A When performing a heel stick on an infant (<1 year of age), site selection on the heel is imperative to avoid injury. According to CLSI, "In infants less than one year old, punctures to the lateral or medial plantar surface of the heel are generally performed.... If an infant's heel is to be punctured, the site shall be on the plantar surface medial to a line drawn posteriorly from the middle of the great toe to the heel, or lateral to a line drawn posteriorly from between the fourth and fifth toes to the heel. In almost all infants, the heel bone is not under these areas. The puncture shall not be through a previous puncture site which may be infected, nor shall it be at the curvature of the heel." (1) These sites are selected to stay away from heel bones that could be injured.
This guideline, along with CLSI_Blood Collection on Filter Paper for Newborn Screening Program (2) both hold a wealth of information and standards for heel sticks on infants.
Proper blood-draw volume on infants is usually determined at the institutional level using a weight-based equation to ensure that iatrogenic anemia does not occur. I would recommend contacting the Center for Phlebotomy Education3 for literature and guidelines for determining infant blood-draw volume at your institution.
Warming the heel is necessary and recommended for site preparation to increase blood flow to the heel. Using a commercial heel warmer is completely acceptable. Just ensure that temperatures do not exceed 42[degrees]C. Refer to the CLSI guidelines for further information and suggestions.
Phlebotomy and POCT Manager
Oregon Health and Science University
1. Clinical and Laboratory Standards Institute. Procedures and Devices for the Collection of Diagnostic Capillary Blood Specimens; Approved Standard--Fifth Edition. Wayne, PA: Clinical and Laboratory Standards Institute; 2004. CLSI document H4-H5.
2. Clinical and Laboratory Standards Institute. Blood Collection on Filter Paper for Newborn Screening Programs Approved Standard--Fourth Edition. Wayne, PA: Clinical and Laboratory Standards Institute; 2003. CLSI document LA4-A4.
3. Center for Phlebotomy Education. http://www.phlebotomy.com. Accessed January 30, 2008.