Significance of alanine aminotransferase testing in blood donor screening in Chongqing, China: a 7-year retrospective analysis

Since 1993, alanine aminotransferase (ALT) testing has been mandatory for blood donor screening in China. This study aimed to evaluate the significance of ALT testing for transfusion safety. Between January 2012 and December 2018, 122236 blood donor samples were routinely screened by the enzyme-linked immunosorbent assay method for transfusion-transmitted disease markers (TTDM) and by the kinetics method for ALT. Out of 2705 (2.21%) seropositive donors, 291 (10.76%) tested positive for ALT alone and were categorized as ALT-only positive donors. Fourteen ALT-only positive donors who all tested negative in subsequent TTDM and nucleic acid testing (NAT) screening were followed up. The return rate for ALT-only positive donors was reduced by 4.1 times as compared with qualified blood donors (P<0.000). The results suggest that ALT testing does not make a significant contribution to reducing the risk of transfusion-transmitted diseases. Furthermore, being disqualified even once owing to elevated ALT levels has a significant impact on donors' return behavior. Therefore, a suitable cutoff value for ALT testing should be considered based on the evaluated risk in both blood safety and supply.