Which site is preferred for capillary puncture in infants?

The preferred site for capillary puncture in infants is the outer edge of the underside of the heel. This location is chosen because it is an area with an abundance of capillary blood vessels, making it more suitable for obtaining the small blood samples needed for testing. Additionally, the heel is away from major nerves and blood vessels, reducing the risk of complications and discomfort during the procedure.

Infants are particularly sensitive to pain, and the heel’s soft tissue allows for a less invasive and safer method of blood collection compared to other potential sites. The heel also provides sufficient depth for the lancet to access capillaries, ensuring an adequate drop of blood can be obtained effectively for tests such as newborn screening.

The inner thigh is typically avoided because it has larger blood vessels and nerves, making it riskier for this type of procedure. Similarly, using the middle finger is not appropriate in infants, as infants do not have the anatomy in their fingers for effective capillary blood collection. Lastly, any part of the forearm is also not utilized because it does not provide the same ease and effectiveness for capillary puncture in infants. Thus, the heel remains the most appropriate and safest location for this procedure in the pediatric population.