Misdiagnosis of toxoplasma infection by PCR: fears unfounded

A nested PCR based diagnostic assay for the detection of toxoplasmosis was devised in 1990 and was used successfully among a battery of tests for the clinical diagnosis of Toxoplasma gondii infection since 1991. However, it w as reported that the assay produced false positive diagnoses with Nocardia asteroides infection. Investigation of this phenomenon showed that although cross reactivity with some unrelated organisms may be observed when altere d conditions are employed, the assay does not lead to misdiagnosis if perfo rmed under the appropriate, stringent conditions.