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The Zika virus (ZIKV) is spread primarily by the bite of infected mosquitoes, though it can also be transmitted in other ways, including during sex and from a pregnant person to a fetus. This virus is part of the family of viruses known as Flaviviruses which includes the viruses that cause dengue infection, chikungunya disease, and yellow fever.

Infection with Zika virus is generally mild, although serious health consequences occur in a minority of patients. Infection during pregnancy can cause birth defects and other health issues.

A sample of blood or urine is used to detect a Zika virus infection. Zika virus testing is only recommended for individuals with symptoms of a Zika infection who have traveled to a country with a Zika virus outbreak.

About the Test

Purpose of the test

The purpose of testing for the Zika virus is to determine if a patient has a Zika virus infection.

Zika virus testing is diagnostic, which means that it’s only used when there are signs or symptoms of a Zika virus infection. Testing in patients with symptoms is only conducted if a patient has traveled to an area with a Zika virus outbreak.

What does the test measure?

There are several tests that may be used to detect a Zika virus infection. These tests look for the genetic material of the Zika virus or antibodies produced in response to a Zika virus infection. The choice of which test is ordered depends on the last possible exposure to the Zika virus and when a person began to experience symptoms.

Nucleic acid amplification testing (NAAT) looks for a type of genetic material from the Zika virus called RNA. NAAT is the preferred method of testing for a Zika virus infection in non-pregnant patients whose symptoms began within the previous seven days. A positive result is sufficient to confirm an infection without additional tests. A common type of NAAT used in diagnosing a Zika virus infection is a polymerase chain reaction (PCR) test. This type of test can be performed on a sample of blood or urine.

Antibody testing is another method of testing for a Zika virus infection. Antibodies are proteins made by the immune system to fight foreign substances such as the Zika virus. After becoming infected with the Zika virus, antibodies become detectable in the blood within the first week after symptoms begin and remain detectable for up to 12 weeks. In some cases, these antibodies may remain detectable for months to years. There are two types of antibody tests that may be used to diagnose a Zika virus infection, both performed using a blood sample:

  • Immunoglobulin M (IgM) testing: IgM antibody testing detects Zika-specific antibodies in the blood.
  • Plaque reduction neutralization test (PRNT) testing: PRNT testing detects a different type of antibody in the blood that neutralizes or inactivates the virus, called a neutralizing antibody.

When testing pregnant patients, both NAAT and antibody testing are performed simultaneously.

When should I get a Zika virus test?

According to the CDC, the number of reported cases of Zika virus infection worldwide is now very low and most people don’t need Zika virus testing. In fact, there have been no reported cases of Zika virus infection in the United States since 2019.

Doctors may recommend testing if patients are showing signs of an infection and have recently traveled to an area with a known Zika outbreak. Around 80% of individuals infected with Zika virus have no symptoms. When symptoms are present, they usually last from four to seven days and may include:

  • Fever
  • Rash
  • Conjunctivitis, also called pinkeye
  • Joint pain
  • Eye pain
  • Headache
  • Muscle pain

Many pregnant people are concerned about transmitting Zika virus to their fetus because ZIKV is known to cause microcephaly and other birth defects. Testing for a Zika virus infection before getting pregnant is not recommended. Zika virus testing is only recommended if a pregnant person:

  • Has symptoms and a history of travel to an area with a Zika outbreak
  • Has symptoms and has recently had sex with someone who lives in or has traveled to an area with a risk of Zika virus
  • Has an ultrasound that shows certain abnormalities that may be related to a Zika virus infection
  • Does not have symptoms, but lives or travels at least weekly to an area with known transmission of the Zika virus

Finding a Zika Virus Test

How to get tested

Zika virus testing is ordered by a doctor. Testing is conducted in a specialized laboratory that is approved to perform this complex type of testing.

Can I take the test at home?

There are currently no at-home tests available for detecting a Zika virus infection. This test needs to be conducted by a professional at a specialized laboratory.

How much does the test cost?

The cost of Zika virus testing depends on which tests are performed, the lab where the test is conducted, and your health insurance coverage. When Zika testing is ordered by your health care provider, the test may be covered by your health insurance. It may still be helpful to discuss the cost of testing with your health insurance company as you may be responsible for other out-of-pocket costs such as copays and deductibles.

If you don’t have health insurance or if your insurance doesn’t cover the cost of testing, it may be helpful to discuss the cost of Zika testing with a doctor or hospital administrator.

Taking a Zika Virus Test

Zika virus testing uses a sample of blood or urine. Rarely, amniotic fluid that surrounds the fetus may be collected from pregnant patients for testing.

Before the test

Before a Zika virus test, it’s important to inform your doctor if you have ever been diagnosed with Zika or another disease caused by Flaviviruses, including dengue infection, chikungunya disease, or yellow fever.

There is no special preparation required for a blood draw or urine collection.

During the test

To collect a sample for testing, a blood sample is taken with a needle inserted into a vein in your arm. Blood draws typically take just a few minutes. There are a number of steps to a blood draw that you might expect.

  • The health care provider taking your blood will use an alcohol wipe to disinfect your arm in the area where the needle is inserted. This is most often on the inside of the elbow.
  • A tourniquet is then tied around your upper arm to increase the blood pressure, which makes the vein more visible and easier to access with the needle.
  • A needle is inserted in your vein. This may cause a pinch or a little pain. A sample tube is attached to the needle and filled with blood. If the health care provider has ordered more tests to be done, there may be more than one tube used to collect blood samples.
  • After the test tube or vials are filled and the needle is removed.

Collecting a urine sample generally requires you to urinate in a cup. Your provider will offer specific instructions on how to properly collect urine for a Zika virus test.

After the test

After the blood draw is complete, a band-aid or cotton swab may be placed over the site where the needle was inserted to prevent bleeding. You may be instructed to keep this in place for an hour or more.

Once the blood draw is over you will be cleared to return to normal activities, including driving, though it is common that the health care provider will have you stay for 15 minutes or so to observe for any side effects. Common side effects after any blood draw are bruising, dizziness, or lightheadedness. If you notice any persistent pain, bleeding, or signs of infection, you should contact your doctor.

Zika Test Results

Receiving test results

How long it takes to receive Zika virus test results depends on the health care provider you worked with, the lab used, and the type of test performed. Receiving Zika virus test results may involve a follow-up appointment, a phone call, or an email from your doctor.

Interpreting test results

The results of a Zika virus test may be listed on a test report as either positive, negative, or inconclusive.

A positive test result means that traces of genetic material from the Zika virus or antibodies to the Zika virus were found in the test sample. Test results are interpreted based on which test was performed:

  • A positive test result on a NAAT test indicates that you probably have a Zika virus infection.
  • A positive test result on an IgM antibody test means that you may have a Zika virus infection, but follow-up PRNT testing is needed to confirm the result.

A negative test result indicates that no evidence of a Zika virus infection was found in your test sample. A negative test result may have several meanings depending on the specific test used, including:

  • A negative test result on a NAAT test indicates that you probably do not have a Zika virus infection, but this test is not able to definitively rule out a Zika virus infection. Follow-up antibody testing may be done to confirm a negative NAAT test result.
  • A negative test result on an IgM antibody test means that there is no evidence of a recent Zika virus infection.

If your test comes back as inconclusive it means that your test was not able to diagnose or rule out a Zika virus infection. Your health care provider will likely have you come back for more testing.

If you have any questions about your test results, your doctor is in the best position to review your test report, explain what it means for your health, and determine if any follow-up tests are necessary.

Are test results accurate?

Zika virus tests are authorized by the FDA to diagnose or rule out a Zika virus infection. In order to ensure the accuracy of test results, medical professionals follow established guidelines for the specific circumstances in which testing is appropriate.

False negative test results, in which a person has a negative test result despite having a Zika virus infection, can occur due to being tested too soon after infection. For example, antibodies may not be found on an IgM antibody test until around a week after symptoms of an infection begin.

False positive results occur when a test result is positive for a Zika virus infection when a patient does not actually have this infection. These results may occur when using an IgM antibody test, which may not distinguish between a Zika virus infection and an infection caused by other Flaviviruses. This is why a PRNT test specific for Zika neutralizing antibodies is always used to confirm a positive IgM antibody test result.

Do I need follow-up tests?

Depending on the results of your Zika virus test, it is possible that your doctor will order follow-up tests to confirm your infection status. Follow-up tests depend on the type of Zika virus test performed and the length of time since your symptoms began:

  • Positive NAAT test results are sufficient to diagnose a Zika virus infection in patients who are tested within seven days of the onset of symptoms and a history of possible exposure. No additional follow-up testing is needed.
  • Negative NAAT test results may require follow-up antibody testing
  • Positive IgM test results require additional confirmatory PRNT testing
  • Negative IgM test results usually do not require follow-up testing unless there is a concern that the blood sample was collected too early in the infection

Refer to your doctor for questions about follow-up testing and whether it is appropriate for you.

There are no FDA-approved vaccines or treatment for ZIKV at this time.

Questions for your doctor about test results

It can be helpful to discuss questions with your doctor about your Zika virus test results. Helpful questions may include:

  • What type of Zika virus test was performed?
  • Do I need any follow-up tests based on my test result?
  • How does my test result help me understand the cause of my symptoms?
  • Is it possible that I have another Flavivirus?

Zika virus testing for fetuses and newborns

Testing for Zika virus infection in fetuses during pregnancy may be considered if ultrasound findings suggest abnormalities that could be caused by a Zika virus infection. Testing of a fetus may also be recommended if the pregnant parent has a positive or inconclusive Zika virus test result.

To determine if a fetus has a Zika virus infection, amniotic fluid may be extracted during a process called amniocentesis.

After birth, Zika virus testing may be recommended for infants in several situations, including:

  • Infants born to a parent who is diagnosed with a Zika virus infection
  • Infants who have signs or symptoms that may be caused by a Zika virus infection

Test samples used to detect a Zika virus infection in infants include cerebrospinal fluid (CSF), a liquid found in the brain and spinal cord.

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