Snapshot: This document provides an overview of phlebotomy, along with key steps and clinical considerations. Also included is a brief library of video links that demonstrates how to perform this skill.
Instructional Videos for Phlebotomy
What is Phlebotomy?
- Phlebotomy is the practice of drawing blood from a vein. Blood samples are then sent to a laboratory to provide a wide variety of clinical information, including electrolytes, blood gases and clotting times, to name a few.
- A person who performs phlebotomy is termed a ‘phlebotomist.’ Phlebotomists may be RN’s, physicians, trained patient care technicians (“techs”), or other healthcare workers. While technicians may draw blood, interpreting and acting upon data from blood specimens is only within the scope of practice of an RN, or an MD.
- Obtaining blood specimens is a critical nursing skill. Phlebotomy is vital for a variety of medical diagnoses, tests and procedures. Poor or untimely specimens can lead to unhelpful or even harmful medical treatment.
General Phlebotomy Tips
- Practicing phlebotomy is the way to build skills and confidence. While phlebotomy requires knowledge of basic anatomy, and a clear understanding of the potential risks and complications patients can face, it is a “hands on” art. As is true for many clinical skills, a task that initially seems difficult can become second nature with time and practice.
- Find a place and time to practice. If you’re nervous practicing phlebotomy where you work (or don’t have many opportunities to practice), ask if you can shadow someone in a clinical area where phlebotomy is frequently performed, such as in surgical areas or an emergency room. Ask around to find an experienced nurse or mentor who can teach you; many experienced nurses are happy to teach others if their time and efforts are appreciated.
- Go by feel. While the steps and advice below should serve as a general guide, ultimately you’ll find your own approach to this skill. Experienced phlebotomists can often look at a patient and instinctively find the right location from which to draw blood. The key to phlebotomy is not only following the right steps, but in finding the right place to draw blood, especially for individuals who are “hard sticks,” such as the elderly, diabetics, dialysis patients, and individuals who have undergone chemotherapy.
Appropriate & Inappropriate Sites for Phlebotomy
- The first choice site for most patients is the median cubital vein in the antecubital fossa. This vein is sometimes commonly referred to “the antecubital” or “the AC.” This vein typically forms an “H” in the ‘pit’ of the elbow between the median cephalic and median basilic veins; in other individuals, it may assume an “M” formation between the median cephalic and median basilic veins in the ‘pit’ of the elbow.
- This vein is usually the first choice because it is close to the skin’s surface, is relatively immobile (it tends not to roll when punctured), carries a low risk for damaging surrounding nerves, arteries and tendons (which are not immediately nearby), and is less painful to puncture compared with other veins.
- The second choice in most patients is the cephalic vein. This vein is located on the lateral (“outer”) side of the upper arm (that is, the outer edge of the upper arm and forearm when the arm extended with the palm facing up); it connects with the basilic vein via the median cubital vein in the antecubital fossa.
- For most patients, this vein is also relatively close to the skin’s surface, relatively immobile, and has few nearby nerves, arteries and tendons that could be accidentally punctured
- Unless you are unable to access the median cubital or cephalic veins, avoid drawing blood from the basilic vein. This is the vein on the medial (“inside”) side of the upper arm and forearm, which connects to the cephalic vein via the median cubital vein in the antecubital fossa
- For most patients, this vein is close to the brachial artery and median nerve, and is more prone to role and form hematomas compared with the median cubital and cephalic veins.
- You should also avoid drawing blood from the following sites:
- Edematous sites (i.e. swollen sites filled with serous fluid)
- Scarred or burned areas
- Fistulas and grafts
- From an IV cannula (unless permitted by your institution)
- Sites above an IV cannula. (Note: if you have to go above an IV cannula, turn IV off for 5 – 10 mins and draw a waste tube before drawing your blood sample).
- Arm with PICC line (peripherally inserted central catheter)
- Arm on side of a mastectomy
- Arm in which blood is being transfused
- If a patient has poor IV access and requires multiple blood draws, consider a central line. Nurses are in a position to advocate for patients who are ‘hard sticks.’ While putting in a PICC or other central line is somewhat initially complex, it can make drawing blood much easier and more convenient, for nurse and patient alike.
Steps for Phlebotomy
- Gather the materials you need in advance. Your supplies should include a tourniquet, 2 inch x 2 inch gauze pads, paper tape, gloves, alcohol wipes, a blood specimen bag (to send the samples to the lab when you’re finished), and blood specimen tubes (aka ‘vacutainers’).
- Note: especially when you’re still learning, it’s helpful to take extra blood specimen tubes so that, if you are initially unsuccessful and need to pierce more than one tube to draw your sample, you have extras on hand. Keep in mind that once a tube is punctured its vacuum usually dissipates, which makes it more difficult to drawn blood from the vein that you puncture.
- Select the appropriate needle. The type of needle you select to draw blood depends upon your patient and your institutional guidelines. Many nurses favor so-called “butterfly needles,” which are helpful for drawing blood from smaller and harder-to-access veins; the downside is such needles tend to be more costly. If you will be drawing blood from the antecubital vein on a patient who isn’t an especially “hard stick” (i.e. difficult to draw blood from), you could use a so-called vacuum extraction system, which uses a large needle that goes straight into the vein.
- Perform positive patient identification. Before you draw blood, it is critical to ask your patient to state his or her name and date of birth, and then use their armband to confirm their identity. This is a basic and important step that some nurses overlook. The last thing you want to do is draw blood for the wrong patient, or mislabel a tube, which can cause serious medical errors.
- Follow universal precautions. Again, this is a basic step that some nurses overlook. Before you begin, perform proper hand hygiene; vigorously wash your hands for at least 20 seconds in warm, soapy water, scrubbing between fingers and scrubbing nail beds too. Then, put on gloves, and follow any other precautions necessary for your patient (e.g. if the patient is on contact isolation, put on a hospital gown as well).
- Locate a good candidate site and assess the arm for contraindications. You should select a vein that is palpable, visible, and straight. The vein should feel spongy, not hard, to the touch, and should not “roll” too much. To perform an accurate assessment, you should have adequate lighting in the room. Finally, be sure to avoid contraindicated sites for phlebotomy (see the section “Inappropriate Sites.”)
- Listen to patients when selecting a vein. Patients, especially those who frequently have blood drawn, know their own bodies better than you do. If a patient tells you that a particular site isn’t a good place to draw blood, pay attention and try to select a different location.
- Help the patient into the proper position, and apply the tourniquet. To draw blood, ask the patient to extend their arm while lying in bed, or while sitting comfortably in a chair. Apply the tourniquet 3 – 4 inches above the insertion site, and only when you’re ready; you shouldn’t leave the tourniquet in place for more than about one minute. (If you need longer to find a site, release tourniquet for at least 2 minutes, then reapply it). Once the tourniquet is on, place the patient’s arm in a dependent position, and ask him or her to close their first once or twice. The patient doesn’t need to “pump” his or her fist open and closed, and you should avoid the use of heating pads, which can cause burns.
- Sterilize the site. Once you selected an appropriate location, swab the site with alcohol; this is not only hygienic, but can also help you to better visualize the vein. Allow the alcohol to dry (wait about 10 – 20 seconds) before you insert the needle.
- Anchor the vein, and prepare your patient. Before inserting the needle, stabilize the vein by using the fingers of your non-dominant hand above and below the vein to “anchor” it in place to prevent rolling. Then, prepare your patient by saying something like, “I’m going to draw blood now.” The point is to ensure your patient is not surprised when you insert the needle, as this could lead them to jerk their arm away, injuring you or themselves in the process.
- Insert the needle, and reposition as needed. The proper way to do this is to swiftly enter the vein at a 15 – 30 degree angle, bevel side of the needle up. Once you’re in the vein, you can gently reposition the needle if you do not see any blood return in the tubing. If you’re not getting any blood return but you think you’re in the vein, you may have hit a valve, in which case you should gently pull back with the needle. While it’s alright to gently reposition the needle, you don’t want to “dig around” in the vein, which could puncture the vein and cause the patient pain.
- Fill the tube, and then release the tourniquet before you remove the needle. The vacuum in the blood specimen tube should help draw blood up into the tube; for most blood specimens the tube will be filled when it is about two thirds full. The reason to release the tourniquet before you remove the needle is to ensure you don’t forget to remove the tourniquet.
- Remove the needle and engage the safety device. You should remove the needle swiftly at about the same 15 – 30 degree angle that you inserted it. As soon as the needle is out, engage the safety device to prevent a needle-stick injury. Never re-cap a needle. Then, hold pressure on the patient’s skin with 2 inch by 2 inch gauze.
- Assess the patient for signs of bleeding/intolerance. After you’ve gotten your blood, it’s important to assess the patient’s skin. Patients who have been on blood thinners such as Heparin or Coumadin may bleed quite a bit, and require extra gauze. You want to be sure the patient has adequate circulation above and below the needle insertion site, and is not in pain once you are finished.
- Follow procedures for preparing specimens. Once you’ve obtained your blood samples, gently invert each tube a few times; don’t vigorously shake the tubes unless specifically indicated, as this can cause hemolysis, or ‘splitting’ of the red blood cells, which skews many lab results. If you are drawing multiple specimens and your lab has a policy about the order in which blood draws should occur, follow that policy. Some specimens may need to be sent on ice (i.e. blood gases, lactate, ammonia, ionized calcium, etc). If you have a question, just call your lab to find out your institution’s policy.
- Label tubing correctly. This may seem like a minor point, but it can mean the difference between getting your carefully collected specimens processed, or not. Some labs may require you to time and date the specimen; if so, be sure to do so. When applying a label to a specimen tube, ensure that the label does not extend over the cap of the tube or past the bottom of the tube. If your label has a barcode on it, the barcode should be completely visible so that it can be easily scanned for identification.
- If you’re unsuccessful obtaining blood, get help. While you should follow your institution’s policies, generally if you aren’t successful in 2 – 3 tries, stop and let someone else attempt obtaining the blood specimen. And of course, if more than one person is obtaining blood from a patient change needles between attempts; never re-insert the same needle in a patient after it has already been used.