Osmolal or Osmolar Gap: Difference between revisions
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**Normal = (-)14-10 mOsm/L | **Normal = (-)14-10 mOsm/L | ||
== | ====DDx==== | ||
* | *EtOH | ||
**Methanol | *[[Ethylene glycol]] | ||
** | *[[Methanol]] | ||
** | *[[Isopropyl alcohol toxicity]] | ||
* | *[[Diethylene glycol]] | ||
** | *[[Propylene glycol]] | ||
**[[ | *[[Mannitol]] | ||
* | *Glycerol | ||
* | *Smaller gaps possible in: | ||
**Ketoacidosis | |||
**[[Lactic acidosis]] | |||
**[[Chronic kidney disease]] | |||
==Sources== | |||
*Emmett M et al. Serum osmolal gap. UpToDate. Aug 25, 2014. http://www.uptodate.com/contents/serum-osmolal-gap. | |||
==See Also== | ==See Also== | ||
Revision as of 23:26, 18 February 2016
Definitions
- Osmolarity = the total number of particles in solution per liter
- Osmolality = the number of particles per kilogram of solvent
Calculations
Calculated Osm
Calculated Osm = 2 x Na + (glu/18) + (BUN/2.8) + (ethanol/4.6) + (methanol/2.6) + (ethylene glycol/5) + (acetone/5.5) + (isopropanol/5.9)
- Normal = 275-295
Osmolal Gap
- Osmolal Gap = measured osm - calculated osm
- Normal = (-)14-10 mOsm/L
DDx
- EtOH
- Ethylene glycol
- Methanol
- Isopropyl alcohol toxicity
- Diethylene glycol
- Propylene glycol
- Mannitol
- Glycerol
- Smaller gaps possible in:
- Ketoacidosis
- Lactic acidosis
- Chronic kidney disease
Sources
- Emmett M et al. Serum osmolal gap. UpToDate. Aug 25, 2014. http://www.uptodate.com/contents/serum-osmolal-gap.