Estimating Serum Levels of Isopropanol and Acetone from the Osmolal Gap

 

Isopropanol = (CH3)2 – CHOH with molecular weight 60.10, with density 0.79 g/mL.

 

Acetone = CH3 – CO – CH3 with molecular weight 58.08

 

Acetone is often formed during the metabolism of isopropyl alcohol.

	1 mg/dL in serum will affect osmolality by	1 mOsm per kg H2O reflects serum levels
acetone	0.18 mOsm per kg H2O	5.5 mg/dL
isopropanol	0.17 mOsm per kg H2O	5.9 mg/dL

 

where:

• 1 mOsm per kg H2O roughly approximates a serum level of 1 mmol/L, or (molecular weight) / 10 mg/dL.