Biological variation of clinical pathology measurands refers to the inherent physiological variation of those measurands that occurs within individuals. Biological variation can be used clinically to determine subject-based reference values (reference change values) as an alternative to population-based reference intervals as well as to determine quality specifications for laboratory equipment.

vetbiologicalvariation.org is an independent, not-for-profit website that has been established by a cross-disciplinary committee of veterinary clinical pathologists, internists and epidemiologists who have shown an interest (and in many cases published) in this area.

vetbiologicalvariation.org aims to bring together in one place all peer-reviewed literature relating to veterinary clinical pathology biological variation and present this data. Additionally, guidelines have been established for future studies in this area. Our friends at VIN have designed an online reference change value calculator that can be accessed from this site.