Finger-Sticks - A small number of blood tests require just a finger-stick. A very small sample of blood from your capillaries can be obtained from the fingertip or earlobe, or from the heel or big toe of a newborn.

Warming the skin with moist compresses for about 10 minutes facilitates blood flow to the area. The skin is then pricked with a lancet. Because there are more nerves in the finger than in your elbow, you may find that a finger-stick is a bit more painful than venipuncture, although less intimidating, counsels Flaherty. A new finger-stick device is, however, winning praise from patients, reports Daly: "People say they don’t even feel it." This kind of testing is increasing, she says, especially for older patients.

Arterial Samples - In more critical situations—usually not outpatient diagnostic tests—the blood from a patient’s arteries needs to be analyzed. This procedure, known as an arterial sample, is performed by a doctor or specially trained nurse. A local anesthetic may be administered, and afterward, the nurse will apply pressure to stop the bleeding and prevent a hematoma.