Evaluation of the Toxocell Latex Agglutination Test as Screening Test and Distribution of Toxoplasma Antibodies among Sexually Active People in Najaf City

Abstract

Objectives: The present study was intended to reveal the validity of Toxocell (Biokit, Spain) latex agglutination test as screening test. The rate of toxoplasma antibodies distribution in randomly selected subjects was estimated. The sensitivity and specificity of the test were conducted in comparison to the "gold standard" reference test Enzyme-linked Immunosorbent Assay (ELISA, BioCheck, Inc).

Methodology: Fifty two adult persons (31 females and 21 males) were enrolled in this study. Twenty (38.4%) serum samples out of 52 subjects were positive for toxoplasma antibodies by direct latex agglutination test (DLA). The prevalence of toxoplasma antibodies in females and males were 54.8% and 14.28%, respectively. Among twenty DLA sera positive, only 5(25%) serum samples were positive with toxoplasma IgG ELISA test, three females and two males. However, the results of IgM ELISA assay were positive for only two (10%) female serum samples. None of negative DLA serum samples gave positive results with neither IgG nor IgM ELISA assay.

Results: The sensitivity and specificity and positive predictive value (PPV) of DLA test ( in comparison to IgM ELISA assay) were 100%, 64% and 10%, respectively. We concluded that in spite of low specificity of latex agglutination test, it was probably more suitable for laboratories in remote area as screening test where ELISA facility was unavailable.