This version was machine-translated from German and has not been medically reviewed. The authoritative version is the German version.
Osmolal Gap
Measured minus calculated osmolality – with ethanol correction (Purssell 2001)
Calculation aid for healthcare professionals: the calculator reproduces what the sources cited assign to the inputs. Clinical assessment and every treatment decision remain with the treating physician. Inputs and results are not stored.
Frequently asked questions
Osmolal Gap: What does this calculator compute?
Calculates the osmolal gap as the difference between measured and calculated osmolality (2 × Na + glucose/18 + BUN/2.8), optionally after subtracting the ethanol contribution (ethanol mg/dl ÷ 3.7); normal < 10 mOsm/kg.
Osmolal Gap: Which sources is this calculator based on?
Rasouli M: Basic concepts and practical equations on osmolality: Biochemical approach (Clin Biochem 49:936–941) (2016); Purssell RA, Pudek M, Brubacher J, Abu-Laban RB: Derivation and validation of a formula to calculate the contribution of ethanol to the osmolal gap (Ann Emerg Med 38:653–659) (2001)