Final answer:
When a patient has both first and third degree burns at the same site, only the code for the third degree burns is reported since it represents the more severe injury.
Step-by-step explanation:
If a patient has both first and third degree burns of the same site, the correct coding would involve reporting only the code for the more severe burn, which is the third degree burn. Thus, the correct answer to this question is D. Only a code for the third degree burns is reported.
The rationale behind this coding decision is that third degree burns are the most severe, fully extending into the epidermis and dermis, destroying tissue and affecting nerve endings and sensory function. Whereas, first degree burns are superficial and typically heal on their own. Therefore, coding protocols dictate that in cases where multiple degrees of burns are present at the same anatomical site, only the code for the most severe degree of burn is reported.