Toxoplasmosis Test: Results

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Results

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 titers. A titer 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 titer 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 titer of 1 to 128 means there are more toxoplasmosis antibodies in the blood than a titer of 1 to 32.

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

• If high titers of the IgM type of antibody are found, it means the infection is recent. If high titers 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 titers that do not get higher usually mean the infection occurred in the past. Once you have had toxoplasmosis, you cannot be infected again.

Last updated:	June 27, 2007
Author:	Maria G. Essig, MS, ELS
Reviewed By:	Joy Melnikow, MD, MPH - Family Medicine, Gregory A L Davies, MD, FRCSC, FACOG - Maternal-Fetal Medicine
Editors:	Susan Van Houten, RN, BSN, MBA, Tracy Landauer