Volumetric absorptive microsampling for profiling of signaling lipids: a comparative analysis with whole blood and dried blood spots

Signaling lipids regulate key physiological and pathological processes, providing insights into disease mechanisms and therapeutic targets. While plasma is the standard biofluid for their analysis, its collection and handling pose challenges, including the need for venous access, immediate processing, and stringent cold-chain transportation to prevent lipid degradation. Volumetric absorptive microsampling (VAMS) has emerged as an alternative to conventional whole blood (WB) and dried blood spot (DBS), yet its suitability for comprehensive signaling lipid profiling, including low-abundance species, remains unexplored. This study evaluated the feasibility of VAMS for profiling diverse signaling lipid classes using a single liquid-liquid extraction (LLE) protocol. Analytical performance was assessed by evaluating precision, LLE recovery, matrix effects, and endogenous metabolite levels across WB, DBS, and VAMS. Short-term stability of VAMS at room temperature was examined over 24h, 48h, and 1 week storage. VAMS demonstrated superior precision compared to DBS while achieving moderate but comparable recoveries. The metabolic profile of VAMS aligned closely to WB, while DBS deviated substantially, demonstrating improved lipid stability in VAMS in the initial 24h period at room temperature. However, extended storage for 1 week introduced significant artifacts, altering metabolome composition and emphasizing the need for stabilization strategies, such as desiccant-assisted storage or antioxidant pretreatment to minimize hydrolytic and oxidative degradation. These findings provide initial evidence supporting VAMS as a feasible and promising alternative to DBS for signaling lipid profiling. Further studies are needed to assess extraction efficiency from the VAMS tip, optimize LLE recovery, and evaluate long-term stability, advancing the applicability of VAMS in lipidomics research.