Where should I take the temperature?

The most reliable core temperature is obtained by inserting a thermometer into the rectum (rectal measurement). This measurement is accurate and has low scattering in the results. The normal range is approx. 36.2°C – 37.7°C.

In women, vaginal temperature measurement yields a slight underestimate of temperature by an average of 0.1°C to 0.3°C in comparison with a rectal measurement with comparable stability.

The oral measurement can be performed as a buccal measurement (in the cheek) or as a sublingual measurement (under the tongue). Both measurement underestimate the rectal temperature by approx. 0.3°C to 0.8°C, with the sublingual measurement being preferable to the buccal.

The only types of body surface temperature measurement used clinically in practice are the arm pit (axially measurement) and in the groin (inguinal measurement). In both cases, the respective limb is pressed against the body in order to reduce any ambient temperature influence. However, this is successful only to a limited extent with the disadvantage that the measurement time is long. In adults, the axillary measurement is lower than the rectal by approx. 0.5°C to 1.5°C!

In infants, these underestimates in comparison with the rectal temperature are much smaller.

Contactless thermometers measure the radiant heat emitted by heat source. The surface temperature can be deduced from this radiation. Today manly ear thermometers are in use. They aim to quickly measure the temperature of the ear drum.