Blood is composed of particles, proteins, and fluids that are made in the lymphatic organs and bone marrow. Patients are normally under a hematologist’s care, via referral from a primary caregiver or hospital, if their symptoms or tests indicate anemia, a blood clotting disease, blood count irregularities, or platelet irregularities. To diagnose diseases, hematologists perform intense analysis of the blood, blood cells, and bone marrow cells.

Hematology is often combined with other disciplines to diagnose and treat diseases where blood is involved.  Hematopathologists are doctors who specialize in diseases of the blood but also of the organs and tissues that are fueled by blood cells, such as the lymph nodes, spleen, thymus, and lymphoid tissue, and are often experts in diagnostics where multiple symptoms are involved.

The hematology and oncology specialties overlap in cancer treatment. Hematology and oncology doctors prescribe and perform stem cell transplants, bone marrow transplants, chemotherapy, and pheresis (a procedure in which blood is filtered, separated, and a portion retained, with the remainder being returned to the individual). These therapies are used to treat lymphoma, Hodgkin’s disease, non-Hodgkin’s lymphoma, multiple myeloma, and immunity diseases. Hematologists work in laboratories, blood banks, hospitals, cancer treatment centers, and medical offices.

Hematologists rely on blood tests as a primary diagnostic tool. These tests can include, but are not limited to:

• Blood count (CBC), which helps in diagnosing anemia and certain blood cancers, as well as monitoring infection and blood loss.
• Platelet count, which is used for diagnosing diseases and monitoring bleeding and clotting diseases.
• Erythocyte sedimentation rate (ESR), which measures the rate at which red blood cells fall to help diagnose sickle cell anemia, polycythemia, and congestive heart failure.
• Prothrombin time (PT), which evaluates bleeding and clotting disease and can help monitor anti-clotting therapies.
• Bone marrow biopsies, which test for abnormal red or white blood cell counts shown in cancerous diseases, such as leukemia, Hodgkin’s disease, or anemia.
• Antiglobulin/Coombs test, which measures for antibodies that destroy red blood cells that may cause anemia, jaundice, mononucleosis, syphilis, lymph proliferative disorder, or blood transfusion reactions.
• Diascopy, a simple test to see how skin blanches under pressure to diagnose various conditions.