Should we use carbohydrate-deficient transferrin instead of beta-glutamyltransferase for detecting problem drinkers? A systematic review and metaanalysis

Background: Carbohydrate-deficient transferrin (CDT) has been used as a tes t for excessive alcohol consumption in research, clinical, and medico-legal settings, but there remain conflicting data on its accuracy, with sensitiv ities ranging from <20% to 100%. We examined evidence of its benefit over a conventional and less expensive test, <gamma>-glutamyltransferase (GGT), a nd compared the accuracy of different CDT assay methods. Methods: We performed a systematic review using summary ROC analysis of 110 studies prior to June 1998 on the use of CDT in the detection of alcohol d ependence or hazardous/harmful alcohol use. Results: We identified several potential sources of bias in studies. In stu dies examining CDT and GGT in the same subjects, subject characteristics we re less likely to influence the comparison. In such paired studies, the ori ginal Pharmacia CDT assay was significantly more accurate than GGT, but the modified CDTect assay did not perform as well as the original and was not significantly better than GGT. The accuracy of the AXIS %CDT assay was stat istically indistinguishable from modified CDTect. Several CDT assay methods appeared promising, in particular, liquid chromatography (chromatofocusing , HPLC, fast protein liquid chromatography) and isoelectric focusing, but t here were insufficient paired studies from which to draw firm conclusions. Conclusions: In studies published before June 1998, the results obtained wi th commercially available CDT assays were not significantly better than GGT as markers of excessive alcohol use in paired studies. Further high-qualit y studies comparing CDTect (modified) and other CDT assays with GGT in the same subjects are needed. (C) 2000 American Association for Clinical Chemis try.