Background: Although alcohol abuse is prevalent in family practice, the diagnosis is not easily established. Laboratory tests are usually heavily relied on in the diagnostic process.
Methods: The value of laboratory tests for the screening and recognition of problem drinking in family practice is summarized, based on a review of the literature. A distinction is made between studies in selected populations of drinkers and studies in nonselected populations, ie, family practice.
Results: The most sensitive laboratory tests associated with excessive alcohol intake include gamma-glutamyl transferase (GGT), mean corpuscular volume, and the ratio of alanine aminotransferase to aspartate aminotransferase. No single laboratory test or combination of tests is shown to be appropriate for screening. The positive predictive value for GGT is only about 25% in a population that has a 10% prevalence of problem drinking and increases to about 55% in a population that has a 30% prevalence of problem drinking.
Conclusions: Guidelines for the recognition of problem drinking in family practice should include elevated laboratory test values as one of the "alerting factors" for problem drinking, and not as a confirmation of a suspicion of problem drinking. In monitoring treatment response, GGT may be a powerful patient-motivating factor.