Retrospective Evaluation of Serologic and Molecular Test Results of Toxoplasmosis Suspected Patients

Toxoplasma gondii is a compulsory intracellular protozoan parasite with a wide range of host in warm-blooded vertebrates and has importance in terms of health and economy. Toxoplasmosis is very common because it can infect people with a variety of ways; ingestion of contaminated water and nutrients; raw or undercooked meats containing tissue cysts, blood transfusions, organ transplantantation and transplacental transfer. The aim of this study was to evaluate serologic and molecular test results of toxoplasmosis pre-diagnosed patients. Anti-T.gondii-IgG, anti-T.gondii-IgM ELISA, anti-T.gondii-IgM IFAT and anti- T.gondii-IgG avidity serological tests and PCR tests were applied by using blood, cerebrospinal fluid, amniotic fluid, pericardial fluid and abscess samples from patients who have admitted to Erciyes University Faculty of Medicine Department of Parasitology routine serology and molecular diagnosis laboratories with a pre-diagnosis of toxoplasmosis. Among 6547 patients 3.3% (n= 220) were only IgM positive, 9.2% were both IgG and IgM positive (n= 598). Among male patients, the positivity rates were lower and only IgM seropositive patients were 0.6% (n= 45) while the frequency of both IgG and IgM positive patients was 0.8% (n= 47). The number of both IgG and IgM seropositive cases among new borns, constituting 6.4% (n= 425) of the total number of patients, was 20 (0.3%) and the number of IgM seropositive samples was 25 (0.4%). Only 290 patients positive for IgM antibodies were studied for IFAT and 22 of these patients were positive for anti-T.gondii-IFAT IgM. Anti- T.gondii IgG avidity test was performed in all IgG positive patients regardless of their IgM seropositivity; low avidity was found in 0.7% (n= 18) of IgM-negative patients' sera and equivocal avidity was detected in 6.5% (n= 179). Low avidity was detected in 2.6% of IgM positive patients. Nine of the patients evaluated as anti-T.gondii IgM negative and IgG positive were detected as positive by PCR and two of them were negative. One of these PCR-positive patient's amniotic fluid was sent after the serological test results and detected as positive. Twenty CSF samples were studied by PCR and 7 samples were positive. Also, 8 blood samples which were anti-T.gondii IgM negative and IgG positive were found to bepositive in 7 and negative in one sample with PCR results, subsequently. PCR tests with pericardial fluid and abscess materials were found to be negative. In the case of suspicious or risky situations such as false negatives or false positives resulting from cross-reaction that can occur in ELISA tests, unnecessary medication or interventional approaches can be avoided by applying molecular-based testing at laboratories with appropriate infrastructure. For this reason, we believe that the application of molecular tests in addition to serological tests in risky situations may give more reliable results