When should a tympanic thermometer NOT be used on a patient?

A tympanic thermometer measures body temperature by sensing the infrared heat emitted from the eardrum and surrounding tissue. When a patient has an ear infection, also known as otitis media, there may be inflammation and increased fluid in the ear canal. This condition can affect the accuracy of the temperature reading obtained through the tympanic thermometer, leading to potentially misleading results.

In contrast, using a tympanic thermometer on a patient with a cold may not significantly impact the reliability of the measurement, and age or dehydration status does not inherently contraindicate the use of tympanic thermometers. Therefore, using this device is particularly inappropriate in the presence of an ear infection.