In recent years, the use of dried matrix spots (DMS), in general, and of dried blood spots (DBS), in particular, has substantially increased. These clinical specimens are formed when depositing a few droplets of the biological fluid subject to analysis (e.g., blood) onto a suitable clinical filter paper. While this minimally invasive sampling technique was already proposed many years (1963) ago by Guthrie and Susi to screen newborns for phenylketonuria, in the last decade its use has been applied to many other situations.
The reasons for this are related to the different benefits that such strategy brings about. In addition to the small sample requirement (a few droplets) and the minimally invasive nature of this strategy, which is essential for instance when the target is a newborn, since venipuncture is not suitable for them, there are other significant benefits. In fact, it has been demonstrated that the resulting DBS, precisely since water has been removed, it is much more stable and several can be stored for at least months without the need of special refrigerators, therefore making DBS ideal for biobanks. Also, when screening of large areas in less developed countries is intended, this is a very attractive approach, as it enables sampling a large population with a mobile station and send the DBS to the lab by mail. In fact, for patients with chronic disorders, it is possible to obtain the DBS in their own houses and send them to the lab as well.
Despite all these benefits, there are some challenges associated with the analysis of these types of samples, particularly when quantitative information is aimed at. In this presentation, different ways to produce DBS will be introduced and compared, with the ultimately goal of obtaining elemental information.