Immunodiagnosis of Trypanosoma cruzi infection in humans using ELISA on blood collected on filter paper

Abstract

Seroepidemiological studies for the detection of Trypanosoma cruziantibodies require a great number of samples; their collection through venous puncture and transport is difficult. Collection of blood on filter paper significantly reduces these problems to a minimum. This study assessed this system as well as the validity and reproducibility of the enzyme immunoassay (ELISA) for the diagnosis of Trypanosoma cruzi human infection. Serum samples and blood eluates collected on filter paper (taken from people living in zones where Chagas'disease is considered to be endemic) were tested for Trypanosoma cruzi antibodies by using the immunofluorescent antibody test (IFAT) and ELISA. The validity of ELlSA using blood eluates collected on filter paper showed an area under the receptor-operator curve (ROC) of 0.944.The agreement between both kinds of samples in the ELlSA test showed a near to normal distribution with an average of -0.01 and a standard deviation of 0.23. The reproducibility of the IFAT test was shown to be lower than that for the ELlSA test. Its greater concordance, sensibility and specificity make the ELlSA test a good alternative to the Trypanosoma cruz; antibody detection reference tests and for use in seroepidemiological surveys.