The blood is usually drawn from a vein in the forearm or the hand. First, the skin over the vein is cleaned with an antiseptic. Next, a strong rubber tube called a tourniquet is wrapped around the upper arm. This enlarges the veins in the lower arm by restricting blood flow through them. A very thin needle is gently inserted into a vein and the tourniquet is removed.
Blood flows from the vein through the needle and is collected in a syringe or vial.
The sample is sent to the lab to be analyzed. After the needle is withdrawn, the puncture site is covered for a short time to prevent bleeding. A cholesterol test is generally done after the individual has fasted overnight. By visiting this site, you agree to the terms and conditions of our Visitor Agreement .