The toxoplasma test looks for antibodies in the blood to a parasite called Toxoplasma gondii. The parasite causes an infection called toxoplasmosis, which poses a danger to a developing baby if a pregnant women gets it. It is also dangerous in people with AIDS.
Toxoplasma serology; Toxoplasma antibody titer
A blood sample is needed. For information on how this is done, see: Venipuncture
The sample is sent to a lab, where antibodies to Toxoplasma gondii are detected using several tests, including an indirect fluorescent antibody test, ELISA, and the Sabin-Feldman dye test.
There is no special preparation for the test.
When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.
The test is done soon after pregnancy to detect toxoplasmosis infection in a newborn baby. It may also be used to screen pregnant women for the antibodies to the parasite.
The presence of antibodies before pregnancy probably protects a developing baby against toxoplasmosis at birth. However, antibodies that develop during pregnancy may mean the mother and baby are infected. This increases the risk of miscarriage or birth defects.
This test may also be done if you have:
A titer (measurement of the concentration in a sample) of less than 1:16 indicates that there has likely never been an infection with toxoplasma gondii.
A titer of 1:16 - 1:256 is a sign that you have probably been infected with the parasite sometime in the past.
A titer of greater than 1:1,024 may be a sign of an active toxoplasmosis infection.
The examples above are common measurements for results of these tests. 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:
Liesenfeld O. Toxoplasmosis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap XX. Toxoplasmosis
Montoya JG, Boothroyd JC, Kovacs JA. Toxoplasma gondii. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 279.