Hematology is the medical study of blood. The word comes from the Greek word "heme," meaning "blood," and the suffix "ology," which designates an academic field of study. Hematologists study and treat blood disorders.
While hematology focuses primarily on blood conditions, hematologists frequently work with bone marrow and lymph system conditions, as well. Some diseases, such as leukemia, start in the bone marrow and affect the blood cells. Other blood conditions, such as hemophilia, involve abnormal structures in the blood.
Hematologists follow a similar education path as doctors in other specialties. They start with undergraduate schooling, followed by four years of medical school. Students then complete three years of residency, gain the appropriate licenses and continue their training with two to four years of fellowship study in hematology.