Abstract Background Ethanol use can lead to many health and socio-economic problems. Early identification of risky drinking behaviors helps provide timely clinical and social interventions. Laboratory testing of biomarkers of ethanol use supports the timely identification of individuals with risky drinking behaviors. This review provides an overview of the utility and limitations of ethanol biomarkers in the clinical laboratory. Content Direct assessment of ethanol in tissues and body fluids has limited utility due to the pharmacokinetics of ethanol. Therefore, the evaluation of ethanol use relies on nonvolatile metabolites of ethanol (direct biomarkers) and measurement of the physiological response to the toxic metabolites of ethanol (indirect biomarkers). Ethanol biomarkers help monitor both chronic and acute ethanol use. The points discussed here include the clinical utility of ethanol biomarkers, testing modalities used for laboratory assessment, the specimens of choice, limitations, and clinical interpretation of results. Finally, we discuss the ethical principles that should guide physicians and laboratorians when using these tests to evaluate alcohol use. Summary Indirect biomarkers such as carbohydrate-deficient transferrin, mean corpuscular volume, and liver enzymes activities may suggest heavy ethanol use. They lack sensitivity and specificity for timely detection of risky drinking behavior and have limited utility for acute ethanol use. Direct biomarkers such as ethyl glucuronide, ethyl sulfate, and phosphatidylethanol are considered sensitive and specific for detecting acute and chronic ethanol use. However, laboratory assessment and result interpretation lack standardization, limiting clinical utility. Ethical principles including respect for persons, beneficence, and justice should guide testing.