nice blog Don
there is no doubt that there is sufficient sensitivity in todays tandem mass spectrometry to be able to analyze increasing numbers of important biomarkers on the very small sample sizes obtained from filter paper blood spots, particularly when appropriate internal standards are used. We are not there yet but the paradigm of collecting filter paper samples in pediatric clinical facilities could save on the volume of blood drawn from our smallest patients preventing excessive blood loss by phlebotomy. Also by using chromatographic separation and TMS this could allow for multi-analyte analysis on those small samples just as we do in newborn screening. We could really get big rewards for our efforts.