Volumetric Absorptive Microsampling in Biomarker Analysis: Insights from Targeted and Rapid Microbore Metabolic Profiling Approaches

Introduction: The aim of the study was to assess the feasibility of volumetric absorptive microsampling (VAMS) in biomarker analysis. Amino acids and biogenic amines were quantified in VAMS Mitra devices, liquid venous blood (blood), and plasma using a LC-MS/MS; additionally, profiled using rapid microbore metabolic profiling (RAMMP).

Methods: Paired finger capillary blood on VAMS, blood, and plasma were collected from eight healthy individuals. For LC-MS/MS, samples were prepared using AccTag derivatization [1] and analyzed using RP chromatography (HSS T3 180 µm, 2.1 mm X 150 mm column; 7.5 min) in ESI+ mode. For RAMMP using LC-QTOF-MS, samples were extracted using methanol protein precipitation; RP chromatography (HSS T3 180 µm, 1 mm X 50 mm column; 3.7 min), ESI+, and DDA modes. Data were analyzed using Skyline, MSDIAL, Simca, and MS-excel.

Results: Comparing the targeted metabolites in the three blood matrices 13 metabolites had a strong correlation (Spearman rank (r_s) > 0.6) between the three blood matrices whilst 15 had an accurate concentration comparison (< 15% mean bias). In RAMMP, blood had 3798 features, VAMS 2342, and plasma 1906. PCA captured discrimination of the three blood metabolic profiles while valid OPLS-DA models confirmed their significance (p < 0.05). Sixteen had their highest abundance in VAMS, 14 in blood, and 18 in plasma.

Highlights: In the targeted analysis, VAMS provided quantitative information on several amino acids and biogenic amines similar to conventional matrices. Concentrations of certain metabolites greatly differed in VAMS compared to conventional matrices which may necessitate the establishment of their reference ranges in this matrix. RAMMP showed adoption of VAMS in biomarker research may be dictated by the target metabolites of a research study since specific metabolites are captured in the different blood matrices.