Carbohydrate-deficient transferrin in the assessment of harmful alcohol consumption: diagnostic performance and clinical significance

The last decade saw the emergence of carbohydrate-deficient transferrin (CD T) as the most promising marker for the diagnosis of alcohol abuse. Daily a lcohol consumption of four beers, four glasses of wine or three standard dr inks causes increased concentrations of CDT in serum. CDT is serum pz trans ferrin with a reduced content of oligosaccharides due to the detrimental ef fects of alcohol metabolism of? the glycosylation pathway, of hepatocytes a nd/or the increased activity, of circulating glycosidases in serum. Most cu rrent CDT procedure es entail separation of normal transferrin from CDT in a charged matrix-like isoelectricfocusing and ion exchange chromatography, followed by detection/quantitation of CDT by a myriad of immunoassays: immu noblotting, radioimmunoassay, enzyme immunoassay and nephelometry. New CDT procedures present the advantages of improved performance, inexpensive auto mation and CDT results Expressed as a percentage of total serum transferrin . CDT's major asset is its high specificity in well-defined populations i.e . individuals ingesting 60g alcohol daily,for at least a week. The sensitiv ity rates, which vary between 22% and 81%, depend on the amount of alcohol ingested, time of sample collection after the cessation of drinking, age, g ender and the cut-off point chosen for analysis of tests' results. Regardin g clinical applications, best outcome is achieved when the test is used to confirm a suspicion of alcohol abuse and when monitoring abstinence and rel apses. The low prevalence of alcohol abuse in the general population challe nges its use as a screening test. With the advent of inexpensive automation and the constant emergence of innovative, improved tests, we are seeing th e rise of a new era in alcohol abuse diagnosis as affordability and educati on allows widespread use of CDT in a variety of settings.