THE MYTH OF 98.6: A VITAL SIGN TAKEN FOR GRANTED

For over a century, 98.6°F/37°C has been commonly accepted as the benchmark for normal body temperature. In addition, 100.4°F/38°C has been the threshold for a fever. However, a growing body of evidence suggests these values are outdated and oversimplified. These values, derived in part, from Carl Wunderlich's nineteenth-century work, fail to account for modern data, circadian variation, and individual baseline differences. Contemporary studies reveal a lower average body temperature, and this suggests a need for redefining body temperature thresholds. Despite the clinical significance of this vital sign, it remains inconsistently defined across clinical guidelines. Recognizing abnormal body temperature as a spectrum rather than a fixed threshold may improve diagnostic accuracy and ultimately patient outcomes. This paper challenges the historical fixation surrounding 98.6°F/37°C and 100.4°F/38°C, calling for a modernized, context-driven approach to temperature interpretation.