Review of peer-reviewed manuscripts describing wild and captive nondomestic animal reference intervals and reference values – compliance with recommendations, limitations and strengths

Reference intervals are needed to interpret laboratory data from individual animals with suspected disease and when evaluating population health. Guidelines for generation of reference intervals and general clinical study... [ view full abstract ]

Reference intervals are needed to interpret laboratory data from individual animals with suspected disease and when evaluating population health. Guidelines for generation of reference intervals and general clinical study design are available. Application of these guidelines in nondomestic species manuscripts has been variable. Review reference interval manuscripts involving nondomestic species published in Veterinary Clinical Pathology (VCP) between 2011 and 2015 for adherence to the principles and best practices outlined in published reference interval guidelines. Provide examples of exemplary study design. Manuscripts reporting reference intervals of nondomestic animals published in VCP between 2011 and 2015 were evaluated for overall study design, preanalytic and analytic criteria, statistical approaches, and data presentation. Adherence to principles outlined in guidelines adopted by VCP was assessed as a means to communicate how reference interval generation and presentation could be improved. Twenty-three manuscripts covering a wide range of captive and wild vertebrates were reviewed. Most articles fulfilled several important criteria, but no article complied with all guidelines. Common strengths included an adequate description of the reference population, sample collection (including pursuit and capture), and testing methodology used. Common limitations included the use of non-validated methods for the species described, lack of appropriate partitioning, and use of inappropriate statistical analysis for the number of reference individuals. Inclusion of a citation specifically dealing with the science of appropriate reference interval generation was associated with a higher number of fulfilled criteria. Examples of exemplary study design and data evaluation were provided. Compliance with principles and best practices for generation of nondomestic animal reference intervals is critical. While complete compliance with every principle may not be obtainable in every study design, examples of strong study design and easy to follow recommendations (i.e., checklists) will enable better development and communication of reference interval studies.