Final answer:
For a newborn blood specimen, the heel puncture should be done on the lateral aspects of the plantar surface to minimize pain and avoid injury.
Step-by-step explanation:
To obtain a blood specimen from a newborn, the heel is often the site of choice for the puncture. The lateral areas of the plantar surface of the heel are the recommended puncture sites to minimize the risk of injury to the infant. Care must be taken to avoid the central area of the heel as it is bony and can cause pain and injury. The medial and lateral aspects of the plantar surface are preferred because these areas provide enough tissue for proper puncturing while avoiding bone and are less sensitive.