Eliminating Volumetric Haematocrit Bias Associated with DBS Sub-Punch Workflows Using a Novel Microsampling Device which Absorbs a Fixed Volume of Blood.

Dried blood spot (DBS) cards are routinely used as simple, low cost microsampling tools for clinical and preclinical applications. In general, when using a typical DBS workflow, the dried blood sample is sub-punched to generate a disk which is assumed to contain a fixed volume of blood. This sub-punch is then extracted for analysis. The drawback of this approach is that viscosity of the collected blood will influence the extent to which the blood spot spreads across the DBS card. Thus, fixed volumes of blood which have different haematocrit (HCT) levels will generate different sized spots on the DBS card, and the resulting sub-punches will therefore contain different volumes of blood. This can lead to assay bias as a function of blood haematocrit levels. Here we describe a novel microsampling device that eliminates the volumetric assay bias seen with conventional DBS sub-punch sampling. [ABSTRACT FROM AUTHOR]