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 = | *Normal = +/- 14-10 mOsm/L | ||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
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*Glycerol | *Glycerol | ||
*Smaller gaps possible in: | *Smaller gaps possible in: | ||
**Ketoacidosis | **[[ketonemia|Ketoacidosis]] | ||
**[[Lactic acidosis]] | **[[Lactic acidosis]] | ||
**[[Chronic kidney disease]] | **[[Chronic kidney disease]] | ||
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*[[Anion Gap (High)]] | *[[Anion Gap (High)]] | ||
*[[Toxidromes]] | *[[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== | ||
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[[Category:FEN]] | [[Category:FEN]] | ||
[[Category: | [[Category:Toxicology]] | ||
[[Category:Labs]] | |||
Latest revision as of 06:44, 22 March 2026
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
- EtOH
- Ethylene glycol
- Methanol
- Isopropyl alcohol toxicity
- Diethylene glycol
- Propylene glycol
- Mannitol
- Glycerol
- Smaller gaps possible in: