Biological variation of clinical pathology parameters refers to the inherent physiological variation of those parameters that occurs within individuals. Biological variation can be used clinically to interpret results in comparison to prior results from that individual  as well as to determine quality specifications for laboratory equipment. 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. 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.