Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2017 Dec;3(4):149-159.
doi: 10.1159/000479279. Epub 2017 Sep 1.

Review of the Diagnostic Evaluation of Normal Anion Gap Metabolic Acidosis

Kenrick Berend  1
Affiliations
Review

Review of the Diagnostic Evaluation of Normal Anion Gap Metabolic Acidosis

Kenrick Berend. Kidney Dis (Basel). 2017 Dec.

Abstract

Background: Normal anion gap metabolic acidosis is a common but often misdiagnosed clinical condition associated with diarrhea and renal tubular acidosis (RTA). Early identification of RTA remains challenging for inexperienced physicians, and diagnosis and treatment are often delayed.

Summary: The presence of RTA should be considered in any patient with a high chloride level when the CL-/Na+ ratio is above 0.79, if the patient does not have diarrhea. In patients with significant hyperkalemia one should evaluate for RTA type 4, especially in diabetic patients, with a relatively conserved renal function. A still growing list of medications can produce RTA.

Key messages: This review highlights practical aspects concerning normal anion gap metabolic acidosis.

Keywords: Acidosis; Anion gap; Hyperchloremia; Osmolal gap; Renal-tubular acidosis; Urine pH.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1
Gamblegram: balance between anions and cations in plasma.
See this image and copyright information in PMC

References

    1. Berend K, de Vries AP, Gans RO. Physiological approach to assessment of acid-base disturbances. N Engl J Med. 2015;372:195. - PubMed
    1. Kraut JA, Madias NE. Serum anion gap: its uses and limitations in clinical medicine. Clin J Am Soc Nephrol. 2007;2:162–174. - PubMed
    1. Roberts WL, Johnson RD. Serum anion gap. Has the reference value really fallen? Arch Pathol Lab Med. 1997;121:568–572. - PubMed
    1. Sadjadi SA, Manalo R, Jaipaul N, McMillan J. Ion-selective electrode and anion gap range: What should the anion gap be? Int J Nephrol Renovasc Dis. 2013;6:101–105. - PMC - PubMed
    1. Farwell WR, Taylor EN. Serum anion gap, bicarbonate and biomarkers of inflammation in healthy individuals in a national survey. CMAJ. 2010;182:137–141. - PMC - PubMed