Key Points Several regulatory mechanisms have evolved to limit the extent of clot formation after coagulation is triggered. Under normal conditions, these allow hemostasis to be achieved while preventing the growth of a hemostatic plug into an intravascular thrombus. Among…
Key Points Platelets are highly complex cells that participate in critical steps central to hemostasis and thrombosis, including adhesion to subendothelium, aggregation, secretion of granule contents, and provision of membrane surface for activation of coagulation factors. Abnormalities of either platelet…
Key Points Physiologic hemostasis consists of endothelium, platelets, plasma coagulation proteins, natural anticoagulants, and the fibrinolytic system. Primary hemostasis involves platelets and von Willebrand factor. Secondary hemostasis is initiated by the tissue factor pathway and then amplified and propagated by…
Key Points A wide range of allogeneic tissues are used for transplantation. Allograft tissue is screened, tested, and processed to improve its safety. Allograft tissue is stored by a variety of methods, including cryopreservation. Risks and complications are associated with…
Key Points Hemapheresis is the process of removing normal or abnormal components from circulating blood. Cytapheresis involves the removal of cellular components; plasmapheresis involves the removal of plasma, the liquid component. Separation of the blood components is based on size…
Key Points Blood group antigens play a variety of physiologic roles as membrane structures involved in maintaining erythrocyte cytoskeleton integrity, as well as in membrane transport, cell signaling, and immune complement regulation, and as receptors/modulators of disease. The ABO histo-blood…
Key Points Flow cytometry is a powerful, rapid, and cost-effective technique for the identification and monitoring of hematopoietic neoplasms. Successful implementation of flow cytometry requires careful attention to details of instrument and reagent performance. Normal hematopoietic cells are characterized by…
Key Points Leukocytes are regulated by complex homeostatic mechanisms that direct their responses to infection and inflammation. Leukocytosis often reflects an underlying abnormality; leukopenia, especially neutropenia, places a patient at risk for infection. Hematopoietic neoplasms have been categorized by a…
Key Points Anemia may result from decreased marrow production or shortened red cell survival. Nonmarrow diseases, such as endocrine, renal, and inflammatory disorders, significantly influence bone marrow function. Anemias associated with nutritional deficiencies may affect tissues other than the bone…
Key Points Hematopoietic stem cells are a rare population of cells in the adult bone marrow that sustains hematopoiesis and gives rise to all kinds of blood cells, including granulocytes, monocytes, lymphocytes, megakaryocytes, and erythrocytes. Differentiation and maturation of hematopoietic…