Hematopathology is a branch of pathology that study of hematopoietic  cells . Hematopathology may be a board certified subspecialty (American Board of Pathology) practiced by those physicians who have completed general pathology residency (anatomic, clinical, or combined) and extra fellowship training in medical specialty. Hematopoietic cells originate from the bone marrow and contribute the cellular parts of blood as well as red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (megakaryocyte-derived bodies). Leukocytes contribute considerably to the cellular composition of body fluid nodes, the spleen, the thymus, and tissue layer associated with humor tissues, and area to some extent of all the tissues discussed here. Diseases of the organic process system typically manifest as decreases (anemia) or will increase (lymphoma/leukemia) in these cell varieties. Consequently, hematopathologists most often measure peripheral blood smears, bone marrow aspirates and biopsies, and body fluid nodes biopsies to work out the character of organic process illness. The hematopathologists incorporates earliest research with subsidiary techniques as well as general laboratory values, , flow cytometry, and molecular diagnostic tests to determine the exact diagnosis. The hematopathologist works closely with the hematologist/oncologist specialty doctor who sees the patient and decides on the simplest treatment primarily based upon the designation created by the hematopathologist.