Characteristics of a New Urine, Serum, and Saliva Alcohol Reagent Strip

We have tested an ethanol reagent strip developed at the Addiction Research Foundation of Ontario. Alcohol dehydrogenase and nicotinamide adenine dinucleotide, in the presence of pyrazole, react with ethanol to yield acetaldehyde plus reduced nicotinamide adenine dinucleotide. The latter reduces iodonitrotetrazolium chloride in the presence of diaphorase, generating an intense red color. The rate of color development is proportional to the concentration of ethanol. Color is compared at a specific time against a calibrated color scale ranging from green (negative) to red, representing alcohol concentrations of 0, 25,50, 100, 200, and 400 mg/dI(0‐0.4%; 0–87 mmol/liter). We were able to interpolate the color observed between the calibrated blocks. When tested on urine, serum/plasma, and saliva, ethanol concentration determined by the reagent strip correlates well with ethanol concentration as determined by gas chromatography or by automated enzymatic analysis (r= 0.92–0.98, p < 0.001; slope 0.83–1.16). The reagent strip was shown to be used appropriately by nonexperienced individuals following a 1‐min explanation (reagent strip values, r= 0.92; p < 0.001, slope = 0.97, versus gas chromatography). The reagent strip does not react with methanol (wood alcohol), isopropanol (rubbing alcohol), and ethylene glycol (antifreeze) often found in accidental poisonings. In 379 clinical samples obtained without exclusion criteria from 12 hospital emergency rooms and a liver clinic, the sensitivity of the reagent strip in detecting ethanol was 98%. Specificity was 99%. The reagent strip was found to have virtually unlimited stability under refrigeration (4°C) and to be stable for 3 to 4 months at room temperature (22‐23°C). The reagent strip should be valuable in a number of clinical settings in which rapid assessment of alcohol intoxication or of alcohol consumption, using either of the biological fluids (urine/serum/saliva), is wanted and in which a specific and sensitive method to determine alcohol requiring no instrumentation is needed.