My watch list  

Osmolal gap

Osmolal gap is the difference between measured serum osmolality and calculated serum osmolality.

Additional recommended knowledge

It is typically calculated as: OG = measured serum osmolality - (2 X serum sodium + [[blood sugar|serum glucose]/18] + serum [[urea]/2.8/])


  • 2 X serum sodium + serum glucose + serum urea = the calculated serum osmolality and all measures are in mmol/L.
  • OG = osmolal gap

In US customary units the calculated osmolarity is: ( 2 x sodium ) + glucose/18 + BUN/2.8.

A normal osmolal gap is < 12 mmol/L.

Causes of an elevated osmolal gap are numerous. Noted causes are:

See also

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Osmolal_gap". A list of authors is available in Wikipedia.
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE