Highly Sensitive and Specific LC–MS/MS Method to Determine Endogenous Leukotriene B4 Levels in Human Plasma

Aim: To develop a high sensitivity and specific analytical method to measure endogenous levels of leukotriene B4 (LTB4) in human plasma. Methodology: LC–MS/MS and ELISA. Results: An LC–MS/MS method was developed with a sensitivity of 1.0 pg/ml, and within and between batch precision of <16% and <13% RSD, respectively. Conclusion: We have developed a sensitive LC–MS/MS method that can detect endogenous LTB4 in human plasma. The LC–MS/MS method displayed correlation with a commercial LTB4 ELISA when analyzing in ex vivo ionophore-stimulated blood samples. For untreated plasma this correlation was lost. Endogenous LTB4 was shown to be unstable in plasma during storage at -20°C and subject to stereoisomer formation. Neither of the assays could quantify endogenous plasma LTB4 in samples stored for long term.