Reference Intervals (RIs) in veterinary medicine

Reference Intervals (RIs) are necessary in veterinary clinical pathology to provide a data base in order to compare results obtained from healthy versus diseased animals. Data are obtained from laboratory tests and, depending on whether they have a Gaussian or non-Gaussian distribution, are processed through statistical tests to define the RIs. This process begins with a healthy reference population made up of individuals who have been initially chosen based on inclusion or exclusion criteria. It is frequently challenging to have a large number of healthy individuals on which to establish de novo RIs, especially in wild and exotic animals. However, the use of reference intervals in daily clinical practice remains a fundamental instrument for therapeutic and diagnostic decisions, but it must always be accompanied by clinical findings that can confirm the hypothesis.