Non-specific and specific anti-HCV results correlated to age, sex, transaminase, rhesus blood group and follow-up in blood donors.
Second generation enzyme immunoassays (EIA-2) for antibodies to hepatitis C virus (anti-HCV) have a higher specificity and sensitivity than first generation enzyme immunoassays (EIA-1). We studied how many anti-HCV-positive blood donors were missed by the EIA-1, how many were false positive, how false-positive donors should be dealt with and how the results of the EIA-2 correlate to demographic data and serum alanine aminotransferase (ALT) level. A total of 208, 544 northern German blood donors, not preselected for anti-HCV negativity, were tested for anti-HCV with EIA-2 and, if repeatability reactive (rr), were retested with a licensed supplementary test (RIBA-2). 0.43% of the donors were EIA-2 rr, but only 0.12% of women and 0.09% of men were RIBA-2 positive. RIBA-2 positivity rates were very low in donors 18 to 27 years old (0.03% and 0.05%) and rose with age in women but not in men. Infected women were significantly more often Rhesus-negative than men. The rate of unspecifically positive EIA-2 results (entirely negative in RIBA-2) increased with age in both sexes and did not correlate with ALT. The ALT distribution was age-dependent with a different pattern for men and women. Confirmation of EIA-2 results with RIBA was rare when ALT was low and frequent when ALT was high. ALT screening before introduction of Anti-HCV detected one out of six infected donors. To exclude this one infectious donation, 46 uninfected donations had to be excluded in addition. Only 8% of the then RIBA-2-positive donors were not detected by EIA-1. Apparent seroconversions in EIA-2 are usually not specific; only 1 out of 66 apparent seroconversions could be confirmed by RIBA-2 suggesting recent HCV infection. 0.15% of the donor population showed an inconsistent EIA-2 pattern during follow-up. We conclude that donors should not be excluded from further donations, even on the basis of multiple EIA-1 positive results or on the basis of only one EIA-2 positive donation. Anti-D-immunoglobulin prophylaxis may have been a source of infection in some Rhesus-negative women. ALT screening should not be discontinued because recent HCV infection can be detected earlier by ALT than by anti-HCV, but exclusion limits should be elevated to increase specificity and limit unnecessary exclusion of donations.
Caspari
G
G
Institute of Medical Virology, Justus-Liebig-University, Giessen, Federal Republic of Germany.
Gerlich
W H
WH
Beyer
J
J
Schmitt
H
H
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000410:Alanine Transaminase / Q000097:blood*; D000465:Algorithms; D001782:Blood Donors; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D016174:Hepacivirus / Q000276:immunology / Q000302:isolation & purification*; D018937:Hepatitis C Antibodies / Q000097:blood* / Q000276:immunology; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011933:Reagent Kits, Diagnostic; D012204:Rh-Hr Blood-Group System; D012680:Sensitivity and Specificity; D012737:Sex Factors
D018937:Hepatitis C Antibodies; D011933:Reagent Kits, Diagnostic; D012204:Rh-Hr Blood-Group System; D000410:Alanine Transaminase