RESUMO
Leptospirosis is a common and underdiagnosed zoonosis. Two rapid assays for serological diagnosis of acute leptospirosis in diagnostic laboratories, the immunoglobulin M (IgM)-dipstick assay and the indirect hemagglutination assay (IHA), were evaluated and compared with standard assays. Sera were examined from 104 patients admitted to a hospital for investigation in a leptospirosis diagnostic protocol. Specimens for serology were taken on days 1 and 4 of the patients' hospital stay. Antibodies were detected using an IgM-enzyme-linked immunosorbent assay (ELISA), microscopic agglutination test (MAT), an IgM-dipstick assay, and an IHA. Fifty-one patients were found to have leptospirosis. The sensitivity of the IgM-dipstick assay was 98%, its specificity was 90.6%, its positive predictive value was 90.9%, and its negative predictive value was 98%. The sensitivity of the IHA was 92.2%, its specificity was 94.4%, its positive predictive value was 95.9%, and its negative predictive value was 92.7%. The standard IgM-ELISA and MAT, were positive in the first samples tested from 67 and 55% of the cases, respectively, and the rapid IgM-dipstick assay and IHA were positive in 71 and 49%, respectively, in the first sample tested. Both rapid assays are highly sensitive and specific. Neither requires specialized equipment, and both are suitable for use in diagnostic laboratories.
Assuntos
Testes de Hemaglutinação/normas , Leptospirose/diagnóstico , Fitas Reagentes/normas , Doença Aguda , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina M/análise , Leptospirose/imunologia , Valor Preditivo dos Testes , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: To evaluate two rapid assays for serological diagnosis of acute leptospirosis in diagnostic laboratories. DESIGN AND METHODS: 209 specimens were examined from 104 patients admitted to hospital for investigation in a leptospirosis diagnostic protocol. Specimens for serology were taken on days 1 and 4 of the hospital admission. Antibodies were detected using IgM-ELISA, microscopic agglutination (MAT), an IgM-dipstick assay and indirect haemagglutination assay. RESULTS: 51 patients were found to have leptospirosis. The sensitivity of the IgM-dipstick was 98 percent, specificity was 90.6 percent, positive predictive value was 90.9 percent and the negative predictive value was 98 percent. The sensitivity of IHA was 92. percent, specificity was 94.4 percent, positive predictive value was 95.9 percent and negative predictive value was 92.7 percent. The IgM-dipstick assay was positive in 71 percent of the cases in the first sample tested. CONCLUSIONS: Both assays are highly sensitive and specific. Neither requires specialized equipment, and both are suitable for use in diagnostic laboratories.(Au)