Abstract

TORRES, Elizabeth et al. Validation of anti-Toxoplasma IgM ELISA tests in newborn screening programs. Infect. [online]. 2011, vol.15, n.2, pp.84-91. ISSN 0123-9392.

Objectives: To evaluate and validate the detection of anti-Toxoplasma IgM ELISA in umbilical cord blood by means of two different commercialassays and to correlate the results with the diagnosis of congenital infection in children by serological follow up and clinical data. Materials and methods: We evaluated the commercial anti-Toxoplasma IgM ELISA kitÔ from Vircell (Granada, Spain) compared to the results of Toxoplasma IgM Western blotÔ (LDbio, Lyon, France) and IgM ELISA testÔ from Labsystems (Finland). We obtained the receptor-operator curve (ROC) for the IgMELISA assay form Vircell and Labsystems. We studied 105 umbilical cord blood serum samples from Colombian children from six different cities by Westernblot, and clinical and serological follow up for positive cases. The kappa agreement index was determined for the 105 sera obtained from umbilical cords. Results: The Vircell assay showed a better performance with a cut-off index of 8 against a 16 for Labsystems for enzyme immunounits (EUI). Whenthe results were evaluated against the Western blot assay, the Vircell IgM assay had a sensitivity of 100% (IC95%: 71.8-100) and a specificity of 78%(IC95%: 69-85.7), the IgM assay from Labsystems had a sensitivity of 100% (IC95%; 71.8-100) and a specificity of 100% (IC95%; 96-100). Agreement between both tests (Labsystems and Vircell) was 80% and had a kappa index of 0.45. Conclusions: A cut-off point of 8 for the anti-Toxoplasma IgM ELISA assay from Vircell and 16 EIU for the Labsystems assay allow the identificationof congenital infections in umbilical cord blood samples from Colombian children.

Keywords : Toxoplasmosis [diagnosis]; ELISA; Western blot; ROC curve; sensitivity; specificity; newborn; umbilical cord; screening.

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