In this study, 60 persons with seroindeterminate results for HTLV were followed until their serological status was defined. Thus, Western blotting can be used to increase the specificity of serologic testing in Lyme disease. The high proportion of indeterminate results of the screening test for human T-lymphotropic virus (HTLV) infection has been a challenge worldwide. Among patients with indeterminate IgG responses by ELISA, 6 of 9 patients with active Lyme disease had positive blots compared with 2 of 34 patients with other illnesses (P <. When these definitions were tested in a prospective study of all 237 patients seen in a diagnostic Lyme disease clinic during a 1-year period and in 74 patients with erythema migrans or summer flu-like illnesses, the IgM blot in early disease had a sensitivity of 32% and a specificity of 100% the IgG blot after the first weeks of infection had a sensitivity of 83% and a specificity of 95%. In a retrospective analysis of 225 case and control subjects, the best discriminatory ability of test criteria was obtained by requiring at least 2 of the 8 most common IgM bands in early disease (18, 21, 28, 37, 41, 45, 58, and 93 kDa) and by requiring at least 5 of the 10 most frequent IgG bands after the first weeks of infection (18, 21, 28, 30, 39, 41, 45, 58, 66, and 93 kDa). Thus, Western blotting can be used to increase the specificity of serologic testing in Lyme disease.
There are currently no accepted criteria for positive Western blots in Lyme disease. Among patients with indeterminate IgG responses by ELISA, 6 of 9 patients with active Lyme disease had positive blots compared with 2 of 34 patients with other illnesses (P <.
