Bloodletting is the withdrawal of often considerable quantities of blood from a patient to cure or prevent illness and disease. Bloodletting was based on an ancient system of medicine in which blood and other bodily fluid were considered to be “humors” the proper balance of which maintained health. It was the most common medical practice performed by doctors from antiquity up to the late 19th century, a time span of almost 2,000 years. The practice has been abandoned for all except a few very specific conditions.
Today, the term phlebotomy refers to the drawing of blood for laboratory analysis or blood transfusion . Therapeutic phlebotomy refers to the drawing of a unit of blood in specific cases like hemochromatosis, polycythemia vera, porphyria cutanea tarda, etc., to reduce the amount of red blood cells
Hemochromatosis is a genetic disorder of iron metabolism leading to abnormal iron accumulation in liver, pancreas, heart, pituitary, joints, and skin. It is treated with periodic phlebotomy to maintain ferritin levels at a reasonable level so as to minimize further iron deposition.
Polycythemia vera is a stem cell bone marrow disorder leading to overproduction of red blood cells and variable overproduction of white blood cells and platelets. Its treatment includes phlebotomy to reduce the red blood cell mass and decrease the chance of dangerous clots.
Porphyria cutanea tarda is a group of disorders of heme metabolism with an associated abnormality in iron metabolism. Phlebotomy is also used to decrease iron levels and prevent accumulation in various organs.