Validation study of Axis-Shield carbohydrate-deficient transferrin (CDT) on ARCHITECT® chemistry analyzer

Background: Carbohydrate-deficient transferrin (CDT) is a biochemical marker used for identifying chronic alcohol intake. We developed and validated an ARCHITECT c8000 (R) (Abbott) instrument application for the Axis-Shield %CDT immunoassay. Methods: Standard CLSI (Clinical and Laboratory Standards Institute) evaluation protocols were performed. Results: The Axis-Shield %CDT ARCHITECT (R) method was standardized against the Axis-Shield %CDT microtiter test by linear regression analysis (n=50 mean of duplicate, R=0.996). Method comparison by Deming regression revealed a slope of 1.01 and an intercept of -0.03 with Axis-Shield %CDT microtiter test (n=50 in duplicate, R=0.995), and a slope of 0.82 and an intercept of 1.09 with HPLC method (n=47 in duplicate, R=0.990) as the candidate IFCC (International Federation of Clinical Chemistry and Laboratory Medicine) reference method. The predicted medical decision points (MDPs) are both 2.6% and equal the MDP that is generally used for the Axis-Shield %CDT tests. Precision derived from pooled patient sera (low level) and commercially available control material (high level) was excellent. Total variation was 3.2% and 1.8%, respectively. Conclusions: The Axis-Shield %CDT ARCHITECT (R) method, as one of the first Axis-Shield applications on a large-scale analyzer, is a reliable test for routine %CDT analysis providing precise and well-standardized %CDT results.