Zika Testing

This page talks about who should be tested for Zika, the kinds of Zika tests and what the results might mean, and how to get tested.

First, some helpful definitions:

  • “Possible exposure to Zika” means that you live in or recently traveled to an area with Zika, or had unprotected sex with someone who lives in or traveled to an area with Zika.
  • Ongoing possible exposure” means that you live in or regularly travel (such as daily or weekly) to an area with Zika, or you regularly have unprotected sex with someone who lives in, regularly travels to, or was in an area with Zika.
  • Symptomatic means having or recently having symptoms of Zika virus, such as fever, rash, headache, joint pain, conjunctivitis (red eyes) or muscle pain.
  • Asymptomatic means having no symptoms of Zika virus.
Who should be tested for Zika?

The CDC recommends Zika testing for:

  • Anyone with possible exposure to Zika who has or recently had symptoms of Zika virus
  • Symptomatic pregnant women with possible exposure to Zika
  • Asymptomatic pregnant women with ongoing possible exposure to Zika
  • Any pregnant woman with possible exposure to Zika whose ultrasound shows that her developing baby might have birth defects related to Zika

Testing is not routinely recommended but can be considered for:

  • Asymptomatic pregnant women with recent possible exposure to Zika, but no ongoing exposure

Testing is NOT recommended for:

  • Men, non-pregnant women and children who do not have symptoms, even if they had possible exposure to Zika

Testing is not the best way to know if it is safe to become pregnant. If you might have been exposed, you should wait the recommended time before trying to conceive a pregnancy (see How to Prevent Getting or Spreading the Zika Virus).

Testing is not the best way to know if you could pass the virus to someone else through sex. If you might have been exposed, you should take steps to prevent passing Zika to someone else (see How to Prevent Getting or Spreading the Zika Virus).

Together, you and your health care provider can decide whether or not you should be tested for Zika, based on your individual circumstances. These charts can help healthcare providers make decisions about how and when to test for Zika:

Testing Guidance
Zika Testing Algorithm for Symptomatic Pregnant Women
Zika Testing Algorithm for Asymptomatic Pregnant Women

Kinds of Zika virus tests

1) Nucleic Acid Testing (NAT) looks for Zika virus, usually in blood or urine.

NAT testing is recommended for:

  • Anyone with possible exposure to Zika who has had symptoms of Zika virus starting within the last two weeks
  • Pregnant women with possible exposure to Zika who have had symptoms of Zika virus starting any time within the last twelve weeks (test as soon as possible along with antibody testing)
  • Asymptomatic pregnant women with ongoing possible exposure to Zika (NAT testing recommended three times during the pregnancy, beginning at the first prenatal visit)
  • Pregnant women with possible exposure to Zika whose ultrasound shows that her developing baby might have birth defects related to Zika (done along with antibody testing)

What do my results mean?

  • Usually, a positive NAT test for Zika means that you have Zika virus, and no other testing is needed.
  • A negative result doesn’t necessarily mean that you don’t have Zika virus; it might just mean that the virus is no longer detectable in your body. Your health care provider might still recommend antibody testing to try and rule out Zika virus.

2) Antibody Testing (also called serologic or IgM testing) looks for proteins the body makes to fight a Zika infection. These proteins, called antibodies, can be detected in the body for some time after a Zika infection. Antibody testing is usually performed on the blood or on fluid taken from the spinal column (cerebrospinal fluid).

Antibody testing is recommended for:

  • Anyone (not pregnant) with possible exposure to Zika who had symptoms of Zika virus starting within the last 2-12 weeks
  • Pregnant women with possible exposure to Zika who have had symptoms of Zika virus starting any time within the last twelve weeks (test as soon as possible along with NAT testing)
  • Pregnant women with possible exposure to Zika whose ultrasound shows that her developing baby might have birth defects related to Zika (done along with NAT testing)
  • Symptomatic people who have had a negative NAT test, as a follow-up to try and rule out Zika virus

What do my results mean?

  • A negative Zika antibody test (along with a negative NAT test, if performed) usually means there is no evidence of Zika virus infection and no need for further testing.
  • A positive or unclear antibody test result might be confirmed by another test called a Plaque Reduction Neutralization Test (PRNT). The PRNT test helps find out if the antibodies you have are actually from Zika virus, or if they are from another related virus, such as dengue. Sometimes, PRNT testing cannot determine if the antibodies you have are from Zika or from another related virus.

Limitations of antibody testing:

Zika antibodies might be detected in some people’s bodies for longer than in others’. For this reason, a positive antibody test might not be able to tell how long ago you were infected with Zika. For people who had only one possible exposure to Zika (for example, a trip to an area with Zika), the timing of the exposure might help determine 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.

Another limitation to antibody testing is that even a very good test can result in a high number of false positives in areas where there is not widespread Zika transmission. Since many areas with Zika are seeing fewer and fewer cases, the usefulness of antibody testing has also decreased. For this reason, antibody testing is not usually recommended for people who have not had symptoms of Zika, even if they are pregnant.

How to get tested for Zika virus

The Centers for Disease Control and Prevention (CDC), along with state and local health departments, are testing for Zika virus. Your health care provider can contact your state or local health department for testing information.

Some private labs also offer Zika testing. Information on the specific testing, time to results, forms and who qualifies for testing can be found on the companies’ websites including: