Serum Osmolality/Osmolarity

Calculates expected serum osmolarity, for comparison to measured osmolarity to detect unmeasured compounds in the serum.

Na
BUN/Urea
Glucose
Ethanol
Serum Osmolality
Normal serum osmolality = 285-295 mOsm/kg
Normal Serum Osm Gap (Measured-Calculated) is -14 to +10.

Serum Osmolality (US) = (2 * (Na) + (BUN / 2.8) + (glucose / 18) + (ethanol/4.6); SI units ares all molar, so no need to divide by 2.8 or 18 or 4.6.









The NNT : Quick Summaries of Evidence-Based Medicine