Physiological determinants of plasma biochemical parameters in horses: A structured review

The biochemical profile of horses is a cornerstone in equine clinical diagnostics, offering valuable insights into health status, disease progression, and physiological adaptation to internal and external stimuli. However, the interpretation of these biochemical parameters is far from straightforward, as they are subject to significant variation influenced by a range of physiological factors. Age, sex, breed, level of physical activity, nutritional condition, and reproductive status can all modulate baseline biochemical values, potentially leading to diagnostic inaccuracies if not properly contextualized. This article provides a comprehensive review of the physiological determinants that affect biochemical markers in horses under non-pathological conditions. By examining how these variables alter key analytes -such as enzymes' activity, metabolites, electrolytes, and hormonal concentrations- the study underscores the necessity of establishing context-specific reference intervals. Furthermore, it advocates an individualized approach to biochemical assessment in equine medicine, emphasizing the importance of integrating physiological context into clinical decision-making, to enhance diagnostic precision and therapeutic outcomes.