Development and validation of methods that enable high-quality droplet digital PCR and hematological profiling data from microvolume blood samples.

This article addresses new experimental methods that optimize two distinct techniques. The first technique, known as droplet digital PCR (ddPCR), is a process where DNA is isolated in oil droplets, cloned and then counted. The second technique is known as hematological profiling, in which various components of blood are counted (e.g., red blood cells, hemoglobin). Although ddPCR is incredibly promising as a research tool, there are a few hurdles that limit its usage. First, as of the time of writing, regulatory bodies (i.e., FDA and EMA) have not published official or standardized guidelines specific for either ddPCR or a closely related technique known quantitative PCR (qPCR). This has been an impetus for scientists to independently adopt and abide by unofficial recommendations for ddPCR and to negotiate with these regulatory bodies without a mutually accepted reference point between the two parties. Second, ddPCR can consume considerable volumes of blood, which can impair overall health; this limits how often samples can be taken, making scientists less effective at tracking how much medicine remains in the bloodstream over time. The new methods in this article use less blood, addressing these concerns and allowing scientists to safely collect blood from subjects more often, while also meeting all regulatory criteria established for similar scientific techniques and following informal and widely agreed upon scientific recommendations. Therefore, this work can serve as an easily adaptable framework for most ddPCR experiments.