Dennis Orton

PhD

Investigator and Clinical Biochemist, BC Children's Hospital

My focus is on doing more with less. If we need to take blood from a child, then take as little as possible. If we need to take a biopsy, can we get both diagnosis and a treatment plan all at once? Combining what we know from many years of research with what we want (accurate diagnosis, treatment options) helps personalize drug treatment regimens and minimize blood collections, all while improving the overall patient experience and providing better outcomes. By working with cutting edge technologies and utilizing the extensive expertise of physicians, pathologists and scientists, we can drive substantial improvement in patient health and wellbeing.

Academic Affiliations

  • Clinical Assistant Professor, , Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia
  • Research Theme: Childhood Diseases
  • Research Group(s): Childhood Cancer and Blood Research; Clinical Pharmacology; Clinical and Community Data, Analytics and Informatics; Rare Diseases

Contact Information

Location

4500 Oak Street, Vancouver, British Columbia, Canada, V6H 3N1

Is It Time to Retire Aldosterone Suppression Testing?

American Journal of Hypertension

Gregory A Kline and Alexander A Leung and Dennis Orton and James MacFarlane and Mark Gurnell

DOI: 10.1093/ajh/hpaf163

04 / 2026

Big data determination and validation of reference range for 24-h urine cortisol by liquid chromatography-mass spectrometry

European Journal of Endocrinology

Kline, G.A. and Venos, E.S. and Campbell, D. and Leung, A.A. and Orton, D.

DOI: 10.1093/ejendo/lvaf054

Nociceptor neurons suppress alveolar macrophage-induced Siglec-F+ neutrophil-mediated inflammation to protect against pulmonary fibrosis

Immunity

Hiroki, C.H. and Hassanabad, M.F. and Defaye, M. and Sarden, N. and Bartlett, A. and Farias, R. and Nguyen, A.P. and Guerrero-Fonseca, I.M. and Yoon, G. and Brown, L. and Ma, C. and Yang, H. and Belke, D. and Hassanabad, A.F. and McCoy, C. and Rosin, N.L. and Orton, D.J. and Fedak, P.W.M. and Vallance, B.A. and Yu, H. and Jacobson, K. and Khan, N. and Altier, C. and Kelly, M.M. and Yipp, B.G.

DOI: 10.1016/j.immuni.2025.05.002

Outcomes After Unilateral Adrenalectomy in Asymmetrical Bilateral Primary Aldosteronism

Hypertension

Grundy, M. and Leung, A.A. and Pasieka, J.L. and Harvey, A. and So, B. and Caughlin, C. and Przybojewski, S. and Orton, D. and Hyrcza, M. and Kline, G.A.

DOI: 10.1161/HYPERTENSIONAHA.125.24849

Advancing Newborn Screening in Washington State: A Novel Multiplexed LC-MS/MS Proteomic Assay for Wilson Disease and Inborn Errors of Immunity

International Journal of Neonatal Screening

Klippel, C. and Park, J. and Sandin, S. and Winstone, T.M.L. and Chen, X. and Orton, D. and Singh, A. and Hill, J.D. and Shahbal, T.K. and Hamacher, E. and Officer, B. and Thompson, J. and Duong, P. and Grotzer, T. and Hahn, S.H.

DOI: 10.3390/ijns11010006

Discordance between adrenal vein sampling and imaging: the role of unilateral cortisol excess

European Journal of Endocrinology

Grundy, M. and Leung, A.A. and Hyrcza, M. and Pasieka, J.L. and Chan, D. and Przybojewski, S.J. and So, C.-B.B. and Orton, D. and Harvey, A. and Kline, G.A.

DOI: 10.1093/ejendo/lvaf019

Confirmatory Testing for Primary Aldosteronism A Study of Diagnostic Test Accuracy

Annals of Internal Medicine

Leung, A.A. and Padwal, R.S. and Hundemer, G.L. and Venos, E. and Campbell, D.J.T. and Holmes, D.T. and Orton, D.J. and So, C.B. and Przybojewski, S.J. and Caughlin, C.E. and Pasieka, J.L. and Rabi, D.M. and Kline, G.A.

DOI: 10.7326/ANNALS-24-03153

Targeted proteomic approach for quantification of collagen type I and type III in formalin-fixed paraffin-embedded tissue

Scientific Reports

Nicole L. Rosin and Tara M. L. Winstone and Margaret Kelley and Jeff Biernaskie and Antoine Dufour and Dennis J. Orton

DOI: 10.1038/s41598-024-68377-9

08 / 2024

Understanding Elevated Vitamin D Measurements to Uncover Hypercalcemia Etiology

Clinical Chemistry

Sajid, U. and Orton, D. and Kaufmann, M. and Jones, G. and Kline, G.A.

DOI: 10.1093/clinchem/hvae044

Increased Lp(a) Workload Volumes Reflect Uptake of the 2021 Canadian Cardiovascular Society Guidelines for Management of Dyslipidemia

Canadian Journal of Cardiology

Orton, D.J. and Gifford, J.L. and Raizman, J.E. and Pearson, G.J. and Tsui, A.K.Y.

DOI: 10.1016/j.cjca.2024.02.019

Distribution of videos demonstrating best practices in preventing hemolysis is associated with reduced hemolysis among nurse-collected specimens in hospitals

Clinical Biochemistry

Lawrence de Koning and Dennis Orton and Isolde Seiden Long and Jessica Boyd and Mark Kellogg and Amid Abdullah and Christopher Naugler and Albert Tsui and Brenda Strange and Dory Glaser

DOI: 10.1016/j.clinbiochem.2023.110632

09 / 2023

Agreement of LC-MS assays for IGF-1 traceable to NIST and WHO standards permits harmonization of reference intervals between laboratories

Clinical Biochemistry

Sally Ezra and Tara M.L. Winstone and R. Singh and Dennis J. Orton

DOI: 10.1016/j.clinbiochem.2023.04.002

06 / 2023

Biological variation in clozapine and metabolite reporting during therapeutic drug monitoring

Clinica Chimica Acta

Wickramarachchi, P. and Boyd, J.M. and Orton, D.J.

DOI: 10.1016/j.cca.2022.04.005

Exosomal proteomic analysis reveals changes in the urinary proteome of rats with unilateral ureteral obstruction

Canadian Journal of Chemistry

Orton, D.J. and Doucette, A.A. and Huang, W.-Y. and MacLellan, D.L.

DOI: 10.1139/cjc-2017-0681

Bone metabolism

Endocrine Biomarkers: Clinicians and Clinical Chemists in Partnership

Kline, G. and Orton, D. and Sadrzadeh, H.

DOI: 10.1016/B978-0-12-803412-5.00004-5

Novel approach to establishing an aldosterone: Renin ratio cutoff for primary aldosteronism

Hypertension

Leung, A.A. and Orton, D.J. and Chin, A. and Sadrzadeh, H. and Kline, G.A.

DOI: 10.1161/HYPERTENSIONAHA.116.08407

One-step extraction and quantitation of toxic alcohols and ethylene glycol in plasma by capillary gas chromatography (GC) with flame ionization detection (FID)

Clinical Biochemistry

Orton, D.J. and Boyd, J.M. and Affleck, D. and Duce, D. and Walsh, W. and Seiden-Long, I.

DOI: 10.1016/j.clinbiochem.2015.09.007

Fasting time and vitamin B12 levels in a community-based population

Clinica Chimica Acta

Orton, D.J. and Naugler, C. and Sadrzadeh, S.M.H.

DOI: 10.1016/j.cca.2016.05.005

Critically high plasma ammonia in an adolescent girl

Clinical Chemistry

Orton, D.J. and Gifford, J.L. and Seiden-Long, I. and Khan, A. and De Koning, L.

DOI: 10.1373/clinchem.2016.259473

Resolubilization of precipitated intact membrane proteins with cold formic acid for analysis by mass spectrometry

Journal of Proteome Research

Doucette, A.A. and Vieira, D.B. and Orton, D.J. and Wall, M.J.

DOI: 10.1021/pr500864a

Reprint of "GELFrEE fractionation combined with mass spectrometry for proteome analysis of secreted toxins from Enteropathogenic Escherichia coli (EPEC)"

Molecular and Cellular Probes

Orton, D.J. and Arsenault, D.J. and Thomas, N.A. and Doucette, A.A.

DOI: 10.1016/j.mcp.2014.01.004

Proteomic analysis of rat proximal tubule cells following stretch-induced apoptosis in an in vitro model of kidney obstruction

Journal of Proteomics

Orton, D.J. and Doucette, A.A. and Maksym, G.N. and MacLellan, D.L.

DOI: 10.1016/j.jprot.2013.11.025

Dual LC-MS platform for high-throughput proteome analysis

Journal of Proteome Research

Orton, D.J. and Wall, M.J. and Doucette, A.A.

DOI: 10.1021/pr400738a

GELFrEE fractionation combined with mass spectrometry for proteome analysis of secreted toxins from Enteropathogenic Escherichia coli (EPEC)

Molecular and Cellular Probes

Orton, D.J. and Arsenault, D.J. and Thomas, N.A. and Doucette, A.A.

DOI: 10.1016/j.mcp.2013.06.004

Proteomic workflows for biomarker identification using mass spectrometry - Technical and statistical considerations during initial discovery

Proteomes

Orton, D.J. and Doucette, A.A.

DOI: 10.3390/proteomes1020109

A universal, high recovery assay for protein quantitation through temperature programmed liquid chromatography (TPLC)

Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences

Orton, D.J. and Doucette, A.A.

DOI: 10.1016/j.jchromb.2013.01.021

The htpAB operon of Legionella pneumophila cannot be deleted in the presence of the groE chaperonin operon of Escherichia coli

Canadian Journal of Microbiology

Nasrallah, G.K. and Gagnon, E. and Orton, D.J. and Garduo, R.A.

DOI: 10.1139/w11-086

Targeted proteomic approach for quantification of collagen subtypes in formalin-fixed paraffin-embedded tissue

This project was established to quantify specific proteins in FFPE tissue. Here we develop our understanding of extracellular matrix protein composition during wound healing and fibrosis. The project was a proof-of-principle application to build targeted protein quantitation methods from FFPE tissues and may be applied to a variety of targets.

Development and evaluation of a NUDT15 phenotyping assay in blood

NUDT15 is an enzyme in the metabolism of thiopurine medications that when deficient, causes significant adverse drug reactions to these medications. Primarily occurring in Asian populations, there are no current methods available to phenotype this enzyme and genotyping is often limited to analyzing a single polymorphism while dozens have been described.

Development of a screening method to predict adverse outcomes in 5-FU chemotherapy

5-Fluorouracil is a chemotherapeutic drug with significant associated toxicity. Similar to the above NUDT15 polymorphism, this project was developed to help predict which patients, if any, may experience toxicity associated with a metabolic enzyme deficiency (DPYD).

Grants

IGF-1 in Treatment of Growth Hormone Deficiency. Funding Source: Pfizer Long-Acting Growth Hormone Research

Our Research

At BC Children’s, we are making discoveries that save lives and transform health care for children in our province and around the world. Our research portfolio includes basic, clinical, population, and public health research.

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