Gamma-glutamyltranspeptidase and carbohydrate deficient transferrin: alternative measures of excessive alcohol consumption.

Both gamma-glutamyltranspeptidase and carbohydrate-deficient transferrin have been extensively researched as biological markers of heavy alcohol consumption. The current study briefly describes each test, identifies subject variables that influence their relative sensitivities and specificities, and examines issues surrounding use of the two markers in combination. In addition, this study suggests five design features that should characterize projects evaluating the validity of biochemical markers.