The toxoplasma test looks for antibodies in the blood to a parasite called Toxoplasma gondii. The parasite causes an infection called toxoplasmosis. The infection is a danger to a developing baby if a pregnant woman gets it. It is also dangerous in people with AIDS.
Toxoplasma serology; Toxoplasma antibody titer
How the Test is Performed
A blood sample is needed.
How to Prepare for the Test
There is no special preparation for the test.
How the Test Will Feel
When the needle is inserted to draw blood, some people may feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or a slight bruise. These soon go away.
Why the Test is Performed
The test is done when the health care provider suspects that you have toxoplasmosis.
In pregnant women, the test is done to:
- Check if a woman has a current infection or had an infection in the past.
- Check if the baby has the infection.
The presence of antibodies before pregnancy probably protects a developing baby against toxoplasmosis at birth. But antibodies that develop during pregnancy may mean the mother and baby are infected. This infection during pregnancy increases the risk of miscarriage or birth defects.
This test may also be done if you have:
- Unexplained lymph node swelling
- An unexplained rise in the blood white cell (lymphocyte) count
- HIV and have symptoms of a toxoplasmosis of the brain (including headache, seizures, weakness, and speech or vision problems)
- Inflammation of the back part of the eye (chorioretinitis)
Normal results mean you have likely never had a toxoplasma infection.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test result.
What Abnormal Results Mean
Abnormal results mean that you have probably been infected with the parasite. Two types of antibodies are measured, IgM and IgG:
- If level of IgM antibodies are raised, you likely became infected in the recent past.
- If level of IgG antibodies are raised, you became infected sometime in the past.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Duff P. Maternal and perinatal infection - bacterial. In: Gabbe SG, Niebyl JR, Simpson JL, et al., eds. Obstetrics: Normal and Problem Pregnancies. 6th ed. Philadelphia, Pa: Elsevier Saunders; 2012:chap 51.
Montoya JG, Boothroyd JC, Kovacs JA. Toxoplasma gondii. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 279.
Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.