Carbohydrate-deficient transferrin (CDT) is used as a biomarker of sustained high alcohol consumption. The currently available measurement procedures for CDT are based on various analytical techniques (HPLC, capillary electrophoresis, nephelometry), some differing in the definition of the analyte and using different reference intervals and cut-off values. The Working Group on Standardization of CDT (WG-CDT), initiated by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), has validated an HPLC candidate reference measurement procedure (cRMP) for CDT (% disialotransferrin to total transferrin based on peak areas), demonstrating that it is suitable as a reference measurement procedure (RMP) for CDT. Presented is a detailed description of the cRMP and its calibration. Practical aspects on how to treat genetic variant and so-called di-tri bridge samples are described. Results of method performance characteristics, as demanded by ISO 15189 and ISO 15193, are given, as well as the reference interval and measurement uncertainty and how to deal with that in routine use. The correlation of the cRMP with commercial CDT procedures and the performance of the cRMP in a network of laboratories are also presented. The performance of the CDT cRMP in combination with previously developed commutable calibrators allows for standardization of the currently available commercial measurement procedures for CDT. The cRMP has recently been approved by the IFCC and will be from now on be known as the IFCC-RMP for CDT, while CDT results standardized according to this RMP should be indicated as CDTIFCC.
Keywords: Alcohol biomarker; CDT; Disialotransferrin; HPLC; Reference Measurement Procedure (RMP); Standardization.
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