Should 0.5°C be added to the armpit temperature?

Under normal circumstances, there is no need to add 0.5°C to the axillary body temperature. Detailed explanation is as follows:

In general, when using a mercury thermometer or other measuring devices to measure temperature under the armpit, the reading obtained directly reflects the actual axillary temperature. Therefore, there is no need to add an additional 0.5°C to the measured temperature. The normal range for axillary temperature is typically 36–37°C. This range is based on extensive measurement data from large populations, so no further correction of the measured results is necessary.

For routine temperature monitoring, the reading from an axillary thermometer can be used as reference. However, for more precise medical assessments—such as diagnosing fever or evaluating the severity of illness—it is recommended to use more accurate measurement methods, such as oral or rectal temperature measurement. Different individuals may have varying abilities to regulate body temperature, so assessments should be made based on each patient's specific condition. For example, children and elderly individuals have relatively weaker temperature regulation functions, and axillary temperature measurements may be subject to greater error, making appropriate correction more necessary in such cases.

To ensure measurement accuracy, it is recommended to wipe away any sweat under the armpit before taking the measurement and to hold the thermometer tightly against the skin to ensure close contact.