VAMS combine with molex-Flu to measure the influenza virus specific antibodies

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 $\mu$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 simultaneously strains with a small volume of serum (less than 5 $\mu$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 $R^2$ =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 comparison results of anti-HA antibody concentrations showed that they are highly consistent with sampling performed by study personnel on-site ($R^2$ =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.