Validity of a new immunochromatographic test in detection of Toxoplasma gondii in cancer patients

Abstract

Screening of toxoplasmosis in cancer patients is mandatory especially before starting treatment to guard against life-threatening disseminated disease. Diagnosis of toxoplasmosis rely mainly on serology. The most widely used method for detection of anti- Toxoplasma gondii ( T. gondii) antibodies is the enzyme linked immunosorbent assay (ELISA), being available and reliable. Immunochromatographic tests (ICT) attracted a lot of attention recently being one of the high quality, rapid and easy to perform tests. Available data comparing the performance of ICT versus ELISA techniques have yielded inconsistent results and none compared their performance among the immunocompromised cancer patients. Therefore, we designed this study to compare the performance of a new ICT (the OnSite Toxo IgG/IgM Combo Rapid test) and ELISA techniques for the detection of anti- T. gondii antibody as a tool for screening for toxoplasmosis among cancer patients in Cairo-Egypt. Among 180 cancer patients, a total of 110 patients (61.1%) were positive for anti- T. gondii antibodies by one or both methods. Agreement between both methods was found in 78.8% of the samples. By using ELISA technique as a gold standard test for the detection of anti- T. gondii antibodies, our results showed 87.5% specificity and 74% sensitivity of ICT technique. Moreover, our results proved that ICT is more sensitive in detecting lower level of antibodies than ELISA, that makes it preferable as a screening test for the immunocompromised patients.