Genetic analyses are informative but do not fully explain phenotypic diversity, particularly with respect to clot formation-lysis behavior.<h4>Objectives</h4>This study developed a novel plasma-based functional assay for exploratory characterization of integrated clot formation-lysis kinetics in congenital dysfibrinogenemia.<h4>Methods</h4>The Clauss fibrinogen assay was modified by supplementing recombinant tissue-type plasminogen activator and Lys-plasminogen to enable monitoring of the fibrinolysis phase following clot formation, termed the CLySis assay. This evidence concerns the gene PLAT and familial hypodysfibrinogenemia.