How to Use an Infrared Ear Monitor

Infrared baby thermometer


Infrared ear thermometer

Infrared ear thermometer is an excellent tool for taking body temperature, especially for a baby or a hyperactive kid. The infrared ear thermometer can take an accurate reading within one second. No other thermometers can do this. Unlike an oral thermometer, you can take the temperature while the baby is asleep. However you have to know how to use the thermometer correctly; otherwise the reading may be off.

How to use an infrared ear thermometer

An infrared ear thermometer derives the body temperature by remotely detecting the eardrum temperature. The key to an accurate measurement is to make sure that the infrared sensor points at the eardrum and there is nothing in between. Any path blockage would interface with the amount of radiation received by the sensor leading to a lower reading. Pay attention to the following points when using an infrared ear thermometer.

outer ear
  • Gently pull the ear back to straighten the ear canal. For some people, their ear canals are curved slightly and this would prevent pointing the sensor directly at the eardrum.
  • When positioning the probe into the ear canal, make sure it aims at the eardrum. If the probe points to the ear canal wall, the reading may be off slightly.
  • If the ear canal is blocked by earwax, fluid or other material, this would interfere with the radiation reaching the sensor.
  • If the sensor is not clean, reading would be off as some radiation would be blocked by the dirt.

If you suspect the result, take a few more readings and make sure that you use the proper technique. Consistent readings are dependent on using the same technique to do the measurement.

How an infrared ear thermometer works

The thermometer measures the infrared energy emitted from the patient's eardrum and computes the body temperature based on a formula. The eardrum temperature is a very reliable and accurate indicator of the body temperature. The eardrum is recessed inside the head and is less affected by external temperature. It situates close to the hypothalmus, which regulates a person's body temperature. The eardrum is an ideal place for taking temperature.

Measuring the eardrum temperature directly is difficult as it is embedded with the ear and it is very fragile. The alternative is to measure the temperature remotely. All objects, with the exception of those at absolute zero, emits radiation. The intensity and frequency of the radiation depends on the object's temperature. When an heating element inside an oven gets hot, it glows with reddish color and you can feel the heat. This is the energy radiated by the heating element at a high temperature. At lower temperature, the radiation frequency spectrum is at the infrared range, not visible to our eyes.

At the end of an infrared ear thermometer is a lens for focusing the infrared energy on to a thermopile, normally made of a thin pyroelectric crystal. The crystal generates an electric charge proportional to the amount of energy received and a temperature measurement is obtained based on the amount of electric charge generated.