Toxoplasmosis Test

Results

A toxoplasmosis test is a blood test that checks for antibodies to the Toxoplasma gondiiparasite. 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 salt water 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 salt water 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.

Normal titres

Antibody	Titre
IgM in babies:	Less than 1:2
IgM in adults:	Less than 1:8
IgG:	Less than 1:16

Toxoplasmosis antibodies usually form within 2 weeks after being infected. The titre is the highest 1 to 2 months after infection.

• If high titres of the IgM type of antibody are found, it means the infection is recent. If high titres of the IgG type of antibody are present, it means an infection occurred in the past.
• Blood samples may be taken over several weeks to see if the number of antibodies is getting higher. This would mean the infection is recent.
• Low titres that do not get higher usually mean the infection occurred in the past. Once you have had toxoplasmosis, you cannot be infected again.

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Author:	Maria G. Essig, MS, ELS Ralph Poore	Last Updated: August 17, 2007
Medical Review:	Joy Melnikow, MD, MPH - Family Medicine Gregory A L Davies, MD, FRCSC, FACOG - Maternal-Fetal Medicine
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