LIMITED UTILITY OF ALANINE AMINOTRANSFERASE SCREENING OF HEPATITIS-C ANTIBODY-SCREENED BLOOD-DONORS

BACKGROUND: The introduction of hepatitis C virus (HCV) screening has significantly reduced the frequency of posttransfusion hepatitis C. To examine the current added value of alanine aminotransferase (ALT) scr eening, all donor screening at two large blood centers was reviewed. S TUDY DESIGN AND METHODS: From July 1991 through March 1994, 1,258,000 allogeneic blood donors were screened by enzyme immunoassay for anti-H CV: 343,000 donations by the first-generation test (HCV 1.0) and 915,0 00 donations by the second-generation test (HCV 2.0). Donations with p ositive EIA results were confirmed with a recombinant immunoblot assay . RESULTS: Of these donors, 1,637 (0.13%) were confirmed as HCV-positi ve and 21,666 (1.72%) had elevated ALT. To estimate the additional mar gin of safety due to ALT screening, all donors who seroconverted were reviewed, and those donors who had elevated ALT but were HCV negative on a previous donation were identified. One hundred eleven HCV serocon versions were observed: 19 seroconversions from HCV 1.0-negative to HC V 1.0-confirmed-positive, 82 apparent seroconversions from HCV 1.0-neg ative to HCV 2.0-confirmed-positive, and 10 seroconversions from HCV 2 .0-negative to HCV 2.0-confirmed-positive. The number of apparent HCV 1.0-negative to HCV 2.0-positive seroconversions was much greater than expected, which reflected the in creased sensitivity of HCV 2.0. Only 15 donors were identified who had an elevated ALT on a previous HCV-n egative blood donation, and all of these were among those who apparent ly seroconverted from HCV 1.0-negative to HCV 2.0-confirmed-positive. Out of the 10 HCV 2.0-seroconverting donors, no donor was found who wa s initially HCV 2.0 negative with elevated ALT and later was HCV 2.0 p ositive; nor were such donors found among 4 additional HCV 2.0-serocon verting donors. CONCLUSION: With the introduction of HCV 2.0 screening , ALT appears to have little value as a surrogate test for hepatitis C , and ALT testing was unable to detect any donors who later seroconver ted, as detected by HCV 2.0.