Application of Volumetric Absorptive Micro Sampling to Measure Multidimensional Anti-Influenza Hemagglutinin IgG Antibodies by mPlex-Flu Assay

Recently, volumetric absorptive microsampling (VAMS) has been used for peripheral blood sampling and analyses in several fields. VAMS ensures accurate sampling by collecting a fixed blood volume (10 or 20 {micro}L) on a volumetric swab in blood spot format, and allows for long-term sample storage. The mPlex-Flu assay is a novel, multidimensional assay that measures the concentration of antibodies against multiple influenza virus hemagglutinins simultaneously strains with a small volume of serum (less than 5 {micro}L). Here we describe combining these two methods to measure multidimensional influenza antibody activity using a finger-stick and VAMS. In this study, we compared influenza antibody profiles measured from capillary blood obtained with a finger-stick, and venous whole blood collected by traditional phlebotomy from 20 subjects using the mPlex-Flu assay. We found that results with the two sampling methods were virtually identical across all influenza strains within the same subject (mean of R2 =0.9470), and that antibodies remained stable over three weeks when VAMS samples were stored at room temperature and transported using a variety of shipping methods. Additionally, VAMS sampling is an easy and highly reproducible process; when volunteers performed finger stick VAMS at home by themselves, the results of anti-HA antibody concentrations showed that they are highly consistent with sampling performed by study personnel on-site (R2 =0.9496). This novel approach provides advantages for clinical influenza vaccine studies, including ease of sampling, low cost, and high accuracy. We conclude that these methods could provide an accurate and low-cost means for monitoring the influenza virus antibody responses in large population studies.