Physiotypic variations lead to variations within the normal range for red blood cells and haemoglobin levels in a healthy human population: An evaluation using generalised additive modelling and hierarchical structure analysis.

This study provides a proof of principle, that haematological parameters are dependent on physiotypic variation, within the normal ranges in a healthy population. It may also be noted that there is a definitive influence of height, weight and age on normal ranges and stratification by these factors might therefore make reference intervals narrower, in turn, possibly allowing more precise clinical decisions based on the complete blood count (CBC).