The Use of Δ Osmolality to Predict Serum Isopropanol and Acetone Concentrations

We investigated whether serum Δ osmolality will predict the total serum concentration of isopropanol and acetone metabolite. Three isopropanol ingestions were monitored by Δ osmolality determinations followed by quantification of serum isopropanol and acetone concentrations. The Δ osmolality was established by routine chemical analysis and standard freezing point depression osmometry. Serum isopropanol and acetone levels were quantified by gas chromatography-head space analysis (GC-HS). Patients were initially suspected of having isopropanol intoxication secondary to an elevated Δ osmolality discrepancy (measured - calculated > 10 mOsm). Serum concentrations versus Δ osmolality were analyzed by linear regression (correlation coefficient r=0.713; p<0.05). The Δ osmolality paralleled and decreased relative to the total low molecular weight of volatile concentration in each case. In emergencies, Δ osmolality may be a screening test to identify rapidly patients at risk for complications associated with isopropanol ingestion when GC-HS is not available.