To truly diagnose hypothermia, an accurate body temperature reading is necessary.
There are many ways to take a temperature. Unlike the pre-digital age, when the only thermometers were glass tubes containing toxic mercury, modern thermometers can take temperatures inside and outside the body. Some can take a temperature by barely touching the patient.
- Forehead thermometers provide a simple, accurate option. Their biggest drawback is that they are expensive.
- Rectal thermometers are a bit faster and considered the most accurate at-home option for a thermometer. They are much more economical than a forehead thermometer.
- Oral thermometers use essentially the same thermometer as a rectal temperature, but must be used properly to get an accurate reading. The accuracy of an oral temperature is not as good as that of a rectal temp. Using an oral thermometer and taking the temperature under the arm (axillary) is extremely inaccurate and not recommended.
- Tympanic thermometers (in the ear) that can be obtained over the counter are fast but notoriously inaccurate. These do not make contact with the tympanic membrane like the professional versions do and require proper use to work correctly.