Carbohydrate-deficient transferrin: utility of HPLC in handling atypical samples uninterpretable by capillary electrophoresis.

Aims: Carbohydrate-deficient transferrin (CDT) is a marker of chronic alcohol abuse. Uninterpretable (atypical) CDT patterns have been detected by both capillary electrophoresis (CE) and HPLC. The aim of this study was to evaluate the performance of HPLC as a second-line test for the interpretation of most frequent atypical CDT profiles detected by CE. Methods: CDT was analyzed by CE (Capillarys 2, Sebia) on 9120 consecutive samples in a routine laboratory setting during a 2-year period. A commercial method (ClinRep CDT kit, Recipe) was employed to retest 123 (1.4%) samples with atypical CDT patterns on a Prominence LC-20AT HPLC (Shimadzu). Results: CE-uninterpretable samples were categorized as having low transferrin (Tf) concentration (LT; n = 42, 0.5%), di-trisialotransferrin bridging (D-TB; n = 63, 0.7%) or atypical peak profile (APP; n = 18, 0.2%). CDT was detectable by HPLC in 58 of 123 (47%) samples including 21 of 42 (50%) with LT, 27 of 63 (43%) with D-TB and 10 of 18 (56%) with APP. Conclusions: Second-line HPLC testing reduced uninterpretable samples by 47%, with similar rates of improvement regardless of the type of CDT pattern. The usefulness of HPLC as a second-line test for CDT should be evaluated according to cost-benefit considerations in the context of each laboratory.