Which sign or symptom would be most indicative of infection in a postoperative patient?

The most indicative sign or symptom of infection in a postoperative patient would be redness, warmth, and tenderness at the incision site (option C). These signs suggest inflammation and possible infection at the surgical site, which can be a source of serious complications in postoperative patients. Monitoring the incision site for these symptoms is crucial in identifying early signs of infection and allowing for prompt intervention.

Options A, B, and D are not as specific or direct indicators of infection at the surgical site. While the presence of an indwelling urinary catheter (option A) can increase the risk of a urinary tract infection, it is not the most indicative sign of infection at the incision site. A rectal temperature of 100° F (37.8° C) (option B) may indicate a low-grade fever, which could be a sign of infection but is less specific than the physical signs at the incision site. Similarly, a white blood cell count of 8,000/mL (option D) within normal range alone may not be a definitive indicator of infection without correlating clinical signs of inflammation at the incision site.