What is a Zika virus test?

A Zika virus test looks for signs of the Zika infection in your blood or urine. Zika is a type of flavivirus, as is dengue fever and West Nile. Like those viral infections, Zika is usually spread by mosquitoes, especially in areas with tropical climates, such as parts of Central and South America, Africa, Mexico, and islands in the Caribbean and Pacific. Because Zika can enter bodily fluids such as blood, urine (pee), and semen, it can also spread through sex with an infected person or from a pregnant woman to her fetus.

There are two types of tests used to check for Zika infections:

• Molecular tests. These tests look for genetic material from the Zika virus. The tests are also called nucleic acid amplification tests (NAAT or NAT). A PCR test (polymerase chain reaction) is a common type of molecular test that checks for the Zika virus in a sample of your blood or urine. This test is recommended if you're pregnant.
• Antibody tests. Antibodies are proteins that your immune system makes to fight viruses and other germs. A Zika antibody test checks a sample of your blood for the antibodies that fight Zika. Your body needs time to make antibodies. So, to be accurate, an antibody test can be done starting within a week after symptoms begin.

Zika virus outbreaks tend to come and go. The recommendations for Zika testing are likely to change as outbreaks develop and disappear. Even without confirmed cases of Zika in the U.S., it is still possible to get the infection.

Other names: Zika Antibody Test, Zika RT-PCR Test, Zika test

What is it used for?

A Zika virus test is used to check for a Zika virus infection. It's mostly used on pregnant women who have recently traveled to an area where there is a risk of Zika infection. This is because a Zika infection can cause serious health problems for a fetus, including:

• Microcephaly, a birth defect that severely affects the development of a fetus' brain.
• Cerebral palsy, a condition that affects coordination and the ability to control one's muscles.
• Brain development issues.
• Vision or hearing problems.
• Low birth weight.
• Congenital Zika syndrome, a combination of conditions at birth, including microcephaly, a partially collapsed skull, and eye damage.

Zika infections during pregnancy have also been linked to an increased risk of miscarriage and stillbirth.

In rare cases, children and adults infected with Zika may get a disease called Guillain-Barré syndrome (GBS). GBS is a disorder that causes the body's immune system to attack part of the nervous system. GBS is serious, but treatable. With proper care, most people recover from GBS over time.

Why do I need a Zika virus test?

You may need a Zika virus test if you are pregnant and have recently traveled to an area where there is a risk of Zika infection. You may also need a Zika test if you are pregnant and have had sex with a partner who traveled to one of these areas.

A Zika test might be ordered if you have symptoms of Zika. Most people with Zika don't have symptoms, but when there are symptoms, they often include:

• Fever.
• Rash.
• Joint pain.
• Muscle pain.
• Headache.
• Red eyes (pink eye, also called conjunctivitis).

What happens during a Zika virus test?

A Zika virus test is usually a blood test or a urine test.

If you are getting a Zika blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

If you are getting a Zika urine test, a health care professional may give you a cleansing wipe, a small container, and instructions for how to use the "clean catch" method to collect your urine sample. It's important to follow these instructions so that germs from your skin don't get into the sample:

1. Wash your hands with soap and water and dry them.
2. Open the container without touching the inside.
3. Clean your genital area with the cleansing wipe:
   • For a penis, wipe the entire head (end) of the penis. If you have a foreskin, pull it back first.
   • For a vagina, separate the labia (the folds of skin around the vagina) and wipe the inner sides from front to back.
4. Urinate into the toilet for a few seconds and then stop the flow. Start urinating again, this time into the container. Don't let the container touch your body.
5. Collect at least an ounce or two of urine into the container. The container should have markings to show how much urine is needed.
6. Finish urinating into the toilet.
7. Put the cap on the container and return it as instructed.

If you have hemorrhoids that bleed or are having your menstrual period, tell your provider before your test.

If you are pregnant and your prenatal ultrasound shows the possibility of microcephaly, your health care provider may recommend a procedure called amniocentesis to check for Zika. Amniocentesis is a test that looks at the fluid that surrounds the fetus (amniotic fluid). For this test, your provider will insert a special hollow needle into your belly and withdraw a small sample of fluid for testing.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a Zika virus test.

Are there any risks to the test?

• There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
• There are no known risks to a urine test.
• Amniocentesis may cause some cramping or pain in your belly. There is a small chance the procedure will cause a miscarriage. Talk to your provider about the benefits and risks of this test.

What do the results mean?

• A positive Zika test result means you probably have a Zika infection.
• A negative result can mean that you aren't infected or that you were tested too soon for the virus to show up in testing. If you think you were exposed to the virus, talk to your provider about when or if you need to be retested.

If you are diagnosed with Zika and are pregnant, you can start to prepare for your baby's possible health problems before they are born. While Zika exposure doesn't always cause birth defects or health problems, many children born with Zika have long-lasting special needs. Talk to your provider about how to get support and health care services should you need them. Early intervention may make a difference in your child's health and quality of life.

If you are diagnosed with Zika and are not pregnant, but would like to become pregnant in the future, talk to your provider. They can tell you how long you should wait before trying to have a baby and if you need to be retested.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about a Zika virus test?

If you are pregnant or planning to become pregnant, you should take steps to reduce your risk of getting a Zika infection. The Centers for Disease Control and Prevention (CDC) recommends that pregnant women and their partners avoid traveling in areas that may put them at risk for Zika infection. If you can't avoid travel or if you live in one of these areas, you should:

• Apply an insect repellent containing DEET on your skin and clothing. DEET is safe and effective for pregnant women.
• Wear long-sleeved shirts and pants.
• Use screens on windows and doors.
• Sleep under a mosquito net.

If you or your partner think either of you have been exposed to Zika, use a condom during vaginal, anal, and oral sex. This step can greatly reduce your chance of getting or spreading the infection through sexual contact.