A.H. Rebar, DVM, PhD, Diplomate ACVP (Clinical Pathology), Purdue University

Biochemical profiling is defined as the use of multiple blood chemistry determinations to simultaneously assess the health status of various organ systems. Standard chemistry screens may include from 12 to 30 different test results, sometimes making interpretation complex. Some key points include: · A single chemistry test should never be used to assess the total health status of an organ. · The factors affecting a given test result, such as causes of elevation, circulating half-life of the component being measured, and routes of excretion, should be understood. · The interactions between different organ systems and how the interactions can affect various test results should be considered. · Only through the systematic assessment of data can misinterpretation and confusion be avoided. The importance of trending should be considered when conducting biochemical profiles. Trending refers to the evaluation of multiple chemistry panels over time. In healthy animals, trending can be used to recognize subtle changes, and in diseased animals, trending can be used to measure the progress of disease or the response to therapy.

COMMENTARY: This presentation gives a good review of the value of biochemical profiles in monitoring both healthy and ill animals. As the article indicates, the result of any single biochemical test should be interpreted based on the results of other tests on the panel as well as on other laboratory results (including CBC and urinalysis), physical examination findings, and history. Because reference intervals ("normal ranges") are calculated using only 95% of the values obtained from a population of normal animals, it is common for healthy animals to have one or more abnormal test results. The values, however, are usually only slightly outside of the reference interval. Results markedly outside of the reference interval usually indicate a pathologic condition.