Hematology is the study of the blood and blood disorders in the body. A hematologist is a physician who has expertise in diseases of the blood and bone marrow, and treats vascular and clotting problems. The hematologist also treats blood disorders such as hemophilia, leukemia, lymphoma, anemia and sickle cell disease.

Physicians in this specialty treat patients suffering from numerous diseases and illnesses, but some of the most common are Malaria, lymphoma, Non-Hodgkin's Lymphoma, Myelomas, Evans' syndrome, AIDS, Leukemia, hemophilia, Thrombocytopenia, Sickle-cell disease, Myeloma, Pernicious anemia, Hodgkin's disease, Thalassemia, Myelofibrosis, Infectious mononucleosis, Agranulocytosis, Systemic lupus erythematosus (SLE), Megaloblastic anemia, and Autoimmune hemolytic anemia.

Once properly diagnosed, practitioners can perform numerous procedures on patients including Chemotherapy, Bone marrow transplant, blood transfusion, radiotherapy, Intramuscular injections, Anticoagulation therapy, and Venesection.

To diagnose patients with possible illnesses and diseases, specialists will often perform one of many tests including Coombs test, D-dimer, Prothrombin time, Bone marrow biopsy, Protein electrophoresis, serum Ferritin level, Partial thromboplastin time, Vitamin B12 and Folate levels, Erythrocyte sedimentation rate (ESR), Blood film, Full blood count, and Hemoglobin electrophoresis.

Doctor density varies by specialty and location. Illinois has 580 practicing hematologists. Broken out by city, hematology doctor density in Palos Heights is 8, in Pana is 1, in Paris is 1, in Park Ridge is 14, in Peoria is 17, in Pinckneyville is 1, in Pittsfield is 1, and in Plainfield is 2.

Most people think that Chicago, because of its size and popularity, is Illinois’ capital city, but that distinction belongs to Springfield, home of the Abraham Lincoln Museum. Illinois has hundreds of museums, numerous yearly art and ethnic festivals, a lakeshore bordering Lake Michigan, and the many national forests and parks that offers visitors camping, horseback riding, biking, kayaking, and fishing. Chicago is home to the Sears Tower, the Shedd Aquarium, the Art Institute of Chicago, the Adler Planetarium, the Museum of Science and Industry, and other cultural opportunities and restaurants in the Navy Pier area.

According to 2005 Census estimates, Illinois has a population of 12,763,371. Of this population, 3,172,677 are under the age of 18 and 1,523,937 are at or above the age of 65.