title: Polymerase chain reaction in comparison with serological tests for early diagnosis of human leptospirosis.
abstract: The aim of this study was to compare the sensitivity and specificity of polymerase chain reaction (PCR) using two primer pairs and combined with blood culture, immunoglobulin M enzyme-linked immunosorbent assay (IgM ELISA), microscopic agglutination test (MAT) and slide agglutination test (SAT) in the diagnosis of human leptospirosis. We analysed 124 serum samples: 60 from patients with confirmed leptospirosis, 20 from patients with other diseases and 44 from healthy individuals. Analysing the first serum sample collected during the first 3-8 days of disease, the sensitivities of the four tests MAT, IgM ELISA, SAT and PCR were, respectively, 69.0%, 79.3%, 72.4% and 62%. In subsequent samples, those same sensitivities were, respectively, 95.4%, 100%, 100% and 72.7% in samples collected from days 9 to 14 and 88.9%, 88.9%, 77.8% and 44.4% in those collected from days 15 to 42. The most specific method (at 100%) was PCR and the least specific (at 89.1%) was IgM ELISA. Although we found PCR to be less sensitive than the serological tests over the course of the disease, our data indicate that PCR was the most sensitive in those initial serum samples presenting no specific antibodies detectable by any of the serological methods tested. We also recommend that PCR can be used in combination with serological tests as we found that this improves the sensitivity of the diagnosis of leptospirosis in the first phase of the disease (93.1-96.5%).
authors.affiliation: Laboratory of Medical Investigation in Immunology, Hospital das Clínicas, University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Claudia
authors.initials: C
authors.lastname: de Abreu Fonseca
authors.forename: Vera Lúcia
authors.initials: VL
authors.lastname: Teixeira de Freitas
authors.forename: Eliete
authors.initials: E
authors.lastname: Caló Romero
authors.forename: Claudia
authors.initials: C
authors.lastname: Spinosa
authors.forename: Maria Carmem
authors.initials: MC
authors.lastname: Arroyo Sanches
authors.forename: Marcos Vinícius
authors.initials: MV
authors.lastname: da Silva
authors.forename: Maria Aparecida
authors.initials: MA
authors.lastname: Shikanai-Yasuda
mesh_terms: D000328:Adult; D000372:Agglutination Tests / Q000379:methods*; D000907:Antibodies, Bacterial / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D007922:Leptospirosis / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M