title: High proportion of false positive reactions among donors with anti-HCV antibodies in a low prevalence area.
abstract: Among 39,656 voluntary blood donors in Okinawa Prefecture, Japan, 115 (0.29%) were repeatedly reactive for antibody to hepatitis C virus (anti-HCV) by second generation (2nd-gen) passive hemagglutination assay (PHA). Positive serum samples were tested for anti-HCV using three different enzyme immunosorbent assays (ELISAs; Abbott 2nd EIA, UBI-HCV-EIA, JCC-2) and for HCV-RNA by the polymerase chain reaction (PCR). The 115 2nd-gen PHA-positive sera were divided into three groups according to the agglutination titers; > 2(10) (high titer group), 2(7)-2(9) (median), 2(5)-2(6) (low). All but one serum (44/45) in the high PHA titer group reacted in each of the three second screening ELISAs. Furthermore, 43 (97.7%) of the 44 sera contained HCV-RNA by PCR. In the median titer group, 11 of the 13 samples tested were positive by each of the three ELISAs, and 4 (36.4%) of the 11 showed reaction by PCR. On the other hand, all of the 38 sera tested in the low titer group were negative for HCV-RNA by PCR, and 24 of the 38 were also negative by each of the three ELISAs. Most of the low titer positive reactions in the 2nd-gen agglutination assay seemed to be false positive. In Okinawa Prefecture, the prevalence of anti-HCV among blood donors is much lower than in the rest of Japan (0.29% vs. 1.11%). Moreover, a significant proportion of these sera were low titer by the PHA assay.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, School of Medicine, Okinawa, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sakugawa
authors.forename: H
authors.initials: H
authors.lastname: Nakasone
authors.forename: T
authors.initials: T
authors.lastname: Nakayoshi
authors.forename: F
authors.initials: F
authors.lastname: Kinjo
authors.forename: A
authors.initials: A
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Yakabi
authors.forename: H
authors.initials: H
authors.lastname: Zukeran
authors.forename: Y
authors.initials: Y
authors.lastname: Miyagi
authors.forename: R
authors.initials: R
authors.lastname: Taira
authors.forename: K
authors.initials: K
authors.lastname: Koja
mesh_terms: D001782:Blood Donors; D005189:False Positive Reactions; D006386:Hemagglutination Tests; D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000453:epidemiology* / Q000276:immunology; D018937:Hepatitis C Antibodies / Q000097:blood*; D006801:Humans; D007163:Immunosorbent Techniques; D007564:Japan / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012367:RNA, Viral / Q000032:analysis
chemical_list: D018937:Hepatitis C Antibodies; D012367:RNA, Viral