Comparison of the indirect immunofluorescent antibody test and the direct agglutination test for serodiagnosis of visceral leishmaniasis in HIV-infected subjects.

One hundred subjects positive for anti-human immunodeficiency virus (HIV) antibodies were tested for anti-Leishmania antibodies by the indirect immunofluorescent antibody test (IFAT) and the direct agglutination test (DAT). Subjects were subsequently followed for two years to monitor the onset of visceral leishmaniasis. Fifteen subjects were positive for anti-Leishmania antibodies in either one or both tests. Eleven were positive only by IFAT, one only by DAT, and three by both tests. During the two-year follow-up period, nine subjects developed visceral leishmaniasis; of these, six were serologically positive, four by IFAT alone and two by both tests. The results indicate that IFAT and DAT have a similar specificity but that IFAT has a higher sensitivity and a greater diagnostic significance.