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Reliability of the third‐generation recombinant immunoblot assay for hepatitis C virus
Author(s) -
Damen M.,
Zaaijer H.L.,
Cuypers H.T.,
Vrielink H.,
Poel C.L.,
Reesink H.W.,
Lelie P.N.
Publication year - 1995
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1046/j.1537-2995.1995.35996029158.x
Subject(s) - hepatitis c virus , viremia , virology , recombinant dna , antigen , medicine , immunology , flaviviridae , virus , hepatitis c , biology , gene , biochemistry
BACKGROUND : In a confirmatory laboratory, the second‐generation recombinant immunoblot assay (RIBA‐2) was replaced by the third‐ generation RIBA (RIBA‐3) in March 1993. The aim of this validation study was to compare the sensitivity and specificity of RIBA‐2 and RIBA‐ 3 in a routine setting, by using a validated hepatitis C virus (HCV) RNA polymerase chain reaction to establish plasma viremia. STUDY DESIGN AND METHODS : RIBA‐2 testing was performed (March 1991‐March 1993) in 593 HCV RNA‐positive and 1498 HCV RNA‐negative subjects. RIBA‐3 testing was performed (March 1993‐May 1994) in 220 HCV RNA‐positive and 530 HCV RNA‐negative subjects. All samples reacted for anti‐HCV in enzyme‐ linked immunosorbent assay. RESULTS : In HCV RNA‐positive individuals, the sensitivity of RIBA‐3 was significantly higher than that of RIBA‐2 (99.5% vs. 93.3%, p = 0.0005). This was not caused by inclusion of the NS5 antigen, but by a higher sensitivity of the antigens c33 and c100 (RIBA‐2: 94.3% and 62.6%; RIBA‐3: 99.5% and 88.6%). Replacement of the c22 and c100 recombinant proteins by synthetic peptides significantly reduced nonspecific reactivity against these antigens (p < 0.0001). Unfortunately, increased nonspecific reactivity against the modified c33 antigen and the new NS5 antigen canceled out this effect. Two‐band reactivity occurred more often in nonviremic persons than in viremic persons (32.7% vs. 8.2%, p < 0.0001). Risk factors for HCV infection were less frequently observed in 11 blood donors with two‐band reactivity than in 6 blood donors with other positive RIBA‐3 patterns (18% vs. 83%, p = 0.03). CONCLUSION : The higher sensitivity of RIBA‐3 significantly reduced the number of indeterminate test results in HCV RNA‐positive persons. Confirmatory laboratories must be aware of the frequent occurrence of nonspecific, isolated reactivity and even nonspecific, two‐band reactivity in anti‐HCV enzyme‐linked immunosorbent assay‐reactive blood donors.