Biomarkers help us to measure predisposition to a specific condition, or the presence or progress of a pathological state. Alcohol use disorders are common and having good biological markers that accurately reflect both the degree of drinking and the presence of a genetic predisposition to alcoholism can help in identifying , monitoring and managing alcohol dependence.
Eri Hashimoto et al provides a review of this area in this consensus paper by WFSBP task force. This summary will be around the state markers as they are immediately relevant to clinical practice.
There are no biomarkers that can directly identify alcoholism . We have state markers that can detect the timing and intensity of an individual’s alcohol use.
GGT :(gamma-glutamyltransferase) :Early indicator of chronic heavy drinkers, liver disease. Widely used. Medications that induce the microsomal enzymes and conditions like hepatic congestion ,diabetes and pancreatitis can increase GGT. Half life of GGT is one month.
CDT:(Carbohydrate-Deficient Transferrin): Highly specific to alcohol use. Appears to be the most sensitive and specific single test for detecting more recent moderate to heavy alcohol intake (∼7–10 drinks a day). Test and assay are highly standardized, automated and inexpensive; in many places, it is commonly used . Half life 1s 15 days.CDT is significantly more sensitive than GGT in detecting relapses.
MCV: Sustained and regular excessive drinking is important for elevating MCV levels .It may take several months for changes in drinking to be reflected in MCV levels and hence is generally less useful. High values are maintained for long periods after stopping drinking.
AST and ALT: Are more useful to detect liver disease. AST/ALT ratio is thought to be indicative advanced alcoholic liver disease rather than heavy alcohol consumption. The AST/ALT ratio appears to be a useful index for distinguishing non-alcoholic steato hepatitis (NASH) from alcoholic liver disease (a ratio of <1 suggests NASH and values > 2 are strongly suggestive of alcoholic liver disease.
Others: FAEE (fatty acid ethyl esters) ,WBAA (whole blood-associated acetaldehyde) and MAO-B (monoamine oxidase B) are useful in determining recent alcohol use. EtG (ethyl glucuronide) and ethyl Sulphate are used to determine 24 hr sobriety. FAEE (fatty acid ethyl esters) can differentiate recent heavy drink in a social drinker from a heavy chronic drinker.
Detecting recent consumption?: Ethyl glucuronide (EtG) and ethyl sulfate (EtS), both direct metabolites of ethanol, can indicate even a minor intake of alcohol up to 80 hours after alcohol has been eliminated from the body. Urinary EtG/EtS can potentially monitor relapse in patients in active treatment programs. Phosphatidylethanol (PEth) is another marker whose diagnostic specificity is theoretically 100% with half-life in blood of 4 days.The amount of alcohol consumed highly correlates with the blood concentration of PEth; thus, PEth appears to be a more sensitive indicator of alcohol consumption than traditional alcohol markers. It is a more sensitive bio- marker than serum CDT for the detection of relapse drinking.
Conclusion: State markers differ in their utility. Combining biological markers with per- formance of the alcohol use disorders identification test (AUDIT) questionnaire can be helpful in clinical settings. New markers could be particularly useful in detecting minor relapses in clinical/criminal justice settings.
Summary of the article:
Hashimoto E, Riederer PF, Hesselbrock VM, Hesselbrock MN, Mann K, Ukai W, Sohma H, Thibaut F, Schuckit MA, Saito T. World J Biol Psychiatry. 2013 Dec;14(8):549-64.