Reference Interval harmonization across the GTA


The project team

Khosrow Adeli (Chair), The Hospital for Sick Children (SickKids)

Saranya Arnoldo, William Osler Health System

Daniel Beriault, St. Michael’s Hospital, Unity Health Toronto

Mary Kathryn Bohn, Clinical Chemistry Postdoctoral Fellow, University of Toronto

Davor Brinc, Toronto General Hospital, University Health Network (UHN)

Matthew A. Lafrenière, Sunnybrook Health Sciences Centre

Felix Leung , Mount Sinai Hospital


Harmonization in laboratory medicine from specimen collection to result reporting is critical to ensure consistent and accurate clinical decision-making.

Despite major advances in improving quality assurance and laboratory performance, significant and unwarranted variation in reference intervals continues to exist across laboratories, even those using the same analytical methodology. When reference intervals are not appropriately harmonized and the data supports it, there is an increased risk of misinterpreting test results. This can lead to lack of appropriate follow-up, unnecessary investigations, and/or inappropriate resource utilization.

The implementation of evidence-based harmonized reference intervals for laboratory tests is an essential step towards optimized and standardized patient care.

The Canadian Society of Clinical Chemists (CSCC) Reference Interval Harmonization Working Group (hRI) has recently developed evidence-based guidelines on adult reference intervals and is inviting laboratory professionals in regions across Canada to collaborate to ensure Canada-wide implementation and harmonization of common reference intervals for chemistry and immunoassays. 

We aim to assess the current state of reference interval variation for key chemistry and immunoassays in the Greater Toronto Area and work to facilitate harmonization (when supported by direct and indirect evidence).

We have:

  • Completed a GTA-wide Quality Council Survey, and presented the data to the Quality Council
  • Initiated a reference interval verification study across GTA hospitals; healthy adult samples to be distributed to all centres and tested, once Material Transfer Agreements are signed with all participating hospitals.

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Latest guidelines from the Reference Interval Harmonization working group - coming soon!