An Analytical Perspective on Liquid Chromatography-Mass Spectrometry Methods for the Analysis of Bile Acids in Human Blood Samples

Bile acids (BA) are traditionally recognized as detergents that facilitate lipid and glucose digestion and homeostasis. More recently, they have emerged as signaling molecules with the ability to influence metabolic processes via the gut-brain axis. BA are implicated in a wide range of diseases and conditions, including gastrointestinal, hepatobiliary, metabolic, cardiovascular, and neurological disorders. Accurate quantification of total bile acids (TBA) and individual BA species is essential for understanding their roles in health and disease. Liquid chromatography coupled with mass spectrometry (LC-MS) offers the sensitivity and selectivity required to detect these metabolites at trace levels in human blood samples. This systematic review critically examines validated LC-MS methodologies for BA analysis in human blood, focusing on studies published between January 2010 and April 2024. It highlights experimental designs, validation criteria, and methodological differences, aiming to inform the development of standardized analytical protocols. By addressing current gaps and emphasizing comprehensive analytical validation, this review seeks to enhance the reliability of BA quantification and support future biomarker discovery and clinical applications.