Medical calculators
Osmolar Gap
Measured - Calculated
For education. Check every result.
Anatium is a study resource, not medical advice. Nothing here is a diagnosis, a prescription or a substitute for a clinician who has seen the patient. Check every number against a current local protocol before it touches anyone, and never act on a result you cannot reproduce yourself.
How it is calculated
Osmolar Gap = Measured - Calculated. Usually under 10. A normal gap does not exclude methanol or ethylene glycol poisoning: late after ingestion the alcohol has been metabolised and the gap closes while a high anion gap acidosis remains. Ethanol is the commonest cause of a raised gap; allow for it (ethanol in mg/dL ÷ 3.7) before blaming a toxic alcohol.
About
The difference between measured and calculated osmolality. A wide gap suggests a toxic alcohol such as methanol or ethylene glycol.
The rest of Anatium
Lessons, flashcards, condition modules, the anatomy lab, clinical cases and the AI study assistant are free, and need an account.
Request access