Final answer:
In response to a patient with body aches, fever, and crusty sores, an RN should check for medication allergies and consider performing a rapid strep test along with discussing with a physician about ordering a full blood count test.
Step-by-step explanation:
When a patient presents to the ER with body aches, a fever of 101F, and crusty painful sores on his lips, the registered nurse (RN) should perform a thorough assessment including checking for allergies to common medications. This is vital to ensure that any drugs administered do not cause an adverse allergic reaction. Additionally, given the symptoms, it would be prudent for the RN to perform a rapid strep test since the patient exhibits some signs consistent with a streptococcal infection. However, the presence of sores on the lips might also suggest a viral etiology such as herpes simplex. The RN should not only rely on this test alone but also consider the full clinical picture, and perhaps discuss with a physician the possibility of initiating a full blood count (FBC) test to diagnose or rule out other potential infections or systemic conditions that could explain the symptoms.