Toxoplasma Gondii (Amniotic Fluid)

Does this test have other names?

Polymerase chain reaction (PCR) for Toxoplasma gondii DNA

What is this test?

This test is used to diagnose Toxoplasma gondii (T. gondii) infection in a baby in the womb. T. gondii is a parasite. This test looks for the parasite in the amniotic fluid around your baby.

People can become infected with the parasite when they:

  • Eat infected meat that hasn't been fully cooked, such as lamb, venison, pork, or shellfish (oysters, clams, mussels)

  • Eat food contaminated by knives, utensils, cutting boards, or other foods that have come in contact with infected meat

  • Drink contaminated water

  • Swallow the parasite after being exposed to it while cleaning an infected cat's litter box

In healthy adults, this infection often doesn’t cause any symptoms. T. gondii may be a problem if a person is infected with the parasite for the first time while pregnant. The parasite can travel to their unborn baby. This can lead to birth defects, such as brain damage and serious eye problems. Children who seem unaffected at birth may still have problems later in life. People who are infected before they become pregnant only rarely pass the disease to their unborn babies.

Why do I need this test?

You may need this test if you're pregnant and your healthcare provider thinks that you have a new T. gondii infection. The results can help guide treatments that may help keep your baby from having health problems.

What other tests might I have along with this test?

Your healthcare provider may want to test you for antibodies called IgM and IgG. Your immune system makes these to fight this parasite. These tests can show if you have been infected during pregnancy. Your blood may also be tested to look for the parasite.

You may also have an imaging test, such as a CT scan or ultrasound. This is done to examine your baby in the womb. 

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

If your results are negative, you and your baby don't have the parasite. A positive result means that you and your baby have the parasite.

How is this test done?

This test is done by taking a sample of the amniotic fluid that surrounds your baby in the womb. This is done with an amniocentesis. Using ultrasound as a guide, your healthcare provider will put a long, thin needle into your belly (abdomen) and into the womb (uterus). They will take a small sample of amniotic fluid to be tested.

Does this test pose any risks?

Risks from the amniocentesis procedure include:

  • Cramping and discomfort

  • Vaginal bleeding

  • Injury to the baby

  • Leakage of amniotic fluid

  • Miscarriage, which can occur in about 1 in every 300 to 500 procedures

  • Risk of an existing chronic infection you have, such as hepatitis or HIV, infecting your baby 

What might affect my test results?

This test will not find T. gondii DNA in amniotic fluid if you develop antibodies against the parasite during your first trimester.

How do I get ready for this test?

Ask your healthcare provider if you should take any special steps to prepare for this test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don’t need a prescription and any illegal drugs you may use.  

Online Medical Reviewer: Chad Haldeman-Englert MD
Online Medical Reviewer: Raymond Turley Jr PA-C
Online Medical Reviewer: Tara Novick BSN MSN
Date Last Reviewed: 10/1/2022
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