An enzymic assay for the specific determination of methanol in serum

This method for the specific determination of methanol in serum is based on the following two reactions: (formula; see text) Alcohol oxidase is not specific: it converts all lower alcohols to their corresponding aldehydes; however, formaldehyde dehydrogenase is specific and thus the transformation of NAD+ to NADH (which is used to monitor the reaction) proceeds only if methanol is originally present in the sample. The method was automated with a Roche COBAS FARA centrifugal analyzer. The calibration curve is linear between 0.6 and 12 mmol/L. The detection limit is about 0.6 mmol/L. The CV is 4.6% for a concentration of 3 mmol/L. When 55 serum specimens known to be free of methanol were supplemented with known amounts of methanol and analyzed by the enzymatic method, the results correlated well (r = 0.987) with the true values, the regression equation being: y = 1.016x + 0.661, where x represents the true values. Results are not affected by other alcohols that may be present in serum, by methanol metabolites, or by some commonly prescribed drugs. The major advantage of this new assay is that it can be used 24 h a day in any clinical chemistry laboratory.