The difference between the measured serum osmolality and the calculated osmolality using the following formula:calculated osmolality=2[Na+(in mmol/l)+glucose(in mmol/l)+urea(in mmol/l)]
It is an aid to the diagnosis of severe anion gap acidoses. The normal range for the difference is ± 10 mOsm/kg. A high osmolar gap is normally due to the presence of acetone, mannitol, or an alcohol.
Subjects: Medicine and Health.