How to Measure Body Temperature with a Thermometer

Generally, the specific steps for measuring body temperature with a thermometer include selecting the type of thermometer, choosing the measurement site, placing the thermometer, waiting for the measurement, and reading the value. The detailed explanation is as follows:

1. Select the type of thermometer

Common types include mercury thermometers, digital thermometers, and forehead thermometers (infrared). Mercury thermometers are highly accurate but slightly more complicated to use and fragile; digital thermometers are easy to operate with intuitive readings; forehead thermometers offer rapid measurement and are suitable for large-scale screening. Choose the appropriate type based on your usage scenario and personal needs.

2. Choose the measurement site

Thermometers can measure temperature under the armpit (axillary), in the mouth (oral), or in the rectum. Armpit measurement is suitable for all age groups but slightly less accurate; oral measurement is suitable for adults and provides more accurate results; rectal measurement is more accurate for infants and young children but requires careful handling.

3. Place the thermometer

If using a mercury thermometer for armpit measurement, lift the clothing and place the mercury end deep into the armpit. Hold it firmly in place with the upper arm, ensuring full contact between the thermometer and the skin to prevent displacement. For digital thermometers, place it similarly in the armpit and hold tightly. When using a forehead thermometer, aim it at a point 3–5 cm above the center of the eyebrows, keep it steady, and press the appropriate button to prepare for measurement.

4. Wait for the measurement to complete

For armpit measurements using a mercury thermometer, maintain the position for 5–10 minutes. Remain still during this time and avoid moving the arm to prevent displacement of the thermometer from affecting the result. For digital thermometers, wait until the beep sounds, which usually takes about one minute. With a forehead thermometer, results appear instantly after pressing the measurement button. To ensure accuracy, take multiple readings and calculate the average.

5. Read the temperature value

After using a mercury thermometer, hold it horizontally at eye level and read the temperature corresponding to the top of the mercury column. For digital thermometers, simply read the value displayed on the screen. For forehead thermometers, read the digital value shown on the display. Ensure clear and accurate reading to avoid misinterpretation that could lead to incorrect assessment of health status.

Mercury thermometers are fragile and should be handled with care. If accidentally broken, properly clean up the spilled mercury to prevent mercury poisoning.