Obtaining Blood Via Heel Stick
Iowa Neonatology Fellows
Peer Review Status: Internally Peer Reviewed
Adequate quantities of serum may be obtained via heel stick in almost any neonate. If done properly, hemolysis should not be a significant problem. The skin's blood supply is located at the junction of the dermis and subcutaneous tissue, 0.35 to 1.6 mm from the skin surface.
Prewarming with the commercially-available heel warmers or with a diaper which has been warmed under a warm faucet and taped around the heel often increases the blood supply and arterializes the sample. The area should be cleaned thoroughly with alcohol swab. The person performing the procedure should wear appropriately fitting gloves.
The heel puncture should be done on the most medial or lateral portions of the plantar surface of the heel, not on the posterior curvature, to avoid the calcaneous. The lancets are designed to enter no deeper than 2-3 mm. If using a scalpel blade, the blade should enter the skin no more than 2-3 mm. After the puncture, wipe the first small drop off to rid the skin of the tissue juices that may increase clotting at the site.
Hold the ankle area with the 3 fingers on your ulnar side while placing your thumb behind the heel and your second finger just below the ventral surface of the toes. By alternately pressing the lateral three fingers , followed by a milking motion of the second finger, blood can be expressed. The fingers should be relaxed for a few seconds periodically to allow refilling. To prevent bruising, caution should be used to limit squeezing with the finger tips. To prevent hemolysis, allow large droplets to form, collecting the drops as they form into the microtube, not scraping the blood into the tube.
Fingerstick sampling is used for capillary blood gas analysis in our NICU and may be used for additional laboratories as well. The technique is similar to heelstick in that only the medial and lateral aspects of the finger are stuck. The milking motion includes the whole finger and even portions of the hand.
Blumenfeld, et al: Recommended site and depth of newborn heel skin punctures base on anatomical measurements and histopathology. Lancet 1979;1:230.