Plasma osmolality

Plasma Osmolality
Plasma Na+ level	meq/L
Plasma glucose	mg/dl
BUN	mg/dl

P(osm)=2Na+(meq/l) + Glucose(mg/dl)/18 + BUN(mg/dl)/2.8
Plasma Osmolality	mOsmol/kg serum water
Under most physiologic conditions, sodium, urea, and glucose generate the osmotic pressure of blood
Normal range of plasma osmolality: 275-295 mOsmol/kg serum water

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