This episode is about a fairly recent development in TDM and clinical toxicology that has huge potential, which has actually been used for many decades. It was recently the 50th anniversary of the Guthrie method, where dried blood spots are used to screen inborn errors of metabolism in neonatal infants. Thanks to instrumental developments, dried blood spots, and more generally microsampling approaches, have been increasingly applied to quantify a wide range of drug entities. Although these approaches offer plenty of novel opportunities in our field, they are not without challenges and pitfalls.   Our guests today are two of the biggest names in microsampling – and also absolute IATDMCT VIPs and legends. We are joined by our current president, Jan-Willem Alffenaar, and president-elect, Christophe Stove, for deep dive on the topic.   In this episode we hear about: ×      Which Beatle might be the most interesting test subject for microsampling evaluation ×      How low can you go? When does it become a macrosample? ×      Diverse microsampling approaches: dry, wet, different matrices ×      Go robust – or go home ×      Obvious, and not-so-obvious challenges; typical and very novel solutions ×      Clinical, toxicological and research applications: what the innovators are doing, and potential for even greater global impact ×      How many times would you prick your finger in a day? The sweet spot in being informative, but not terrible for patients ×      From the Beatles to ABBA: money, money, money and the place of microsapmpling in health systems   Eight Drugs a Week is supported by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT). The personal views of the hosts and guests do not necessarily reflect the position of the Association.    To join IATDMCT, visit https://www.iatdmct.org/member-join    Subscribe to Eight Drugs a Week on your preferred podcast platform.      About our guests:  Jan-Willem is Professor of Clinical Pharmacology at The University of Sydney, and Chair of Clinical Pharmacy at Westmead Hospital, in Sydney Australia.   Christophe Stove is Professor, and director of the toxicology laboratory, at the Department of Bioanalysis, at Gent University in Belgium.