A new modified gamma-%CDT method improves the detection of problem drinking: studies in alcoholics with or without liver disease.

BACKGROUND: The detection of excessive alcohol consumption by laboratory methods continues to lack sensitivity and specificity. Recent studies have suggested that diagnostic improvement may be achieved by combining carbohydrate-deficient transferrin (CDT) and gamma-glutamyltransferase (GT) measurements into a marker defined as gamma-CDT.
METHODS: We developed a new approach for determining gamma-CDT by using the data obtained from the Axis %CDT turbidimetric assays. Marker results were compared in the assessment of 65 alcoholics, who were either with (n=34) or without (n=31) liver disease, as analysed by clinical, laboratory, and morphological criteria. Reference individuals were 45 healthy volunteers who were either social drinkers or abstainers.
RESULTS: Gamma-GT and CDT results derived from both CDTect and %CDT measurements were used to calculate marker ratios as follows 0.8 x ln(GT)+1.3 x ln(CDT). With the established cut-off of 4.0 for the gamma-%CDT, the sensitivity of this method was 94% for men and 82% for women, as compared to 61% and 46% for %CDT and 70% and 73% for GT. The gamma-%CDT method was less dependent on liver status than the various other markers and showed the highest correlation with self-reported alcohol consumption (r=0.7254).
CONCLUSIONS: The data indicates that the new gamma-%CDT method yields improved diagnostic accuracy for the detection of excessive ethanol consumption.