Final answer:
The CLSI/NCCLS recommends a maximum skin puncture depth of 2.0 mm for an infant's heel to safely obtain blood while avoiding injury to underlying tissues and bone.
Step-by-step explanation:
The CLSI/NCCLS (Clinical and Laboratory Standards Institute/National Committee for Clinical Laboratory Standards) recommends that the depth of a skin puncture device used on an infant's heel should not exceed 2.0 mm. This is to ensure that the puncture is deep enough to obtain an adequate blood sample, but shallow enough to avoid causing injury to the baby's bone or tissues beneath the skin. It's particularly important to adhere to this guideline to prevent complications and also to ensure the comfort and safety of the infant during the procedure.