Laboratory tests for acute alcohol consumption: results of the WHO/ISBRA Study on State and Trait Markers of Alcohol Use and Dependence.

Abstract

The WHO/ISBRA Study on State and Trait Markers of Alcohol Use and Dependence aimed partly to evaluate the overall performance and cross-national validity of traditional and new biological markers of alcohol use and abuse. This article focused on the sensitivity and specificity of ethanol and methanol concentrations in plasma, and the 5-hydroxytryptophol (5HTOL) to 5-hydroxyindole-3-acetic acid (5HIAA) ratio in urine, as laboratory tests to identify acute alcohol consumption. Comparison was made with self-reported drinking levels. Subjects were recruited in Australia, Brazil, Canada, Finland, and Japan. They were interviewed thoroughly about their alcohol consumption habits, by using the standardized WHO/ISBRA Interview Schedule, and were classified into four categories: nondrinkers, light/moderate drinkers, heavy drinkers (> or =210 g ethanol/week for men, and > or =140 g/week for women), or patients who were receiving treatment for alcohol dependence. Ethanol and methanol determinations in plasma were carried out by headspace gas chromatography. Urinary concentrations of 5HTOL and 5HIAA were determined by using gas chromatography-mass spectrometry and high-performance liquid chromatography, respectively. The baseline levels (in nondrinkers) for methanol and the 5HTOL/5HIAA ratio did not differ markedly between the five populations, except for a considerably higher, but probably artifactual, methanol level in the Finnish plasma samples. Moreover, there were no apparent age or sex differences. The urinary 5HTOL/5HIAA ratio was the most, and ethanol the least, sensitive indicator of recent alcohol consumption, and this was true for the different drinking categories as well as for the five study populations. The highest frequency of elevated test results was observed among those classified as heavy drinkers (e.g., 38% were positive for 5HTOL/5HIAA). However, elevated values also were obtained in nondrinkers and in drinking subjects who denied any intake of alcohol within 2 days before the interview and blood/urine sampling, which suggested a low accuracy of self-reports of alcohol consumption in certain individuals. The present investigation demonstrated that plasma ethanol and methanol and urinary 5HTOL/5HIAA provide useful exclusion markers for any study of biological parameters that are affected by previous acute ethanol intoxication. The major advantage of methanol and 5HTOL/5HIAA over ethanol is that they can detect recent alcohol consumption even several hours after the ethanol is no longer measurable. The results suggest that the cutoff limits to be used for these markers are not dependent on the country or population to be studied.