Toxoplasma infection: Making the best use of laboratory tests

Toxoplasma gondii is a parasite found worldwide that commonly causes nonpathologic infections in humans; however, infection may be harmful in certain persons. In the United States, infection occurs mainly from the ingestion of undercooked meat containing the cyst form of the parasite. The serologic diagnosis can be complex. To address this, a panel of antibody tests has been designed to determine whether infection with T gondii is recent or remote. The polymerase chain reaction assay to diagnose infection with Toxoplasma has high utility in specific clinical scenarios, such as prenatal diagnosis and diagnosis in immunocompromised patients.