Osmolality
Authors: Keith D. Wrenn
Journal: Annals of Internal Medicine (1991)

Letters15 February 1991OsmolalityKeith D. Wrenn, MDKeith D. Wrenn, MDSearch for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-114-4-337 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptTo the Editors: I am concerned by four problems in the article by Schelling and colleagues (1). First, the formula used to calculate osmolality is misleading. The formula used by most clinicians is as follows (2, 3):When ethanol is included, the formula is as follows (2, 3):If a correction for the molecular weight of urea nitrogen and glucose is not made and values measured in milliequivalents per litre or millimols per litre are plugged into the formula espoused by Schelling, osmolality is markedly overestimated. This formula may represent a typographic omission; if not, its use should be better...References1. Schelling J, Howard R, Winter S, and Linas S. Increased osmolal gap in alcoholic ketoacidosis and lactic acidosis. Ann Intern Med. 1990;113:580-2. LinkGoogle Scholar2. Smithline N and Gardner K. Gaps—anionic and osmolal. JAMA. 1976;236:1594-7. CrossrefMedlineGoogle Scholar3. Emmett M and Narins R. Clinical use of the anion gap. Medicine (Baltimore). 1977;56:38-74. CrossrefMedlineGoogle Scholar4. Dorwart W and Chalmers L. Comparison of methods for calculating serum osmolality from chemical concentrations, and the prognostic value of such calculations. Clin Chem. 1975;21:190-4. CrossrefMedlineGoogle Scholar5. Jacobsen D, Bredesen J, Eide I, and Ostborg J. Anion and osmolal gaps in the diagnosis of methanol and ethylene glycol poisoning. Acta Med Scand. 1982;212:17-20. CrossrefMedlineGoogle Scholar1. Schelling J, Howard R, Winter S, and Linas S. Increased osmolal gap in alcoholic ketoacidosis and lactic acidosis. Ann Intern Med. 1990;113:580-2. LinkGoogle Scholar2. Glasser L, Sternglanz P, Combie J, and Robinson A. Serum osmolality and its applicability to drug overdose. Am J Clin Pathol. 1973;60:695-9. CrossrefMedlineGoogle Scholar3. Jacobsen D, Bredesen J, Eide I, and Ostborg J. Anion and osmolal gaps in the diagnosis of methanol and ethylene glycol poisoning. Acta Med Scand. 1982;212:17-20. CrossrefMedlineGoogle Scholar4. Dorwart W and Chalmers L. Comparison of methods for calculating serum osmolality from chemical concentrations, and the prognostic value of such calculations. Clin Chem. 1975;21:190-4. CrossrefMedlineGoogle Scholar This content is PDF only. To continue reading please click on the PDF icon. Author, Article, and Disclosure InformationAuthors: Keith D. Wrenn, MDAffiliations: University of Rochester Medical Center Rochester, NY 14642 PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics Cited byComparison of measured and calculated osmolality levelsBasic concepts and practical equations on osmolality: Biochemical approachComparison of methods for calculating serum osmolality: multivariate linear regression analysisExtracorporeal therapies for acute intoxications 15 February 1991Volume 114, Issue 4Page: 337-338KeywordsEthanolGlucoseUrea ePublished: 1 December 2008 Issue Published: 15 February 1991 PDF downloadLoading ...