Fever Trivia

to quote:

"What is fever, you ask? What is a normal temperature, I reply. And like every fool, you respond, "Why it's 98.6". Save me. I wish I had a nickel for every patient that said "My normal temperature is 96, so 98.6 is a fever for me." ARRRGGHHHHHHHHHHHHHHHH. You know, my mind remains boggled by the number of medical people who do not know what normal temperature is, and therefore do not know what constitutes a fever. The worst thing (well, not really) that ever happened to doctors is the red line on the mercury thermometers at 98.6.

98.6 is derived from 19th century readings with miscalibrated foot long axillary thermometers. Recent studies with modern thermometers (and every health care provider should read Mackowiak et al JAMA, 1992:268 pg 1578) reveal the following:

The maximal temperature varies from a low of 37.2°C (98.9°F) at 6 AM to a high of 37.7°C (99.9°F) at 4 PM. Please note the diurnal variation. Ovulating women (but not ovulating men) have the early morning relative hyperthermia.

Age does not significantly influence temperature.

Women have a slightly higher average oral temperature than men 36.9°C (98.4°F) versus 36.7°C (98.1°F). (are men cooler or women hotter? I'll let others decide)

Oral temperature of smokers does not differ nonsmokers.

No single temperature can be designated as the upper limit of normal.

37.2°C (98.9°F) was the maximal oral temperature (i.e., the 99th percentile) recorded at 6 AM, at 4 PM, the maximal oral temperature observed reached 37.7°C (99.9°F).

Fever is defined as an early-morning temperature of 37.2°C (99.0°F) or greater OR a temperature of 37.8°C (100°F) or greater at any time during the day.

So there."