The clinical spectrum of chronic alcoholism is an unusual paradox for clinicians. Alcohol use in humans has continued for millennia and moderate amounts of ethanol consumption may actually improve health. However, a subset of drinkers may develop catastrophic complications affecting a multitude of organ systems in the body .
Alcohol use, when excessive or chronic, may lead to a variety of adverse effects including and not limited to hepatic dysfunction, cardiovascular disease, neurological injuries, increased risk for malignancies and unintentional accidents. Moderate alcohol intake is to be avoided if it puts the patient at risk (e.g. while driving a car, during pregnancy etc.). Binge drinking and alcohol abuse are amongst the commonest causes of preventable death in the world.
Light-to-moderate alcohol intake is associated with a decreased incidence of coronary heart disease, while heavy drinking may be a precursor for cardiomyopathy. Also, high levels of alcohol use are associated with an elevated risk of developing hepatitis and cirrhosis, especially in males .
Alcohol use has been linked with an increased risk for multiple cancers, with many studies confirming the association between alcoholism and breast, esophageal, oropharyngeal, laryngeal, colorectal, and hepatocellular malignancies.
The diagnosis of chronic alcoholism is made primarily by a proper evaluation of the patient’s history. Physical examination findings may only be evident once the patient has suffered serious consequences of chronic alcoholism. The laboratory tests for detecting heavy alcohol use have a low sensitivity. Thus, an early diagnosis can be made by taking a careful history of the individual and the deleterious effects of alcoholism may be avoided.
Alcohol biomarkers may be used to determine the presence of heavy alcohol use . Indirect alcohol biomarkers reflect the adverse effects of alcohol on the various organ systems, while the direct alcohol biomarkers include alcohol and its metabolites.
Alcohol is a common cause of macrocytosis, with a mean corpuscular volume (MCV) of 100-110 fL seen in a majority of patients. The serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) may be abnormal. A higher elevation of AST compared with an elevation of ALT is characteristic of alcoholic hepatitis. Gamma-glutamyltransferase (GGT) and carbohydrate-deficient transferrin (CDT) levels are also elevated  . Other indirect biomarkers include salsolinol, total serum sialic acid (TSA), 5-hydroxytryptophol (5-HTOL), and N-acetyl-beta-hexosaminidase (Beta-Hex).
A serum alcohol level during the routine examination greater than 100 mg/dL is a reliable indicator of chronic alcoholism. The other direct biomarkers include ethyl glucuronide (EtG), acetaldehyde, phosphatidylethanol, and fatty acid ethyl esters (FAEE)  .