Hematopathology is the branch of pathology which studies diseases of hematopoietic cells. Diseases of the hematopoietic system generally manifest as decreases (anemia) or increases (lymphoma/leukemia) in these cell types. Consequently, hematopathologists most frequently evaluate peripheral blood smears, bone marrow aspirates and biopsies, and lymph nodes biopsies to determine the nature of hematopoietic disease. The hematopathologist incorporates traditional microscopy with ancillary techniques including general laboratory values, immunohistochemistry, flow cytometry, and molecular diagnostic tests to make the most accurate diagnosis.