What is a phlebotomy?
Phlebotomy is performed to acquire blood samples for microbiology, cytology, fluid analysis, or other testing. Blood collection tubes are drawn in a specific order to avoid cross-contamination of additives in tubes designed for specific tests. Collection tubes are color-coded according to the additives (if any) contained within them. An essential component of the procedure is the accurate labeling of tubes with information identifying the patient. Blood collection should be carried out only by a licensed phlebotomist.
A temporary tourniquet is applied to the arm three to four inches above the selected puncture site, the skin is cleaned with an alcohol or iodine wipe, and then a needle is inserted into a vein (venipuncture). Blood can also be collected from an artery or fingerstick, if appropriate. Often, the skin is palpated and the vein is traced with a finger, or the arm may be massaged until a superficial vein is readily apparent. After one or more tubes of blood (typically about ten milliliters in volume) are collected, a gauze sponge is applied until bleeding stops and then an adhesive bandage is applied. The tourniquet is immediately removed after the last tube to be drawn starts to fill. The entire procedure takes only a few minutes.
When smaller volumes of blood are required, collection can be accomplished by a simple fingerstick on the third or fourth finger of the nondominant hand, using a sterile lancet. The first drop of blood is wiped away, and then blood is collected into a capillary tube while the finger is gently massaged. After the fingerstick procedure, the patient normally is instructed to hold a small gauze pad over the puncture site for a few minutes to stop the bleeding. For blood collection on a newborn baby or infant, the heel is the recommended puncture site.
Phlebotomy is a routine procedure with minimal risks. Trained phlebotomists take precautions to protect themselves and the patient from exposure to blood-borne diseases and to prevent the occurrence of infection. These precautions include the use of rubber or latex gloves and only new, sterile disposable tubes and needles. Most frequently, blood is taken from the larger and fuller median cubital and cephalic veins of the arm; wrist and hand veins can also be acceptable. Certain areas are avoided in venipuncture: extensive scar tissue from burns or injury, the site of a previous mastectomy, regions of hematoma, sites of intravenous (IV) therapy and blood transfusion, cannula or fistula devices, and extremities suffering from edema. Some patients may experience light-headedness or even faint during blood collection; to prevent accidents, the patient remains seated during the brief procedure.
Garza, Diana, and Kathleen Becan-McBride. Phlebotomy Handbook: Blood Collection Essentials. 7th ed. Upper Saddle River, N.J.: Pearson/Prentice Hall, 2005.
Hoeltke, Lynn B. The Complete Textbook of Phlebotomy. 4th ed. Albany, N.Y.: Delmar, 2012.
McCall, Ruth E., and Cathee M. Tankersley. Phlebotomy Essentials. 5th ed. Baltimore: Wolters Kluwer/Lippincott Williams & Wilkins, 2012.
"Venipuncture." MedlinePlus, August 31, 2011.