[Serologic diagnosis of Lyme disease. A pending problem]

We analyze the experience in serologic diagnosis of Lyme's borreliosis. From a total of 551 patients studied from 1987 to 1989, we further evaluate 80 cases with erythema chronicum migrans or a clinical diagnosis of Lyme's disease and positive serological tests. The techniques used were IFI, ELISA1 (Whittaker Bioproducts) and ELISA2 (MarDx Diagnostics). Serological tests results were evaluated in relation to clinical data. Five cases were excluded because of no-specific symptoms. There were 20 false-positive results, mainly due to other infections (HIV infection, tuberculosis, Mediterranean spotted fever and syphilis). Fifty-five patients were considered clinically of having Lyme's disease. IFI test was positive in 81.8% of all the 55 cases, ELISA2 in 58.4% of 53 cases tested and ELISA1 in 23% of 43 cases tested. Correlation between IFI and ELISA2 positive test was seen in 45% of cases. Specificity of all tests was higher than 97%. The study shows that sensitivity for all three techniques used was not optimal, and also there are some differences in their results. However, specificity was adequate.