Comprehensive Core Nursing Practice Test 2026 - Free Nursing Practice Questions and Study Guide

Elevated body temperature is a recognized sign of infection, commonly referred to as fever. The body often responds to infection by raising its temperature in order to create an environment that is less hospitable for pathogens. This physiological response is part of the immune system's mechanism to fight off invaders such as bacteria and viruses. When the body detects the presence of these pathogens, it can produce pyrogens that signal the hypothalamus to increase the body temperature.

The other options do not indicate infection in the same way. Decreased appetite can occur for many reasons, including stress or illness, but it is not specific to infection. A decreased heart rate is generally not associated with infection; in fact, many infections can lead to tachycardia as the body attempts to maintain adequate blood flow. Increased energy levels typically do not correspond to infection, as infections often lead to fatigue and malaise due to the body’s resources being redirected to fight the illness. Hence, elevated body temperature is a clear and direct indicator of an infection in a patient.