Ver el código de «Anion gap»

==Background==
A normal gap is 12 +/- 4 (i.e. 8 to 16).  The anion gap is the difference between measured cations and measured anions in serum.  This difference does not  reflect a true disparity between positive and negative charges, given that serum actually 
is electrically neutral when all serum cations and anions are measured.  Rather, the anion gap is a measurement artifact resulting 
from the fact that only certain cations and anions are routinely measured.  Anion gap metabolic acidosis is secondary to the addition of endogenous or exogenous acid
*AG = Na - (Cl  +  HCO3)
*Normal Anion Gap = 12+/-4 (8-16)
*12-20 mEq/L when including K+
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.<ref>Jurado RL, del Rio C, Nassar G, Navarette J, Pimentel JL Jr. "Low anion gap." South Med J. 1998;91(7):624</ref><ref>Winter SD, Pearson JR, Gabow PA, Schultz AL, Lepoff RB. "The fall of the serum anion gap." Arch Intern Med. 1990;150(2):311</ref>

==Elevated Anion Gap==
===Differential Diagnosis===
MUDPILES
*M - [[Methanol]], [[metformin]]
*U - [[Uremia]]
*D - [[Diabetic Ketoacidosis (DKA)|DKA]]
*P - Paraldehyde, phenformin
*I - [[Iron Toxicity|Iron]], INH, [[ibuprofen]] (large ingestions)
*L - [[Lactic acidosis]]
*E - [[Ethylene glycol]]
*S - [[Aspirin (Salicylate) Toxicity|Salicylates]]

Also:
*Starvation/[[Alcoholic ketoacidosis|ETOH ketoacidosis]]
*[[Carbon monoxide toxicity| Carbon Monoxide (CO)]], [[Cyanide|CN poisoning]] (increased [[lactate]]), [[colchicine]]
*Toluene
*Chronic [[acetaminophen]] use

KILR
*K – [[Ketoacidosis]] - ([[Diabetic ketoacidosis (DKA)|diabetic]], [[Alcoholic ketoacidosis|Alcohol]], Starvation)
*I – [[Toxicology (Main)|Ingestion]] - ([[Aspirin (Salicylate) Toxicity|Salicylates]], [[Acetaminophen]], [[Methanol]], [[Ethylene glycol]], [[Carbon monoxide toxicity|CO]], [[Cyanide|CN]], [[Iron toxicity|Iron]], [[INH toxicity|INH]])
*L – [[Lactic acidosis]] - (infection, hemorrhage, hypoperfusion, [[Alcohol]], [[Metformin]])
*R – Renal - ([[Uremia]])

==Low Anion Gap==
===Differential Diagnosis===
*Lab error
*Decreased "unmeasured" anions
**[[Hypoalbuminemia]]
*Increased "unmeasured" cations
**[[Hyperkalemia]]
**[[Hypercalcemia]]
**[[Hypermagnesemia]]
**[[Lithium Toxicity]]
*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 toxicity]] (e.g. for [[myasthenia gravis]] and some herbal medications)
***Assay mistakenly reads Br as Cl
***May have negative anion gap
**Elevated serum iodide

*AG falls by 2.5 meq/L for every 1 g/dL reduction in albumin concentration

==See Also==
*[[Anion Gap and Osmolar Gap (High)]]
*[[Anion Gap (High)]]
*[[Osmolal or Osmolar Gap]]
*[[Toxidromes]]
*[[Acidosis]]

==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:Toxicology]]
[[Category:Critical Care]]