Anion gap: Difference between revisions
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***Leads to overestimation of plasma Cl conc)
***Leads to overestimation of plasma Cl conc)
**Bromide intoxication (e.g. for [[myasthenia gravis]] and some herbal medications)
**Bromide intoxication (e.g. for [[myasthenia gravis]] and some herbal medications)
***Machine mistakenly reads Br as Cl
***Assay mistakenly reads Br as Cl


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

Revision as of 12:57, 8 June 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

Also:

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)
      • Assay mistakenly reads Br as Cl
  • AG falls by 2.5 meq/L for every 1 g/dL reduction in albumin concentration

See Also

Anion Gap and Osmolar Gap (High)

Sources

  1. ↑ Jurado RL, del Rio C, Nassar G, Navarette J, Pimentel JL Jr. "Low anion gap." South Med J. 1998;91(7):624
  2. ↑ Winter SD, Pearson JR, Gabow PA, Schultz AL, Lepoff RB. "The fall of the serum anion gap." Arch Intern Med. 1990;150(2):311
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