An operation where a vein is cut so that blood can be removed, e.g. when taking blood from a donor.
Venesection, or blood-letting, may be employed for two purposes. Most commonly, small quantities of blood may be required for analysis, as an aid to diagnosis or control of various diseases. For example, knowledge of the plasma glucose concentration is important in the diagnosis and management of diabetes mellitus, or blood may be required in order to test for infections such as HIV or hepatitis. Blood may be obtained by pricking a fingertip, or inserting a needle into a vein, depending on the amount required. Controlled bleeding of larger amounts is used in the treatment of polycythaemia.
Surgical opening of a vein for withdrawal of blood.
The act of extracting blood from a vein, whether for blood donation or therapeutic bloodletting, is known as venesection. This procedure is regularly employed to address conditions such as polycythemia, characterized by excessively thick blood, and hemochromatosis, a disorder involving the body’s iron balance.