Blood specimen collection is one of the most underestimated procedures in health care. Because it looks deceptively simple, nurses, clinical nursing assistants, radiologic technologists, respiratory therapists, physicians and others are all being asked to “take a stab” at phlebotomy.
Knowledge of vein selection, the order of draw, test-specific handling, storage and transportation requirements, anatomy of the antecubital area, safety precautions, alternative sites and other factors make phlebotomy a highly technical procedure that takes months to learn and apply.
Like any other procedure, there are certain established and indisputable rules collectors should apply in order to consistently perform venipunctures cleanly, safely, successfully and with little or no discomfort to the patient. Some of these rules are so fundamental they could be collectively referred to as the commandments of phlebotomy. Since 10 is a popular number for commandments, let’s comply with tradition even though the list is admittedly much longer.1 Thou shalt protect thyself from injury. Today, drawing a sample of blood can potentially expose the health care worker to at least 20 communicable diseases.1 Most of them are life threatening, some of them cause incurable and fatal disease, but all of them may be preventable if health care workers use appropriate caution, technique and equipment.
It has been estimated that 1 million health care workers sustain accidental needlesticks every year.2,3 Thousands of these workers will contract some form of hepatitis; 50-60 of them will become seropositive for HIV.4 Hollow-bore needles, the kind used for collecting blood, account for 68.5 percent of all accidental needlesticks,3 and the use of winged infusion (“butterfly”) sets account for 35 percent of accidental needlesticks.5 Even more alarming is that up to 92 percent of accidental needlestick injuries suffered by laboratory personnel go unreported.3 Avoiding the use of winged infusion sets and using gloves, needle disposal units and proper technique can significantly minimize the risk of injury.2 Thou shalt identify thy patients. This means referring to an identifying bracelet affixed to the patient or asking the patient to state his or her name. Because sedated or semi-conscious patients can respond affirmatively to any question, go beyond seeking an affirmation of their identity and request they state their name in full.
In the case of an emergency room patient whose full identity has not been established, a temporary identifier such as an assigned number is acceptable but should be amended when complete information is available. When positive identification is not possible by either of these methods, have the patient’s nurse or other caregiver identify the patient and document the name of the person who verified the patient’s identity for you. No other methods are acceptable.3 Thou shalt puncture the skin at about a 15 degree angle. Most textbooks agree that a 15-30 degree angle of insertion is optimal.6 This low angle of entry allows for a greater margin of error in judging the depth of penetration and greatly reduces the risk of passing through the vein and provoking underlying structures such as nerves, tendons and arteries. This is not to say that we all must start carrying around protractors to measure our angles, but inserting the needle at as low an angle as possible minimizes the risk to the patient and facilitates a successful puncture.
As an expert witness in cases involving injury to patients during venipuncture procedures, a majority of the nerve injuries I see involve an excessive angle of insertion. Injure a patient while puncturing at a steep angle and you will have a difficult time convincing the jury that you are immune from the standards as set forth in the literature.4 Thou shalt glorify the medial vein. Of the three veins in the antecubital area acceptable for venipuncture, the median cubital vein (in the middle) is the vein of choice for four reasons: 1) it’s more stationary; 2) puncturing it is less painful to the patient; 3) it’s usually closer to the surface of the skin; and 4) it isn’t nestled among nerves or arteries.
When conducting your survey of the antecubital area, check both arms for the medial vein before considering one of the alternatives. If one is not prominent enough to instill confidence, default to the cephalic vein on the lateral or thumb side of the arm as a second choice. Keep the basilic vein (located on the medial or inside aspect of the antecubital area) as a last resort. The proximity of underlying nerves and the brachial artery make punctures in the area of this vein highly risky. Most permanent nerve injuries and arterial nicks I see result from misguided punctures into this vein. That is not to say the basilic vein should not be punctured. In many cases it is the prominent vein in the antecubital area.
However, when it is not visible and/or the initial puncture is unsuccessful, probing the area subjects the patient to the potential for excruciating pain and permanent injury more so than probing in the area of the cephalic or medial veins.5 Thou shalt invert tubes containing anticoagulants immediately after collection. A high percentage of specimens rejected by laboratories are due to clots in lavender- or blue-stoppered tubes. A quick inversion after collection prevents a second puncture. If not inverted immediately upon filling, invert the tubes as soon as possible after the puncture.
Drawing blood from a syringe requires extra consideration to prevent clotting. The moment blood enters the barrel of the syringe the clotting process begins. If the time it takes to fill the syringe and evacuate the specimen into the tubes exceeds 1 minute, significant clotting may take place. Not only will this make it difficult to evacuate the specimen through the needle and into the tubes, but if the clots are small enough to go undetected they can affect the accuracy of the results.6 Thou shalt attempt to collect specimens only from an acceptable site. Antecubital and hand veins are acceptable sites unless their use is precluded by intravenous infusions, injury or mastectomy. Any other site should be approached with great trepidation.
The anterior, or palm side, of the forearm is particularly susceptible to injury because of the close proximity of nerves and tendons to the surface of the skin and should not be considered.
Foot and ankle veins can be acceptable sites for venipunctures in some facilities and on some patients. However, puncturing these veins can lead to thrombophlebitis and clot formation in patients with coagulopathies or to tissue necrosis in diabetics. Therefore, before puncturing foot and ankle veins, make sure the facility does not have a policy against such punctures and that the physician approves of the site.7 Thou shalt label specimens at the bedside. There is no excuse for not completely labeling a specimen at the bedside. This means complete identification, not just temporary identifiers to remind you when you find time to label them completely later.
Patients have died as a result of mislabeled specimens. Case in point: At a small Midwestern hospital, a lab tech drew a specimen of blood to determine the blood type of a patient. She left the room without properly labeling the specimen, drew two more patients, then returned to the lab to type them all simultaneously. After an interruption, she returned to her workstation, misidentified the specimens and typed the patient incorrectly. The patient received incompatible blood and subsequently died.
Although this concept of complete and accurate specimen identification has been trumpeted loudly and clearly for decades, delayed labeling practices persist. On one ward at a large hospital, collectors scrawled patients’ last names on the caps of the tubes to facilitate complete labeling at a later time. The bottom line is without exception: label the specimen completely at the bedside.8 Thou shalt stretch the skin at the puncture site. Pulling down on the skin from below the intended puncture site with the thumb of your free hand anchors the vein and stretches the skin through which the needle will pass. Anchoring the vein is particularly important when drawing from the cephalic or basilic veins. Stretching the skin is the single most effective way to minimize the pain of the puncture.
Routinely employing this technique has two potential bonuses: your rate of successful punctures goes up and your patients thank you for considering their suffering.9 Thou shalt know when to quit. Not everyone can draw blood from every patient. Even those who elevate phlebotomy to an art form can have difficulty from time to time. This is because there are veins intentionally placed in the antecubitals of the population at random for the sole purpose of keeping skillful collectors from becoming legends in their own minds. After two failed attempts, one should seriously consider sending in someone else. That’s professionalism. It also may be the answer to your patient’s prayers. 10 Thou shalt treat all patients as if they are family. In a hospital, the only peace many patients experience is that which health care professionals bring them by their kind words, gentle technique and their smiles. Regardless of how you think your life led you to hold a position as a health care professional, consider yourself assigned by a higher authority because of the comfort you can offer to the sick and injured in your own unique and compassionate way. You haven’t been employed; you’ve been ordained.
Readers may purchase the author’s “Ten Commandments of Phlebotmy” poster through the Center for Phlebotomy Education. The 16×20 four-color graphic can be viewed and ordered at http://www.phlebotomy.com/poster.htm
Phlebotomy-Related Web Sites
- Center for Phlebotomy Education
- Q-Probes: Phlebotomy
- Welcome to the Needle Phobia Page
- Evaluation of Safety Devices for Preventing Percutaneous Injuries Among Health Care Workers During Phlebotomy Procedures
- Jagger, J. (1998). Rates of needlestick injury caused by various devices in a university hospital. N Engl J Med, 319(5), 284-288.
- Carlsen, W., & Holding, R. (1998, April 13). Epidemic rages caregivers: thousands die from diseases contracted through needle sticks. San Francisco Chronicle.
- Pallatroni, L. (1998). Needlesticks: Who pays the price when costs are cut on safety? MLO, 30(7), 30-31, 34-36, 88.
- Carlsen, W., & Holding, R. (1998, April 14). High profits–at what cost? San Francisco Chronicle.
- Jagger, J. Risky procedure, risky devices, risky job. Advances in Exposure Prevention, 1(1).
- Garza, D., & Becan-McBride, K. (1999). Phlebotomy handbook: Blood collection essentials. Norwalk, CT: Appleton & Lange.