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Results for “False Positive Reactions”

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At least 73 records · Page 4Linked to original sources
PubMed1995

High proportion of false positive reactions among donors with anti-HCV antibodies in a low prevalence area.

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)

Blood Donors↗
PubMed1979

The occurrence and treatment of false positive reactions in enzyme-linked immunosorbent assays (ELISA) for the presence of fungal antigens in clinical samples.

Non-specific positive reactions have been revealed in enzyme-linked immunosorbent assays (ELISA) of sera for the presence of fungal antigen. These false positives were recognized by their occurrence in tests for both Candida albicans and Aspergillus fumigatus antigens and by their response to dithiothreitol, combined with their reaction with non-immune rabbit globulin. A scheme is proposed which differentiates between true and false positive reactions. Use of fractionated anti-fungal globulin in conjugates reduced the incidence of false positive results in sera from hospitalized patients and eliminated them from sera of healthy subjects. The test scheme was applied to two panels of sera containing samples from patients with (a) invasive candidosis and (b) invasive aspergillosis. The relevance of ELISA tests for the detection of fungal antigen in human serum is discussed.

Animals↗