Biomarkers Insensitive for Detecting Heavy Alcohol Use

Carbohydrate-deficient transferrin (CDT), gamma-glutamyltransferase (GGT), and breath alcohol are candidate biomarkers to detect heavy drinking. Researchers assessed the operating characteristics of CDT, GGT, and breath alcohol measured to detect heavy drinking* at 6-month follow-up among 402 patients with alcohol dependence and heavy drinking. The self-reported timeline follow-back validated calendar measure for alcohol use was the reference standard.

• CDT yielded the best performance with area under the receiver-operating curve (AUC) that suggested fair to good accuracy: % CDT had higher sensitivity with better likelihood positive and negative than GGT or breath alcohol, but missed 34–59% of the cases, depending on which cutoff was chosen and which outcome was used.
• The optimal % CDT cut-point for any heavy drinking was 1.5% (sensitivity 51%, specificity 90%).
• For recurrent heavy drinking** it was 1.3% (sensitivity 76%, specificity 70%).
• For persistent heavy drinking*** it was 1.4% (sensitivity 81%, specificity 70%).
• For GGT, the estimated AUC suggested poor test accuracy.
• The optimal GGT cut-point for any heavy drinking was 24 IU/l (sensitivity 72%, specificity 49%).
• For recurrent heavy drinking, it was 27 IU/l (sensitivity 76%, specificity 54%).
• For persistent heavy drinking, it was 40 IU/l (sensitivity 55%, specificity 70%).
• For breath alcohol where >0 indicated a positive test, sensitivity ranged 20–31% and specificity ranged 91–94%.

Comments:

These biomarkers do not have sufficient diagnostic accuracy (sensitivity in particular) to be used without self-report measures in patients with alcohol dependence.While self-reported, the reference standard for this study was highly detailed and included confidentiality protections not usually available in clinical practice. A thorough history is likely to provide more useful information about alcohol use than laboratory tests in both research and clinical settings.

Alexander Y. Walley, MD, MSc

Reference:

Bertholet N, Winter MR, Cheng DM, et al. How accurate are blood (or breath) tests for identifying self-reported heavy drinking among people with alcohol dependence? Alcohol Alcohol. 2014;49:423–429.