What is the appropriate depth for a capillary puncture in infants?

The appropriate depth for a capillary puncture in infants is 2.0 mm. This depth is critical because it ensures that a sufficient volume of blood is obtained while minimizing the risk of injury to underlying tissues and bones. In infants, the skin is thinner and more delicate than in older children and adults, making it essential to avoid puncturing too deeply.

When performing a capillary puncture, it's necessary to consider the anatomy of the infant's heel or finger, depending on where the puncture is made. A 2.0 mm depth strikes a balance, allowing for effective blood collection without causing unnecessary harm. Deeper punctures can lead to pain, increased potential for complications, and may also result in collecting interstitial fluid rather than blood, potentially skewing test results.

The other depth options presented may either be too shallow or too deep for an infant's delicate skin, posing various risks such as inadequate blood return or potential tissue damage. Therefore, 2.0 mm is established as the standard depth for safe and effective capillary blood collection in infants.