title: Detection of antibodies against hepatitis A virus in eluates of blood spotted on filter-paper: a pilot study in Rio de Janeiro, Brazil.
abstract: The validity of blood spotted on to filter-paper (BSOFP) eluates for the detection of antibodies against hepatitis A virus (HAV) was investigated in 718 individuals (children and adults) during a field study in a small area in Rio de Janeiro State, Brazil. Serum samples were considered the 'gold standard'. BSOFP eluates were analyzed by 2 different techniques: microplate competitive enzyme-linked immunosorbent assay (ELISA) of the whole study group and microparticle enzyme immune assay (MEIA) of a subsample of 59 individuals. For BSOFP eluates by ELISA, sensitivity and specificity were 89.6% (95% CI: 84.7-93.1) and 97.5% (95% CI: 95.6-98.7), respectively. For a seroprevalence of anti-HAV antibodies of 32%, the positive predictive value was 94.5% (95% CI: 90.3-97.0) and the negative predictive value was 95.2% (95% CI: 92.8-96.8). The test efficiency was 95.0% (95% CI: 93.1-96.4). Similar results were found for BSOFP eluates by MEIA. Agreement between the 2 techniques used for BSOFP (ELISA and MEIA) was also high (kappa = 0.93). These results encourage the more widespread application of BSOFP as a means of surveillance for large-scale epidemiological studies for hepatitis A.
authors.affiliation: Núcleo de Estudos de Saúde Coletiva da Universidade Federal do Rio de Janeiro (NESC/UFRJ), Brazil. liz@acd.ufrj.br
authors.forename: L M
authors.initials: LM
authors.lastname: de Almeida
authors.forename: R S
authors.initials: RS
authors.lastname: Azevedo
authors.forename: A A
authors.initials: AA
authors.lastname: Guimarães
authors.forename: E da S
authors.initials: Eda S
authors.lastname: Coutinho
authors.forename: C J
authors.initials: CJ
authors.lastname: Struchiner
authors.forename: E
authors.initials: E
authors.lastname: Massad
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D015415:Biomarkers / Q000097:blood; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D006506:Hepatitis A / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D035922:Hepatitis A Antibodies; D006508:Hepatitis Antibodies / Q000097:blood*; D006801:Humans; D007223:Infant; D010865:Pilot Projects; D011237:Predictive Value of Tests; D015995:Prevalence; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D035922:Hepatitis A Antibodies; D006508:Hepatitis Antibodies