1. Drinking hot or cold fluids, exercising, smoking or performing other activities can raise or lower the subject's temperature. Therefore, it's important that the subject relax for approximately 5 minutes with the mouth closed prior to taking a reading.
2. If the temperature is measured in vivo, the subject's mouth must remain closed to obtain an accurate reading. Opening the mouth can result in an extended measurement time that can affect the reading.
3. Taking two readings in quick succession can cause the second reading to be low since the thermometer will "draw down" the temperature of the oral heat pocket during the first reading.
4. Temperature variables in the mouth can cause the reading to be more than one degree Fahrenheit (1.0°F) lower than the subject's actual temperature.
5. Normal body temperature can vary by two degrees Fahrenheit (from 97°F to 99°F).
6. A thermometer designed to calculate peak temperature using a predictive model assumes a constant rate of temperature increase and always stops in a fixed amount of time. If the rate of temperature increase isn't constant, predictive thermometers will give an incorrect temperature.
Faichney digital thermometers are actual read thermometers that calculate actual temperature and stop when peak temperature is reached.
7. For the most accurate in vivo temperature measurement: