Calculations must be re-checked, shouldn't be used alone for patient care, and don't substitute for professional judgment. See our full disclaimer.
Calculates expected serum osmolarity, for comparison to measured osmolarity to detect unmeasured compounds in the serum.
Serum Osmolality (US) = (2 * (Na) + (BUN / 2.8) + (glucose / 18) + (ethanol/4.6)
If values are in SI units, these are already molar (mmmol/L for example), so these do not need to be divided by their molecular weight.
Calculations must be re-checked and should not be used alone to guide patient care nor should they substitute for clinical judgement. disclaimer