The use of delta osmolality to predict serum isopropanol and acetone concentrations

We investigated whether serum delta osmolality will predict the total serum concentration of isopropanol and acetone metabolite. Three isopropanol ingestions were monitored by delta osmolality determinations followed by quantification of serum isopropanol and acetone concentrations. The delta 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 delta osmolality discrepancy (measured - calculated > 10 mOsm). Serum concentrations versus delta osmolality were analyzed by linear regression (correlation coefficient r = 0.713; p < 0.05). The delta osmolality paralleled and decreased relative to the total low molecular weight of volatile concentration in each case. In emergencies, delta osmolality may be a screening test to identify rapidly patients at risk for complications associated with isopropanol ingestion when GC-HS is not available.