Hematological disorders describe different kinds of pathological conditions that primarily affect the blood or blood-forming organs, e.g. red blood cells, white blood cells,

platelets, blood vessels, bone marrow, lymph nodes and spleen, as well proteins that are involved in bleeding and clotting processes. 

Common blood disorders - besides blood cancers - include conditions leading to primary immunodeficiencies, blood volume loss, bleeding disorders (blood clots) and rare diseases such as anemia (haemophilia A and B), sickle cell disease, etc. Blood disorders are critical, since they can affect the overall health of a person.

Source: nature.com; American Society of Hematology; National Institute of Diabetes and Digestive and Kidney Diseases; Rare Disease Report