Which of the following is a key indicator of infection in a patient?

The presence of an elevated white blood cell count or signs of inflammation, such as redness, heat, and swelling, serves as a key indicator of infection in a patient. White blood cells play a crucial role in the body's immune response, and an increase in their count typically suggests that the body is fighting off an infection or inflammatory process.

Furthermore, the signs of inflammation are classic responses that occur when the body is responding to an infection. These include redness (erythema), heat, swelling (edema), and pain, which collectively indicate that the immune system is activated and working to address a harmful pathogen. Monitoring these indicators is essential in diagnosing and managing infections effectively.