Does this test have other names?

Immunoglobulin G antibodies, immunoglobulin M antibodies, Sabin-Feldman dye test, IFA test, EIA test

What is this test?

This test looks for antibodies against Toxoplasma gondii (T. gondii) infection in your blood.

T. gondii is a parasite that can infect people when they:

• Eat infected meat, especially lamb, venison, or pork, that hasn't been fully cooked.

• Eat food contaminated by knives, utensils, cutting boards, or other foods that have come in contact with the 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. But in people whose immune system isn't working well, a T. gondii infection can cause brain damage and other serious problems. If you're pregnant and are infected, it can cause stillbirth, severe birth defects, or problems that can be seen in the child years later.

Why do you need this test?

You may need this test if your doctor thinks that you have toxoplasmosis. Most people who are infected with T. gondii don’t know it. Symptoms can include:

• Flu-like symptoms, such as achiness and swollen lymph nodes.

• Blurry vision, eye redness, and pain if the disease is affecting the eyes.

A small number of infected infants have brain or eye damage at birth.

If you're pregnant, you may also have this test, especially if you may have been exposed to T. gondii.

What do your test results mean?

Test results may vary depending on your age, sex, and health history. Your test results may also vary depending on the lab used. Ask your doctor what your test results mean for you.

Test results can show if you have higher levels of immunoglobulin G (IgG) or immunoglobulin M (IgM) antibodies that are related to T. gondii infection. IgM antibodies tend to show up faster and go away faster after an infection. IgG antibodies tend to slowly go away over the next 1 to 2 years.

The results can tell your doctor if you have a new infection or had an infection in the past.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

What might affect your test results?

If you have AIDS and toxoplasmosis, you may have only a small rise in IgG. In this case, the results for IgM and other antibodies may show up as negative. Other factors aren't likely to affect your results.

How do you get ready for this test?

Tell your doctor if you have a condition that affects your immune system or if you are taking any medicines that may do so. Be sure your doctor knows about all the medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.