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A toxoplasmosis test is a blood test that checks for antibodies to the Toxoplasma gondiiparasite. Your body's natural defence 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.
A toxoplasmosis test is done to check if a:
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.
The health professional taking a sample of your blood will:
The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.
There is very little chance of problems from having blood drawn from a vein. You may get a small bruise at the site. You can lower your chance of bruising by keeping pressure on the site for several minutes.
In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. You can use a warm compress several times a day to treat this.
A toxoplasmosis test is a blood test that checks for antibodies to the Toxoplasma gondii parasite. The results of the test are usually given in titres. A titre is a measure of how much the blood sample can be diluted with a saltwater solution (saline) before the antibodies can no longer be found. Test results are usually ready in 1 to 3 days.
A titre of 1 to 8 (1:8) means that antibodies can be found when 1 part of the blood sample is diluted by up to 8 parts of a saltwater solution (saline). A larger second number means there are more antibodies in the blood. So a titre of 1 to 128 means there are more toxoplasmosis antibodies in the blood than a titre of 1 to 32.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range that your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
IgM in babies:
IgM in adults:
Less than 1:64
Less than 1:1024
Toxoplasmosis antibodies usually form within 2 weeks after being infected. The titre is the highest 1 to 2 months after infection.
Other infections can cause a false-positive result in a newborn.
Other antibodies, such as rheumatoid factor or antinuclear antibodies, may also cause a false-positive result.
To learn more about toxoplasmosis infection in pregnancy, see the topic Toxoplasmosis During Pregnancy.
CitationsChernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.Other Works ConsultedFischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
Current as of: February 11, 2020
Author: Healthwise StaffMedical Review: Sarah Marshall MD - Family MedicineBrian D. O'Brien MD - Internal MedicineE. Gregory Thompson MD - Internal MedicineAdam Husney MD - Family MedicineKathleen Romito MD - Family MedicineKirtly Jones MD - Obstetrics and Gynecology
Current as of: February 11, 2020
Author: Healthwise Staff
Medical Review:Sarah Marshall MD - Family Medicine & Brian D. O'Brien MD - Internal Medicine & E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine & Kathleen Romito MD - Family Medicine & Kirtly Jones MD - Obstetrics and Gynecology
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