Ear Thermometers and Proper Technique

BIOS Ear Thermometers take a reading in 1 second and have excellent instrument accuracy +/- 0.2ºC, but require proper measurement technique for reliable body temperatures.

There is a common misunderstanding that ear thermometers are inaccurate. The readings often vary because users frequently aim at the improper target. It is very important when using an ear thermometer to point the probe directly at the eardrum.

An ear thermometer measures infrared energy radiated from the eardrum and the surrounding tissue. This energy is collected through the lens and converted to a temperature value. Measurements should come directly from the eardrum or tympanic membrane.

Readings from the ear canal are not a good representation of core body temperature.

     1. Before taking measurements, remain in a stable environment and avoid               exercise and bathing for 30 minutes.

      2. Hold the child’s head so it does not move, or tell the person not to move              his/her head.

      3. For children over the age of 2, pull the ear straight back. For an adult pull            the ear straight back and up and place the probe firmly into the ear canal.            By doing this it helps to straighten out the ear canal and makes it easier              to insert the probe tip so that it is pointed at the eardrum.

Important Tips:

  • Do not bundle the baby, child or adult in clothing or blankets too tightly before taking the temperature.
  • Do not use any thermometer as a substitute for consultation with your physician.
  • Do not use an ear thermometer when a baby, child or adult has a sore ear, ear infection, or if they just had ear surgery.
  • Ensure that babies and children do not use the instrument unsupervised; some parts are small enough to be swallowed.
  • It is not recommended to use infrared ear thermometers on infants because the ear canal is not yet fully developed. If you are taking an ear measurement, be careful that the opening of the ear canal is large enough to accept the thermometer’s probe. If the probe is too large it will measure the temperature of the ear canal instead of the eardrum, the correct measurement site.


  • Always insert the thermometer in the same ear with the same direction and depth. It is recommended that you measure the temperature 3 times in the same ear. If the 3 measurements are different, select the highest one. (Allow 30 seconds between each measurement*).
  • Earwax in the ear canal may cause a lower temperature reading; therefore it is important to ensure the patient’s ear canal is clean.
  • Ensure that the tip of the ear thermometer is clean when being used. Buildup on the lens of the thermometer can cause inaccurate readings.