What body temperature defines pyrexia?

• A. Body temperature above 100.4°F
• B. Body temperature below 95°F
• C. Exactly 98.6°F
• D. Unknown temperature

Answer: (A)

Fever happens when the body’s temperature rises above the normal upper limit. In clinical practice, any measurement that crosses that threshold is considered pyrexia, though the exact number can vary slightly depending on how the temperature is taken (mouth, ear, rectum, or underarm). The key idea is that fever is a state of higher-than-normal temperature, not a normal reading or a low reading. A reading that’s too low points to hypothermia, a normal reading isn’t fever, and an unknown temperature doesn’t tell you whether fever is present.