There are many conditions of or affecting the human hematologic system — the biological system that includes plasma, platelets, leukocytes, and erythrocytes, the major components of blood and the bone marrow.
An anemia is a decrease in number of red blood cells (RBCs) or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin deficiency.
Anemia is the most common disorder of the blood. There are several kinds of anemia, produced by a variety of underlying causes. Anemia can be classified in a variety of ways, based on the morphology of RBCs, underlying etiologic mechanisms, and discernible clinical spectra, to mention a few. The three main classes of anemia include excessive blood loss (acutely such as a hemorrhage or chronically through low-volume loss), excessive blood cell destruction (hemolysis) or deficient red blood cell production (ineffective hematopoiesis). Based on 2005-2006 estimates, the Centers for Disease Control and Prevention has stated that approximately 5.5 million Americans a year are either admitted to a hospital or seen by a physician, with some form of anemia as their primary diagnosis.
A nutritional anemia is a type of anemia that can be directly attributed to either a nutritional disorder or a nutritional deficiency.
A blood cancer or hematological malignancy is a type of malignant cancer that originates, affects, or involves the blood, bone marrow, or lymph nodes. These cancers include leukemias, lymphomas, and myelomas. These particular types of cancers can arise as defected mature cell types that have differentiated from hematopoietic precursor cells (often in the bone marrow) and begin to quickly proliferate through the bloodstream where it can then often infiltrate other organs and tissues. Others can involve the formation of tumors from lymphoblasts from within the lymphoid tissue. Incidence of affected people with a form of blood cancer has been steady increasing over recent years; however, due in part to early detection methods and subsequent advancements in the treatment of the diseases, mortality rates have continued to decrease.