An alcohol oxidase dipstick rapidly detects methanol in the serum of mice.

Abstract

BACKGROUND: Patients presenting with ingestions of methanol and ethylene glycol pose a significant challenge to emergency physicians. The decision to initiate antidotal therapy must be made quickly and is currently based on the presence of indirect signs, symptoms, and laboratory tests, because no real-time diagnostic test exists to measure these substances. OBJECTIVES: To determine whether a commercially available ethanol-in-saliva detecting dipstick (ALCO-Screen) would be a reliable and rapid indicator of toxic alcohol presence in the serum of an animal model. METHODS: Fifty mice randomly received intraperitoneal doses of methanol, ethylene glycol, or ethanol to induce serum concentrations of approximately 5-400 mg/dL. Thirty minutes after injection, serum was obtained. Serum was both applied to the dipstick and frozen for definitive concentration determination by gas chromatography. After 2 minutes, dipsticks were evaluated for color change by a blinded observer and photographed to be evaluated by other blinded observers at a later time. RESULTS: All concentrations of methanol > or =5 mg/dL consistently caused a color change on the ALCO-Screen. Ethylene glycol reliably caused a color change at > or =300 mg/dL. There was significant agreement among multiple observers whether or not color change had occurred using the ALCO-Screen. CONCLUSIONS: A commercially available dipstick that uses an alcohol oxidase colorimetric reaction reliably and rapidly detects very low serum concentrations of methanol but not ethylene glycol in this animal model. This color change is easily detected by most observers.