What can happen if a capillary puncture is too deep in infants?

A capillary puncture that is too deep in infants can indeed cause damage to underlying structures, making this the correct answer. In infants, the anatomy of the fingers or heels (the common sites for capillary sampling) includes delicate bones, nerves, and blood vessels positioned closely to the surface of the skin. If the puncture is too deep, the lancet can inadvertently penetrate these structures, potentially leading to serious complications such as bleeding, infection, or long-term damage.

Other options are also relevant but not entirely correct. For instance, while penetrating too deeply could lead to inadequate blood collection, this is not the primary concern; the main issue is the risk of tissue damage. The potential for causing severe pain exists, but this is secondary to the actual physical harm that could result from a deep puncture. Additionally, a deep puncture does not ensure a sufficient blood sample—in fact, it raises the risk of complications without guaranteeing an adequate volume of blood collected. Consequently, careful technique and an understanding of an infant's anatomy are crucial in performing capillary blood collection safely.