Hemophilia A and B predominantly attracts clinical attention in males due to X-linked inheritance, introducing a bias toward female carriers to be asymptomatic. This common misconception is contradicted by an increasing body of evidence with consistent reporting on an increased bleeding tendency in hemophilia carriers (HCs), including those with normal factor VIII/IX (FVIII/IX) levels. The term HC can hamper diagnosis, clinical care, and research. Therefore, a new nomenclature has been defined based on an open iterative process involving hemophilia experts, patients, and the International Society on Thrombosis and Haemostasis (ISTH) community. The resulting nomenclature accounts for personal bleeding history and baseline plasma FVIII/IX level. It distinguishes five clinically relevant HC categories: women/girls with mild, moderate, or severe hemophilia (FVIII/IX >0.05 and <0.40 IU/ml, 0.01–0.05 IU/ml, and <0.01 IU/ml, respectively), symptomatic and asymptomatic HC (FVIII/IX ≥0.40 IU/ml with and without a bleeding phenotype, respectively). This new nomenclature is aimed at improving diagnosis and management and applying uniform terminologies for clinical research.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease in 2019 (COVID-19) which rapidly evolved from an outbreak in Wuhan, China into a pandemic that has resulted in over millions of infections and over hundreds of thousands of mortalities worldwide. Various coagulopathies have been reported in association with COVID-19, including disseminated intravascular coagulation (DIC), sepsis-induced coagulopathy (SIC), local microthrombi, venous thromboembolism (VTE), arterial thrombotic complications, and thrombo-inflammation. There is a plethora of publications and conflicting data on hematological and hemostatic derangements in COVID-19 with some data suggesting the link to disease progress, severity and/or mortality. There is also growing evidence of potentially useful clinical biomarkers to predict COVID-19 progression and disease outcomes. Of those, a link between thrombocytopenia and COVID-19 severity or mortality was suggested. In this opinion report, we examine the published evidence of hematological and hemostatic laboratory derangements in COVID-19 and the interrelated SARS-CoV-2 induced inflammation, with a focussed discussion on platelet count alterations. We explore whether thrombocytopenia could be a potential disease biomarker and we provide recommendations for future studies in this regard.