Phlebotomy—the practice of taking samples of patients’ blood and other body tissue for medical testing, research or blood-banking—is usually performed by a trained phlebotomist or a lab professional. The most common procedures performed by phlebotomists are venipuncture, in which a sample of blood is taken from a vein (customarily in the arm), and a fingerstick, which takes a smaller blood sample from a fingertip. While most venipuncture and fingerstick procedures are simple and incident-free, complications may arise due to either the patient’s health or a phlebotomist not following the correct draw procedure.
A hematoma is a collection of blood that pools in the tissue around a vein. It may look like a bruise or be raised, and it is often painful. Hematomas are usually caused when a phlebotomist “misses” a vein, only partially enters a vein or punctures a vein completely during a routine venipuncture. Most hematomas are merely uncomfortable; however, special care should be paid to children, the elderly and patients who have bleeding disorders or are taking blood-thinner medication.
To prevent a hematoma, the phlebotomist should: choose a surface vein to puncture; ensure that he or she enters the vein at a correct angle; and avoid probing the vein with the needle.
Treatment of a hematoma includes raising the patient's affected area higher than the heart, while applying ice and gentle pressure to the area.
Prolonged Tourniquet Application
A tourniquet is an essential tool that assists a phlebotomist in initially locating (palpating) and entering a vein. However, tourniquets should remain on a patient for no longer than two minutes; otherwise, the phlebotomist risks both the integrity of the collected blood sample (called hemoconcentration) and the health of the patient. Prolonged tourniquet application may lead to irreversible tissue or nerve damage.
If a phlebotomist has trouble locating a vein, he or she should untie the tourniquet and warm the area with a warming light or handheld warmer. The patient should make a slight fist; the tourniquet should then be retied and the area palpated again. If the phlebotomist still cannot locate a vein, he or she should remove the tourniquet and then try the other arm (or an alternate area).
If a patient has had a tourniquet applied and complains of unusual pain, numbness or tingling, a supervisor should be contacted and medical personnel called immediately.
Hemolysis is a complication that happens not to a patient, but rather to the collected blood sample. When a blood sample is collected incorrectly or handled roughly, the red blood cells in the sample can undergo “lysis,” in which the cells break apart. Hemolysis can affect or even negate the results of many tests.
Phlebotomists should handle blood collection tubes with care. If the tubes contain an additive and need to be mixed, the phlebotomist should gently invert the tubes instead of shaking them.