describe the composition of capillary blood
Venous, Arterial, and Capillary Blood Specimens. Venous Blood. Venous blood is deoxygenated blood that flows from tiny capillary blood vessels within the tissues into progressively larger veins to the right side of the heart.Venous blood is the specimen of choice for most routine laboratory tests.apillary Blood. Capillary blood is obtained from capillary beds that consist of the smallest veins (venules) and arteries (arterioles) of the circulatory system. The venules and arterioles join together in capillary beds forming a mixture of venous and arterial blood.