Anti-HCV reactive blood donors: clinical and epidemiological factors associated with false-reactive results.

BACKGROUND: In certain clinical settings, false-reactive anti-hepatitis C virus (HCV) results are rare because the majority of persons being tested have evidence of liver disease and the specificity of the screening assays is high. However, among healthy populations, such as blood donors, mainly in regions with a low prevalence of HCV infection, this situation does occur. In this study, we sought to assess clinical, epidemiological, and laboratory characteristics of blood donors with false-reactive anti-HCV screening tests. METHODS: This retrospective cross-sectional study included 537 anti-HCV reactive blood donors referred to a tertiary care centre for liver diseases. RESULTS: The mean age was 36.5+/-11.2 years and 71.8% were men. Blood donors of older age (P=0.010), history of alcohol abuse (P=0.039), past transfusion (P<0.001), intravenous drug use (P<0.001), and with antibody against core antigen of hepatitis B virus reactivity (P=0.003) were less likely to have a false-reactive anti-HCV result. By multivariate analysis, only the absence of parenteral risk factors (prior transfusion and intravenous drug use) was independently associated with false-reactive anti-HCV tests. CONCLUSION: Blood donors with reactive anti-HCV screening tests with no risk factors for parenterally acquired HCV infection are more likely to present with false-reactive results.

High prevalence of celiac disease in Brazilian blood donor volunteers based on screening by IgA antitissue transglutaminase antibody.

OBJECTIVE: To study the prevalence of celiac disease among blood donor volunteers based on screening by IgA antitissue transglutaminase antibody, followed by a confirmatory small intestine biopsy. METHODS: The transversal study involved 3000 potential blood donors, residing in the city of Sao Paulo, Brazil. The participants were gender divided into 1500 men and 1500 women, with an average age 34.4+/-10.8 years, and included blood donor volunteers who could be turned down owing to anemia. All participants answered a questionnaire concerning the presence of diarrhea, constipation or abdominal pain during the 3 months before the study. Each participant with human recombinant IgA antitissue transglutaminase antibody level above 10 U/ml was invited to undergo a small intestine biopsy by means of an upper gastrointestinal endoscopy. The presence of villous atrophy and a positive antibody test were suggestive of possible celiac disease. RESULTS: Antitissue transglutaminase antibody was positive in 1.5% (45/3000) of the study population. Among the antibody-positive group, 21 (46.6%) agreed to have a biopsy performed, and within them the histological pattern of villous atrophy was confirmed in 66.7% (14/21). Consequently, the suggestive prevalence of celiac disease was at the minimum, one per 214 of the potential blood donor volunteers. A significant association was found between celiac disease and the symptoms of diarrhea, constipation and abdominal pain. CONCLUSIONS: The prevalence of celiac disease in Sao Paulo city is high and comparable to that observed in European countries. It is possible that in Brazil the prevalence of this disease had previously been underestimated.