How to tie a tourniquet for blood work

Updated November 21, 2016

A tourniquet used for venepuncture restricts blood flow. The tourniquet causes a vein to swell, which makes the vein easily accessible for blood drawing. It's important when using a tourniquet to not leave the band on for more than one minute.The tourniquet can become painful to your patient, as well as lead to hemoconcentration. As indicated by Phlebotomy, hemoconcentration is the decrease of plasma, which results in an increase of red blood cells. Hemoconcentration can cause inaccuracies in blood work.

Wash you hands before applying the tourniquet. Put on a pair of medical gloves.

Ask your patient to sit with her arms in a flat position. Look at both arms on your patient to determine which arm will have the best veins. One arm may provide more accessible veins than the other.

Tie the tourniquet 3 to 4 inches above the intended stick site (above the elbow) after locating a good vein. Ask your patient to make a fist. Don't allow him to pump his hand.

Observe your patient's skin for an enlarged blue vein. Touch the vein to ensure that the vein springs back like a rubber band. If the vein doesn't spring, locate another vein for use. Once you locate an acceptable puncture site, you are ready to draw blood.


If you can't assess a vein for venepuncture and it takes more than one minute to find a vein, release your tourniquet and try again. If you can't access a vein in two attempts, ask for another phlebotomist to access the patient's vein and draw the blood.


Don't use a latex tourniquet if your patient tells you he's allergic to latex. Latex allergies can be serious. Don't tie a tourniquet to the point of pinching the patient's skin. This can damage your patient's nerves. If you have a patient who faints during your procedure, immediately remove the tourniquet and use ammonium salts to revive your patient. Don't apply a tourniquet where there's visible scarring of the skin.

Things You'll Need

  • Disposable tourniquet
  • Gloves
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