Prevalence of Viral Hepatitis Markers and Effectiveness of ALT as a Surrogate Marker in Volunteer Donors

Cho, Nam Sun; Ahn, Hyeong Sik

Abstract

BACKGROUND: The major serious risk of blood transfusion is post-transfusion hepatitis. Currently HBsAg, anti-HCV and serum alanine aminotransferase (ALT) assays are screened for potential blood donors to prevent transfusion associated hepatitis in Korea. But the effectiveness of serum ALT as a surrogate marker for the screening of non-A, non-B hepatitis is controversial. The present study was designed to evaluate the prevalence of hepatitis markers in Korean blood donors and the usefulness of ALT as a surrogate marker.
METHODS
The prevalence rates of anti-HCV and HBsAg were analyzed by age, sex and ALT cut-off level in 405,931 blood donors. The current anti-HCV EIA (LG HCD 3.0 ) comparing to anti-HCV confirmatory immunoblot assay (LG HCD confirm ) and ALT test were evaluated.
RESULTS
The positive rate of HBsAg was 3.32% and higher in male across all age group (p<0.01). The rate increased as age increases up to thirties and decreased thereafter. The positive rate of anti-HCV was 0.24% in EIA, and higher in female across all age group except for teenage group (p<0.01). The rate increased as age increases up to fifties (p<0.01). Results of immunoblot assay showed 64% disaccordance with that of EIA and the rate of disaccord was high in female and young age group. The rate of mixed infection of hepatitis B and C was 0.003%. ALT level was within normal range in 95.2% of donors, and the prevalences of HBsAg and anti-HCV were higher as ALT increased above normal level (p<0.01). The sensitivity of ALT in identifying hepatitis C was 34.5% at 45 IU/L, and 22.8% at 65 IU/L. The most accurate cut-off level of ALT for hepatitis C was 23 IU/L in Receiver-Operating Characteristic (ROC) plot and the sensitivity and specificity were 65.5% and 79.9% at that level.
CONCLUSION
In contrast to HBsAg, the prevalence rate of anti-HCV showed different pattern in that it was higher in female and continuously increased up to fifties. Confirmatory assay for hepatitis C should be done for the high false positivity of current anti-HCV EIA. The sensitivity and positive predictive value of ALT was so poor that ALT was not found to be useful as a surrogate marker for hepatitis C, but the discontinuance of ALT testing of blood donors needs to be evaluated by further studies.