibody test cannot tell them when the infection happened.

Where can I get tested for Zika virus?

Zika testing is available through commercial (private) laboratories, many state health departments, and the Centers for Disease Control and Prevention. Your healthcare provider can contact your state or local health department for testing information.

Some private labs have information about Zika testing on their websites including:

 

When will I get my test results?

Turnaround time for test results varies based on the kind of test, where it is being done, and other factors. If the CDC performs the test, it generally takes about 3 weeks to get the results back to your healthcare provider. If a different lab performs the test, this turnaround time might be longer or shorter.