[Detection of IgM against the dengue++ virus in whole blood absorbed on filter paper]

This paper presents a standardized procedure for the detection of IgM antibodies to dengue virus in blood samples taken from filter paper. The samples were obtained from 118 patients, of whom 91 had been clinically diagnosed with dengue and 27 with a viral infection unrelated to that disease. The first group of patients came from Costa Rica and Nicaragua and the second group from Cuba. All the samples were tested for IgM antibody against dengue virus by means of a capture enzyme immunoassay (EIA). Analysis of the results for patients from all three countries together yielded a sensitivity of 98.1% and a specificity of 98.5% for the test done on whole blood on filter paper stored at 4 degrees C; agreement between the results of that test and those of the EIA using serum samples was 96%. In a comparison of the results obtained with three samples from the same patient--whole blood on filter paper stored at room temperature, the same type of sample stored at 4 degrees C, and serum--the agreement was 86%. This study demonstrates the high diagnostic sensitivity and specificity achieved when whole blood absorbed on filter paper is processed in the manner described in detail in the article. The authors recommend the use of this method in the dengue surveillance programs in the Region.