Tailored Extraction Procedure Is Required To Ensure Recovery of the Main Lipid Classes in Whole Blood When Profiling the Lipidome of Dried Blood Spots.

The use of dried blood spots has increased in research and clinical settings recently, particularly in field studies and screening, but comprehensive acyl-specific lipidomic profiling of dried blood spots has yet to be examined. An untargeted ultrahigh-performance liquid chromatography-tandem mass spectrometry method was adapted for the analysis of lipid extracts from human whole blood samples and dried blood spots collected on chromatography paper. Lipid recoveries were examined after different durations of exposure to extraction solvents (chloroform/methanol), physical disruption (homogenization or sonication) of the paper containing the dried blood spots, and acidification of extraction solvents. We demonstrated that comprehensive untargeted profiles can be obtained from dried blood spot samples that are comparable with whole blood for several species of lipids including phosphatidylcholine, lyso-phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, triacylglycerol, and cholesteryl ester. However, homogenization of the dried blood spots, followed by a 24 h exposure to solvents, and extraction with an acidic buffer (0.2 M NaHPO4 + 0.1 M hydrochloric acid) was required. Dried blood spots can be used for comprehensive, untargeted lipidomics of the most abundant lipid species in whole blood, but additional sample processing steps are required.