Which of the following sites is appropriate to prepare for dermal specimen collection on a toddler?

While the lateral plantar heel can be used for blood collection, it is typically reserved for infants rather than toddlers. The heel is a more sensitive area, and using a site that is less prone to discomfort and movement is preferred when dealing with young children, making this choice less appropriate.

The nondominant third finger could be a potential site for dermal collection; however, it is not as commonly used as the dorsal hand. The finger can be more difficult to stabilize compared to the larger surface of the hand, making it less ideal for obtaining a reliable specimen from a toddler.

The antecubital space, while a common site for venipuncture in older children and adults, is not suitable for dermal specimen collection in toddlers. This area is more challenging to access due to its depth and the potential for movement, plus it is often associated with a higher level of discomfort compared to the dorsal hand.