Direct Processing and Storage of Cell-free Plasma using Dried Plasma Spot Cards



Plasma separation cards represent a viable approach for expanding testing capabilities away from clinical settings by generating cell-free plasma with minimal user intervention. These devices typically comprise a basic structure of plasma separation membrane (PSM), unconstrained porous collection pad, and utilize either (i) lateral or (ii) vertical fluidic pathways for separating plasma. Unfortunately, these configurations are highly susceptible to (i) inconsistent sampling volume due to differences in patient hematocrit or (ii) severe contamination due to leakage of red blood cells (RBCs) or release of hemoglobin (i.e., hemolysis). Herein, we combine the enhanced sampling of our previously reported patterned dried blood spot (pDBS) cards with an assembly of porous separation materials to produce a patterned dried plasma spot (pDPS) card for direct processing and storage of cell-free plasma. Linking both vertical separation and lateral distribution of plasma yields discrete plasma collection zones that are spatially protected from potential contamination due to hemolysis and an inlet zone enriched with blood cells for additional testing. We evaluate the versatility of this card by quantitation of three classes of analytes and techniques including: (i) soluble transferrin receptor by enzyme-linked immunosorbent assay (ELISA), (ii) potassium by inductively coupled plasma atomic emission spectroscopy (ICP-AES), and (iii) 18S rRNA by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). We achieve quantitative recovery of each class of analyte with no statistically significant difference between dried and liquid reference samples. We anticipate that this sampling approach can be applied broadly to improve access to critical blood testing in resource limited settings or at the point of care.


Supplementary material

Supporting Information for Baillargeon et al.
Materials and Methods. Detailed schematic of patterned TFN layer. Representative images of pDPS cards after removing separation materials. Controlled evaporation improves quantification of soluble transferrin receptor protein. Estimation of sample volume in pDPS cards. Effect of recovery method from pDPS cards for quantitation of potassium. Analysis of amplicons from 18S rRNA from white blood cells. Primers used in RT-qPCR.