What it means
Blood flowing back to the heart through the veins. Except in the pulmonary veins, it carries less oxygen and more carbon dioxide than arterial blood and is a darker red. Most lab tests are done on venous blood taken by venipunctureVEN-ih-punk-cherPutting a needle into a vein to draw blood or start an IV.ven/o veinpuncture to pierceFull entry ; a venous blood gas is sometimes used in place of an arterial one.
Related terms
arterial blood gas
A blood test from an artery that measures oxygen, carbon dioxide, bicarbonate and the blood's pH.
venipuncture
Putting a needle into a vein to draw blood or start an IV.