Food Poisoning Health Center

A toxoplasmosis test is a blood test that checks for antibodies to the Toxoplasma gondiiparasite. Your body's natural defense system (immune system) will make these antibodies only if you have been infected by this tiny parasite. The amount and type of antibodies you have shows whether your infection is recent or occurred in the past. More than one blood test may be done over several weeks.

For most people, toxoplasmosis is not dangerous and goes away on its own. But if a pregnant woman becomes infected and passes it on to her growing baby (fetus), it can cause blindness and brain damage in the fetus.

You can become infected by eating food such as undercooked or raw meat from an infected animal or by handling an infected cat or its stool (feces). After you have been infected, you will have antibodies to Toxoplasma gondii for the rest of your life, so you cannot be infected again.

To see if your growing baby is infected, the test can be done on a sample of the fluid that is around your baby (amniotic fluid) taken during amniocentesis.

Why It Is Done

A toxoplasmosis test is done to check if a:

• Pregnant woman has antibodies from a toxoplasmosis infection. If she has the IgG type of antibody, that means an infection occurred in the past and the baby does not have a chance of becoming infected. If she has the IgM type of antibody, that means the infection is recent and the baby does have a chance of becoming infected.
• Baby has toxoplasmosis.
• Person with a weakened immune system, such as someone who has HIV, has a chance of getting a toxoplasmosis infection.

How To Prepare

Tell your doctor if you are pregnant and have contact with a cat or clean a cat's litter box. Before your blood is drawn, let your doctor know if you have bleeding or clotting problems, or if you take blood-thinning medicine.

You do not need to do anything else before you have this test.

How It Is Done

The health professional taking a sample of your blood will:

• Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed.
• Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Apply a gauze pad or cotton ball over the needle site as the needle is removed.
• Apply pressure to the site and then a bandage.