Hematology, also spelled haematology, is the branch of internal medicine, physiology, pathology, clinical laboratory work, and pediatrics that is concerned with the study of blood, the blood-forming organs, and blood diseases. Hematology includes the study of etiology, diagnosis, treatment, prognosis, and prevention of blood diseases. The laboratology work that goes into the study of blood is frequently performed by a medical technologist. Hematologists physicians also very frequently do further study in oncology - the medical treatment of cancer.