Prevalencia de anticuerpos contra el Trypanosoma cruzi en donantes de sangre de la Seguridad Social- Costa Rica, Setiembre 2003 - Setiembre 2004.

the chagas？s disease is a infection caused by trypanosoma cruzi parasite; it is responsible of infestation of 16 to 18 people in latin america with 50,000 deaths every year. the main source of transmission is for blood transfusion. since september 2003, caja costarricense de seguro social？s blood banks have implemented the screen in about 100% of donors of the country. the 53307 serum samples were collected in the period of september 2003 to september 2004, and they were tested with the eia with three types of antigenic sources (recombinant protein, homolog peptides, protein lysate of strain brenner for wb). of the tested samples, 305 (0.6%) were beginning reactives. of these, 176 (58%) were repeat reactives (rr) for the test eia-icmrt. of the rr, 122 (69%) shown discrepancy between two eia tested, 42 (24%) were positives for the two assays and 12 (7%) did not have be evaluated. the rr samples tested for eia-icmrt, 39 (22%) were positives for wb, 65 (37%) were indetermined, 56 (32%) were negatives, and 15 samples stayed pending. the results of the study got 0.6% of initial positive test; it was a light increment with respect to results of the 3 years in the country. the prevalence was 0.08%, it is the lowest in central america. comparing the results between eia-icmrt and wb, it was a bigger correlation between the samples with do highs >2, 0 and a positive result for wb according the established criterion. in general, the negative or indeterminate results for wb correspond to samples with do<2, 0 and against proteins with low molecular weights (15-50 kd). the study shown the importance to do certain diagnostic assays of high sensibility and specificity for determine the real prevalence and for the control of transmission of infection with the proposal of offer blood banks to costarican people and rational use of them.