Abstract
Not all metabolic acidosis is associated with an elevated chloride replacing the low bicarbonate concentration. When other acids, usually non-Cl organic acids are introduced into the blood an “Anion Gap” metabolic acidosis exists. The serum anion gap is calculated as [Na+] – ([Cl−] + [HCO3−]) = Unmeasured anions − Unmeasured cations. The normal gap is mostly due to negatively charged albumin: (Normal range: 8–12 meq/l) as the unmeasured anions, since albumin is usually reported in grams per liter (not meq/l). For diagnostic purposes, calculating the serum anion gap allows determination of coexisting acid–base processes in a patient. Assuming a 1:1 fall in bicarbonate compared with rise in anion gap in a usual gap acidosis, one can compare the Δ anion Gap/ΔHCO3−: Δ gap = observed anion gap − normal anion gap and the Δ HCO3− = normal HCO3− − observed HCO3−. A ratio of 1 suggests a simple anion gap acidosis; if <1 a superimposed non-gap acidosis is lowering HCO3− and if >1 a superimposed metabolic alkalosis is raising HCO3−. Comparing the anion gap and osmolar gap can narrow the differential diagnosis to include toxic alcohol ingestions with acidic metabolites such as ethylene glycol and methanol. Not all metabolic acidosis is associated with an elevated chloride replacing the low bicarbonate concentration. When other acids, usually non-Cl organic acids are introduced into the blood an “Anion Gap” metabolic acidosis exists. This review will consider the generation of anion-gap acidoses through case discussions.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
Funding
This article is published as part of a supplement sponsored by NuOmix-Research k.s. The conference was financially supported by Protina Pharmazeutische GmbH, Germany and Sirius Pharma, Germany, and organized by NuOmix-Research k.s. Neither company had any role in writing of the manuscript.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The author has declared no competing interests.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Seifter, J.L. Anion-gap metabolic acidemia: case-based analyses. Eur J Clin Nutr 74 (Suppl 1), 83–86 (2020). https://doi.org/10.1038/s41430-020-0685-5
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41430-020-0685-5
This article is cited by
-
The Effects of Lead and Cadmium Co-exposure on Serum Ions in Residents Living Near a Mining and Smelting Area in Northwest China
Biological Trace Element Research (2022)
-
Methyl-salicylate/paracetamol
Reactions Weekly (2020)