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Research history

Roy A. Purssell

Research profile. Roy A. Purssell is not affiliated with or endorsed by MedMaths.

Emergency medicine and medical toxicology

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Overview

Roy A. Purssell, MD, FRCPC, ABEM, FACMT, is a Professor in the University of British Columbia Department of Emergency Medicine and has served as a medical lead of the BC Drug and Poison Information Centre. He trained in emergency medicine and medical toxicology. In 2001, Purssell and colleagues prospectively derived and validated an empirical relationship for ethanol's contribution to the osmolal gap: ethanol in mg/dL divided by 3.7, or approximately 1.25 times ethanol in mmol/L. MedMaths links this profile specifically to that ethanol-adjustment evidence; it does not imply authorship of the base calculated-osmolality equation.

Qualifications
FRCPC, ABEM, FACMT
Specialty
Emergency medicine and medical toxicology
Institutions
University of British Columbia Department of Emergency Medicine; BC Drug and Poison Information Centre

Evidence trail

Original research

Purssell RA, Pudek M, Brubacher J, Abu-Laban RB. Derivation and validation of a formula to calculate the contribution of ethanol to the osmolal gap. Annals of Emergency Medicine. 2001;38(6):653-659

DOI: 10.1067/mem.2001.119455View on PubMed (PMID 11719745)

Evidence source for the empirical ethanol contribution used as one optional ethanol-adjustment method on the MedMaths osmol-gap calculator. The study was co-authored by Purssell, Pudek, Brubacher and Abu-Laban; the Purssell researcher profile does not imply sole authorship.

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Each link below has a recorded relationship type. It may represent formula authorship, co-authorship, historical foundation or interpretation research; none implies endorsement or involvement from Roy A. Purssell.

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Serum Osmolality Calculator

Calculate serum osmolality from sodium, glucose and urea, with optional osmol gap calculation.

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Calculated Serum Osmolality and Osmol Gap Explained

Understand directly measured vs calculated serum osmolality, effective osmolality/tonicity, what the osmol gap represents, why formulas and ethanol coefficients change the result, and why the gap must be interpreted as a clue rather than a diagnosis.

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About this profile

This profile summarizes the published work and draws on the original publications above and verified external sources. It isn't a calculator or clinical advice. Roy A. Purssell isn't affiliated with MedMaths and hasn't endorsed it. Anything we couldn't confirm is left blank, not estimated.

pubmed.ncbi.nlm.nih.gov emergency.med.ubc.ca emergency.med.ubc.ca

Reference data verified: 2026-08-24

See the methodology and editorial policy for the wider sourcing process.

Profile at a glance

Formulas
0
Publications
1
Verified links
1

Research focus

Medical toxicologyOsmolal gapEthanol and serum osmolalityEmergency medicine

Research profiles

  • UBC Department of Emergency Medicine profile

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Portraits appear only when reuse rights are verified, and calculator links only when the relationship is recorded.

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