Anion gap: Difference between revisions
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**[[Lithium Toxicity]] | **[[Lithium Toxicity]] | ||
*Increased cationic paraprotein | *Increased cationic paraprotein | ||
* | *Multiple myeloma | ||
**Polyclonal IgG gammopathy | **Polyclonal IgG gammopathy | ||
*Pseudo | *Pseudo | ||
Revision as of 18:32, 14 May 2015
Background
AG = Na - (Cl + HCO3)
Normal Anion Gap = 12+/-4 (8-16)
Cutoffs for "normal" Anion Gap are laboratory and equipment specific. Newer technology and equipment have been shown to measure "low" AG in otherwise normal, healthy people.[1][2]
Elevated Anion Gap
Differential Diagnosis
MUDPILES
- M - Methanol
- U - Uremia
- D - DKA
- P - Paraldehyde
- I - Iron, INH
- L - Lactic acidosis
- E - Ethylene glycol
- S - Salicylates
Also:
- Starvation/ETOH ketoacidosis
- Carbon Monoxide (CO), CN poisoning (incr. lactate)
- Toluene
- Chronic acetaminophen use
Low Anion Gap
Differential Diagnosis
- Lab error
- Decreased "unmeasured" anions
- Hypoalbuminemia
- Increased "unmeasured" cations
- Increased cationic paraprotein
- Multiple myeloma
- Polyclonal IgG gammopathy
- Pseudo
- Severe Hypernatremia (>170 meq/L)
- True conc of Na is underestimated
- Marked hyperlipidemia
- Leads to overestimation of plasma Cl conc)
- Bromide intoxication (e.g. for myasthenia gravis and some herbal medications)
- Machine mistakenly reads Br as Cl
- Severe Hypernatremia (>170 meq/L)
- AG falls by 2.5 meq/L for every 1 g/dL reduction in albumin concentration
See Also
Anion Gap and Osmolar Gap (High)