Phlebotomy is the removal of blood through the puncture of a vein. The history of phlebotomy has its roots in bloodletting to cure multiple ailments. Today, the removal of blood as a therapeutic intervention is limited to a few conditions, but phlebotomy is widely performed to obtain blood for laboratory tests.
The most common indication for phlebotomy is to obtain a blood sample for laboratory testing. In pediatrics, the most common therapeutic reasons for phlebotomy are to reduce the hematocrit in infants with polycythemia and to perform exchange transfusions in patients with sickle cell disease and hemolytic disease of the newborn.
There are virtually no absolute contraindications to phlebotomy. Relative contraindications are the existence of a bleeding disorder and severe anemia, but even in those circumstances, blood studies are needed for the evaluation of the patient. One should avoid drawing blood in areas where trauma or infection is a concern, and from surgically placed fistulas used for dialysis.
Table 194-1 lists the equipment needed for phlebotomy.
TABLE 194-1Equipment Needed for Phlebotomy |Favorite Table|Download (.pdf) TABLE 194-1 Equipment Needed for Phlebotomy
|Alcohol swab |
|Povidone–iodine solution (if drawing blood culture) |
|Butterfly needle (21, 23, or 25 gauge) |
|Syringe or evacuated tube adapter |
|Evacuated laboratory tubes |
|Sharps disposal container |
There are two common collection methods when phlebotomy is used to obtain samples for laboratory testing. Blood can be collected into a syringe attached to the needle or directly into evacuated laboratory tubes if the needle is attached to a plastic evacuated tube adapter. In pediatric patients, 21-, 23-, or 25-gauge butterfly winged infusion needles (also called butterfly needles) are most frequently used.
After obtaining all the equipment, one should wash one’s hands and put on gloves. Position the patient so that he or she is comfortably sitting or lying down, with the arm extended on a flat, sturdy surface. Some patients may need to be physically restrained by support staff or with a papoose; however, children often benefit from nonpharmacologic relaxation techniques or other distraction methods. The use of a child life specialist can be particularly helpful. In infants, orally administered glucose-containing solutions can reduce pain.
Tie a tourniquet on the upper arm, and inspect the antecubital fossa for a visible or palpable vein suitable for venipuncture. Repeat on the contralateral arm if needed. The dorsal surface of the hands is another location to search for veins (Figure 194-1). In infants, it may be difficult to visualize or palpate veins, and one can consider using the lower extremities or scalp veins to obtain blood samples.
Common sites for venipuncture. (Adapted from Williams PL. Gray’s Anatomy: ...