American Society of Hematology disorders of the hematopoietic, hemostatic, and lymphatic systems, and disorders of the interaction between blood and the blood vessel wall. An American hematologist has trained in a subspecialty program approved by the American Board of Internal Medicine or the American Board of Pediatrics, or has acquired a comparable education in the field by alternate means, and is Board Certified (or eligible) in the subspecialty of hematology. Diagnostic expertise of a hematologist A hematologist is expert in the investigation, diagnosis, and management of disorders of the aforementioned organ systems through the use of the medical history, physical findings, specialized clinical laboratory
White blood cell used categories of white blood cell disorders divide them quantitatively into those causing excessive numbers (proliferative disorders) and those causing insufficient numbers (leukopenias). Leukocytosis is usually healthy (e.g., fighting an infection), but it also may be dysfunctionally proliferative. WBC proliferative disorders can be classed as myeloproliferative and lymphoproliferative. Some are autoimmune, but many are neoplastic. Another way to categorize disorders of white blood cells is qualitatively. There are various disorders in which the number of white blood cells is normal but the cells do not function normally. Neoplasia of WBCs can be benign but is often malignant. Of the various