Osmolal or Osmolar Gap: Difference between revisions

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===Osmolal Gap===
===Osmolal Gap===
*Osmolal Gap = measured osm - calculated osm
Osmolal Gap = measured osm - calculated osm
**Normal = (-)14-10 mOsm/L
*Normal = +/- 14-10 mOsm/L


==DDX==
==Differential Diagnosis==
#Alcohols
*[[EtOH]]
##Methanol
*[[Ethylene glycol]]
##Ethylene glycol
*[[Methanol]]
##Isopropyl
*[[Isopropyl alcohol toxicity]]
#Sugar
*[[Diethylene glycol]]
##Glycerol
*[[Propylene glycol]]
##[[Mannitol]]
*[[Mannitol]]
#Ketones
*Glycerol
##Acetone
*Smaller gaps possible in:
**[[ketonemia|Ketoacidosis]]
**[[Lactic acidosis]]
**[[Chronic kidney disease]]


==See Also==
==See Also==
*[[Anion Gap and Osmolar Gap (High)]]
*[[Anion Gap and Osmolar Gap (High)]]
*[[Anion Gap (High)]]
*[[Toxidromes]]
==External Links==
*[http://www.mdcalc.com/serum-osmolality-osmolarity/ MDCalc - Serum Osmolality/Osmolarity]
*[http://www.mdcalc.com/anion-gap/ MDCalc - Anion Gap]
==References==
<references/>


[[Category:FEN]]
[[Category:FEN]]
[[Category:Tox]]
[[Category:Toxicology]]

Latest revision as of 16:29, 29 September 2019

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

Differential Diagnosis

See Also

External Links

References