From the Guidelines
Carbohydrate-deficient transferrin (CDT) is the most reliable serum marker for detecting chronic alcohol abuse, with a sensitivity of 25%-84% and specificity of 70%-98% 1.
Serum Markers for Alcohol Consumption
The most commonly used serum markers for detecting alcohol consumption include:
- Gamma-glutamyl transferase (GGT), which rises after 1-2 weeks of heavy drinking and remains elevated for 2-6 weeks after abstinence, with a sensitivity of 42-86% and specificity of 40-84% 1
- Mean corpuscular volume (MCV), which increases after months of heavy drinking, with a sensitivity of 24-75% and specificity of 56-96% 1
- Carbohydrate-deficient transferrin (CDT), which becomes elevated after consuming 50-80 grams of alcohol daily for at least 1-2 weeks and remains detectable for 2-4 weeks after cessation of drinking, with a sensitivity of 25%-84% and specificity of 70%-98% 1
Limitations and Clinical Context
It is essential to consider the clinical context when interpreting the results of these serum markers, as some markers like GGT can be affected by non-alcoholic liver disease, medications, or obesity 1.
Recommendation
CDT is the most reliable serum marker for detecting chronic alcohol abuse, and its use should be considered in conjunction with other laboratory tests and clinical evaluation to confirm alcohol consumption 1. In cases where CDT is not available or feasible, GGT and MCV can be used as alternative markers, but their results should be interpreted with caution and in the context of the patient's overall clinical presentation 1. For acute alcohol consumption, direct measurement of blood alcohol concentration is most useful, with levels above 300 mg/dL indicating significant intoxication 1. Phosphatidylethanol (PEth) is an emerging biomarker with high sensitivity and specificity that can detect alcohol use for up to 4 weeks, but its use is not yet widely established in clinical practice 1.
From the Research
Serum Markers for Alcohol Consumption
The serum markers for alcohol (ethanol) consumption are:
- Carbohydrate-deficient transferrin (CDT) 2, 3
- Gamma-glutamyltransferase (GGT) 2, 4, 3
- Other markers such as ethyl glucuronide, phosphatidylethanol, protein-acetaldehyde condensates, and associated autoimmune responses may also be used to detect alcohol consumption 4
Comparison of Serum Markers
- CDT is considered a first-line biological marker to confirm or disprove suspected alcohol misuse 2
- GGT can help differentiate between alcohol abuse and alcohol dependence in cases of high CDT 2
- The combined marker GGT-CDT has been shown to improve the detection of excessive ethanol consumption compared to conventional laboratory markers of alcohol abuse 3
Clinical Applications
- Serum markers can be used as an adjunct to screening for unhealthy alcohol use 5
- Direct measures of alcohol in breath and/or blood can be useful markers of recent use 5
- Biomarkers of alcohol consumption can also be used to detect liver disease and other physical comorbidities associated with alcohol use 4, 6