Hematology is the study of diseases of the blood and bone marrow, as well as diseases of the immune, hemostatic (blood clotting), and vascular systems. The science of haematology has a significant impact on our understanding of many diseases due to the nature of blood. Hematologists are typically board-certified internists or paediatricians who have undergone additional years of haematology training. Hematologists specialise in providing direct patient care as well as identifying and treating hematopoietic diseases, including malignancies. A hematopathologist is often board-certified in both anatomical and clinical pathology, as well as having additional years of hematopathology training. Hematopathology is more than only the study of blood and bone marrow diseases. It also encompasses the study of organs and tissues that rely on blood cells to carry out their physiologic tasks. The lymph nodes, spleen, thymus, and other lymphoid tissue are among them. Hematopathologists specialise in the diagnosis of hematopoietic and lymphocyte-rich tissue diseases. This is normally done in the lab with a direct examination of tissue and blood.