Accurate reference values are essential for the correct interpretation of laboratory tests and clinical decision-making. Reference values should be established by testing a large number of healthy individuals. The results are then averaged and a range (plus or minus 2 standard deviations of the mean) of ‘normal’ values are established. The reference range of a test may be affected by the age and sex of the patient, and the variation is higher in some tests than in others.  Because of this, reference values should be divided in groups according to age and gender, and ideally also according to ethnicity and geographical region.

5th June 2014 • comment