Serum carbohydrate-deficient transferrin (CDT) is currently widely used as a biochemical marker of alcohol misuse. However, various recent studies have questioned the diagnostic value of this parameter and reported low levels of both specificity and sensitivity, especially in women. Thus, we sought to identify sub-groups of female individuals in which CDT is elevated independently of alcohol consumption. Significantly increased CDT levels were found in catabolic disease states due to psychiatric disorders distinct from alcoholism. None of those patients reported frequent alcohol consumption. CDT therefore appears also to be increased by metabolic processes distinct from alcohol degradation. Possible biochemical mechanisms of this phenomenon are discussed. As a consequence of these findings, the measurement of CDT alone is not suitable to screen for alcohol misuse in catabolic subjects.