Important considerations for interpreting biochemical tests in childrenBMJ 2018; 361 doi: https://doi.org/10.1136/bmj.k1950 (Published 24 May 2018) Cite this as: BMJ 2018;361:k1950
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Laboratory test interpretation, based on reference intervals and decision limits, remains highly variable and poorly harmonized across laboratories. This leads to a great potential for inappropriate patient care when laboratory test results on the same sample can be interpreted differently depending on the reference interval reported by the laboratory. Several groups have launched initiatives to harmonize reference intervals including the NORIP, the UK Pathology Harmony project 1, the Australasian Harmonised Reference Intervals for Adults (AHRIA) and Australasian Reference Interval for Paediatrics (AHRIP)2 . In Canada, a Working Group on reference interval harmonization has also been initiated to identify the variation in reference intervals being used in clinical practice and establish/recommend practice guidelines on the use of harmonized reference intervals in clinical laboratories across Canada.
Major challenges have been overcome and significant advances have been made in the establishment and wide-spread dissemination of accurately established pediatric reference intervals. However, with the continuously evolving technological and clinical advances, national and international research initiatives need to ensure pediatric reference intervals continuously improve and adapt to the changing environment.
Statistically, reference intervals are defined as the limiting values denoting a specified percentage (typically central 95%) of values from an apparently healthy reference population with 90% confidence. In the central 95% distribution model, the reference limits are determined by calculating the 2.5th and 97.5th percentiles of test results.3 In this case, a total of 5% of values may be interpreted as abnormal or higher risk of disease and require further follow-up and investigation.
1. Berg J, Lane V. Pathology Harmony; a pragmatic and scientific approach to unfounded variation in the clinical laboratory. Ann Clin Biochem 2011;48:195-7.
2. Tate JR, Sikaris KA, Jones GR, Yen T, Koerbin G, Ryan J, Reed M, Gill J, Koumantakis G, Hickman P, Graham P. Harmonising adult and paediatric reference intervals in Australia and New Zealand: an evidence-based approach for establishing a first panel of chemistry analytes. Clin Biochem Rev 2014;35:213-35.
3. Boyd JC. Defining laboratory reference values and de¬cision limits: populations, intervals, and interpretations. Asian J Androl 2010;12:83-90.
Competing interests: No competing interests