Effective serum osmolality is:
Total osmolality = (2x plasma ) + (glucose/18) + (BUN/2.8) Effective osmolality or tonicity = (2x plasma ) + (glucose/18) The in plasma is measured as the nitrogen in the urea molecule, or blood urea nitrogen (BUN). Effective osmolality does not include BUN because urea is an ineffective osmole. If plasma is taken as 141 meq/L; then 2 x 141 = 282. Considering the normal plasma glucose, Normal serum osmolality: would fall in the range 275 to 290 mOsm/L. Effective serum osmolality:would be 270-285 mOsm/L.
255-270 mosm/L
270-285 mosm/L
285-300 mosm/L
300-325 mosm/L
Excretory System (Kidney, Bladder) Acid-Base Balance