The Blood Draw
How well do you know your phlebotomist?
For some of us, that phrase plus a needlestick may be the extent of our conversation with the phlebotomist who draws our blood. We grit our teeth, look away and hope the procedure is fast and the lab results favorable.
But those results don’t just depend on the lab. They can also depend heavily on the phlebotomist’s skill at collecting that blood from our arms. So it’s worth getting to know your phlebotomist a little better—and learning a bit about what makes a good blood draw.
The term phlebotomist comes from the word ‘phlebotomy,’ which is the act or practice of opening a vein by incision or puncture to remove blood. Not long ago, collecting blood was the task of overworked nurses, medical technologists and trainee doctors, all of whom fit it in among their other duties. That all changed when phlebotomy became its own profession. One of the pioneers of that change was Kathleen Becan-McBride, EdD, MASCP, MLS (ASCP)CM at The University of Texas Health Science Center at Houston (UTHealth).
Educated as a medical laboratory scientist and educational administrator, Becan-McBride was teaching medical technology students at UTHealth in the early ‘80s when she learned that hospitals faced a shortage of people who could draw blood. At the same time, an oil bust and recession had left many Houstonians jobless. So Becan-McBride set about turning out-of-work individuals into the first generation of formally trained phlebotomists.
With the help of colleague Diana Garza, EdD, MLS (ASCP)CM, Becan-McBride created a program in phlebotomy; in the process, the two of them literally wrote the book on the subject. It wasn’t long before she and Garza were asked to design a phlebotomy curriculum for the American Society for Clinical Laboratory Sciences. It has served as a prototype for many programs all over the United States. The subject matter has evolved with the times: Becan-McBride and Garza’s Phlebotomy Handbook began with a 130-page first edition, but is now well over 600 pages in its eighth.
Today, prospective phlebotomists must hold a high school diploma or GED. A course lasts up to six months and includes both classroom and clinical time; students who complete it earn a training certificate. Some students also learn phlebotomy as part of their training to become medical laboratory technicians or scientists (MLTs or MLSs). By testing with institutions like the American Society for Clinical Pathology (ASCP), phlebotomists have the option to become board-certified.
Although she no longer personally teaches phlebotomists, Becan-McBride lectures on the topic around the world, and she is working on the ninth edition of the Handbook. She advocates for more training programs and hopes to see the day when most health care institutions hire trained and board-certified phlebotomists.
HealthLeader recently asked Becan-McBride a few questions about the art and science of collecting blood.
HealthLeader: How do you train new phlebotomists?
Dr. Kathleen Becan-McBride: First, they learn to groom themselves to be professional, to identify the patient and to know the relevant clerical duties and policies. They also need to learn good communication skills. Smiling and making eye contact is important, except with people from cultures that do not appreciate eye contact, like some Muslim women, Native Americans and Asians. Students also need to know about the zone of comfort—the area of space around the patient. Some patients move closer to the blood collector for communication since that is in their cultural background. In that case, the phlebotomist should not back away from the patient.
On the other hand, children prefer a large zone of comfort, since they do not want to have anyone close to them except for their family. The phlebotomist needs to use a calm, confident approach with kids. Again, eye contact can be reassuring. The phlebotomist should use simple commands with children and communicate during each step of the blood collection.
Teenagers are best approached as adults. Phlebotomists should explain the blood collection procedure thoroughly and ask the patient what might make them more comfortable (such as asking “Which arm?”). Maintaining privacy during the collection process is also helpful during this age.
And, of course, students have to get into anatomy and physiology—they need to know the vein structure throughout the body, as well as the anatomy of arteries and nerves. They learn about coagulation. They learn about different kinds of blood collection equipment and the proper tubes for all the laboratory tests that are out there, as well as the right order to use them in. They learn about safety for the patients, but also for themselves. When it comes time to learn to stick people, they start by practicing on dummy arms, and then they go to sticking each other.
HL: Do they also learn tricks of the trade, like slapping the veins or pumping the fist?
KBM: You actually don't want a phlebotomist to slap the veins. It makes the vein pop up, but at the same time it damages the tissue around that vein, and the tissue cells release potassium. You end up with falsely elevated potassium values. Also, other values will not be correct.
A similar thing happens if the tourniquet is left on over two to three minutes. Protein, iron and cholesterol all become falsely elevated if the tourniquet pressure is too tight or prolonged because of leakage out of the cells. Phlebotomists should put the tourniquet on for less than a minute to find that vein. While putting the equipment together to make the collection, they should take it off. Many phlebotomists forget about that.
Pumping of the fist used to be part of the protocol, but researchers have found out that pumping of the fist also can lead to falsely elevated values of potassium and some enzymes. Unfortunately, there are a lot of phlebotomists out there who aren’t aware of this. If the phlebotomist says “Pump your fist,” the patient should respond, “This can lead to falsely elevated lab values.”
HL: Tourniquets can also pinch the skin. Is it OK for the tourniquet to go on over a sleeve?
KBM: Sure; that's a great idea. Also, in the hospital, it is good to have an individual tourniquet for each patient in order to prevent a nosocomial infection (an infection that originates or occurs in a hospital or hospital-like setting).
HL: Speaking of hospitals, why do hospital patients get so many of their blood tests early in the morning?
KBM: Many of the body chemistries we measure vary throughout the day, especially things like hormones, but the body has a basal state that occurs 8 to 12 hours after the evening meal. Normal values for various tests are based upon the basal state—in other words, they build quality control on the assumption that those blood samples are collected in the morning. That’s the major reason.
HL: Many patients have to get blood tests over and over. How long does it take for a stuck vein to heal to the point where you can safely stick it again?
KBM: You don't want to go back to the same location in a vein twice for at least 2 days. It’s best to avoid building up a lot of scar tissue, because you could end up with an occlusion (blockage).
HL: Can patients become anemic from repeated blood tests?
KBM: Yes. Iatrogenic anemia (anemia caused by the health care provider) occurs frequently, especially in infants. You have so many physicians involved in a lot of these critical cases—you have one physician asking for one type of blood test, and another on the same case asking for others. We try to consolidate that in the laboratory and decrease not only the amount of blood collected but also the sticks on the patient. There is now a guide in the Phlebotomy Handbook for how much blood can safely be drawn in patients younger than 14 years old.
HL: If I’m one of those people who is a “tough stick,” is there anything I can do to make the process easier?
KBM: Drink more water. Also, let the phlebotomist know where successful blood collections have been in the past. If you have fragile veins, ask them to use a butterfly needle.
HL: Yes, many people find butterfly needles more comfortable. Are those better than a regular needle holder device?
KBM: With the regular holder, you usually use a large vacuum tube. That vacuum pulls on that vein with force to get the blood, and that can lead to hematoma (bleeding under the skin) in elderly patients. The butterfly goes with a smaller, less forceful vacuum tube. Also, with a butterfly, you can go closer to the angle of the vein.
The drawback of the butterfly needle is that it can carry a higher risk of needlestick injuries for the phlebotomist. Also, it is twice as expensive as the regular needle holder device. It costs more to dispose of, for one thing.
HL: Why is it that sometimes you feel the pain all the way up and down your arm when you are being stuck?
KBM: If the phlebotomist goes all the way through the vein and touches the nerve, that might cause that sensation. A lot of people also have an anomaly where their veins versus their nerves are located: that could allow the nerve to be touched during a blood draw. If the nerve is pierced deeply, it can be a major problem. In most cases, the needle just barely touches the nerve, and the pain will subside within a few minutes or a day or so.
HL: What happens if the phlebotomist pierces a vein through-and-through?
KBM: That does happen because people’s veins are different sizes. For one thing, the phlebotomist is not going to obtain any blood, so they will have to draw the needle back a little bit. They could also hit the nerve on the other side of the vein. Either way, the vein should heal within a few days with two punctures as well as with one. This takes two to three days for most people. But if a person is, say, elderly or a cancer patient, it’s going to take them longer.
HL: Why do some people bruise more than others after they get their blood drawn?
KBM: Bruising may be more likely to occur in people who are low in platelets or blood coagulation factors. A person with thin skin, as occurs in the elderly population, can end up with a lot of bruising. And sometimes it’s just that the phlebotomist is not the most gentle. The lower the angle the needle makes with the vein, the less trauma there is to the vein. That’s because the end of the needle has a bevel, which works more effectively when the sharp part of it is held as parallel as possible to the vein. Some phlebotomists may go in at a higher angle; then the bevel just doesn't cut as effectively. That can raise the likelihood of bruising.
HL: What else do patients need to know about getting their blood drawn?
KBM: A very important thing is to make sure that the phlebotomist is mixing the tubes of blood. For example, with a lavender-top tube, it’s extremely important to mix that 8 times for a complete blood count, otherwise you can end up with microclots that go through the laboratory instrument and alter the results. The red-top tubes have to be mixed at least 5 times. And all this is gentle mixing. Mixing too rapidly can cause hemolysis (where cells are torn open and spill their contents). So can a needle that is too small.
HL: Some phlebotomists are like magicians—the blood draw hardly hurts at all. Are they doing something differently?
KBM: Some people are just meant to be good phlebotomists. I have seen that in the students over the years—some of them just have the knack.