Standardisation and use of the alcohol biomarker carbohydrate-deficient transferrin (CDT)

Carbohydrate-deficient transferrin (CDT) is a glycoform profile of serum transferrin that increases in response to sustained high alcohol intake and over the last decades has become an important alcohol biomarker with clinical and forensic applications. However, the wide range of CDT measurement procedures has resulted in lack of uniform results and reference limits, and hampered comparison of results. In 2005, the IFCC therefore founded a special working group (WG) aiming for standardisation of CDT measurement. This review summarises the history of CDT and the actions taken by the WG-CDT. Initial steps included the definition of the measurand (serum disialotransferrin to total transferrin fraction expressed in %), and the determination of a well-defined anion-exchange HPLC procedure as the candidate reference measurement procedure (cRMP). Subsequent achievements were the establishment of a network of reference laboratories to perform the cRMP, setting a reference interval, and development of a reference material based on human serum for which the laboratory network assign values. Using a set of reference materials for calibration allowed for achieving equivalence of results of all present CDT measurement procedures. The final steps of the WG-CDT have been a full validation of the cRMP to make it an IFCC approved RMP, and providing guidance for international standardisation of all CDT measurement procedures. •The IFCC WG-CDT aims to establish international standardisation of CDT.•Serum disialotransferrin to total transferrin fraction (%) was defined as the measurand for CDT.•A well-defined HPLC method was selected as the candidate reference method for CDT.•A reference laboratory network assigns target values for secondary CDT serum calibrators.•CDT standardisation allowed direct comparison of values by different routine methods.