COMPARISON OF TWO FULLY AUTOMATED IMMUNOASSAYS: ELISA (CHORUS) AND ELFA

Toxoplasma gondii is a parasitic protozoa which can be transmitted by eating infected meat or from mother to fetus during the first trimester of pregnancy. This microscopic parasit can cause fetal infection with unpredictable consequences in later life. Medical diagnostic is working to determine the most sensitive techniques for the detection of T. gondii antibodies, in the framework of which is developed this scientific work. An enzyme-linked immunosorbent assay (ELISA, applied in CHORUS instrument) and an enzyme-linked fluorescent assay (ELFA, applied in Mini-Vidas instrument) have been compared with each other for the detection of Toxoplasma IgM antibodies. There have been analyzed 200 patients with each technique. 189 out of 200 samples (94,5%), gave compatible results. In particular, 155 samples gave negative results, 31 samples gave positive results and 3 samples gave doubtful results with both techniques. It was observed that 11 samples were positive in Vidas instrument and doubtful in Chorus instrument. Comparative evaluation of the two assays demonstrated a comparable sensitivity for all systems. ELFA technique showed a better ability to detect Toxoplasma IgM antibodies during the early stage of acute infection. Analysis of the results revealed a good level of concordance between the two assays and confirmed the usefulness of ELFA technique to diagnose acute toxoplasmosis.