What is considered a fever in adults?

• A. A body temperature of 99.0°F (37.2°C) or higher
• B. A body temperature of 100.4°F (38°C) or higher
• C. A body temperature of 98.6°F (37°C) or higher
• D. A body temperature of 101.3°F (38.5°C) or higher

Answer: (B)

A body temperature of 100.4°F (38°C) or higher is considered a fever in adults because it typically signifies an active immune response to infection, illness, or another underlying condition. Normal body temperature can vary, but the accepted average is around 98.6°F (37°C). A temperature increase to 100.4°F or above is generally recognized by medical guidelines as a point where the body's thermoregulation indicates that a pathological process may be present, leading to physiological effects associated with fever, such as increased heart rate and changes in metabolism.

Other values provided, while they may reflect physiological changes or be slightly above the normal range, do not meet the standard definition for a fever in adults as accepted by most medical professionals and organizations.