Reference ranges are valuable guidelines for the clinician, but they should not be regarded as absolute indicators of health and disease. Reference ranges should be used with caution since values for ‘healthy’ individuals often overlap significantly with values for persons afflicted with disease. In addition, laboratory values may vary significantly due to methodological differences and mode of standardization.

[Kristoffersen K. An improved method for the estimation of small quantities of alkali-resistant hemoglobin in blood. Scand J Clin Lab Invest 1961; 13: 402.]

This reference has been the source of the reference ranges given in this section. In some cases the values are taken from other sources marked by their reference number.

Where possible, the reference ranges for arterial blood have been listed. Reference ranges must be used with caution as they depend on a number of factors, such as sex, age, and normal physiological condition.