Ear Thermometer - FAQ's

Where should I take the temperature?


The most reliable core temperature is obtained by inserting a thermometer into the rectum.  Normal range is approximately 36.2°C - 37.7°C.


This is a very reliable method of measuring core temperature using an ear thermometer as it detects the infrared heat given off by the ear drum.  Normal range is approximately 35.5°C - 37.5°C.


Oral temperature measurements can be taken 'in the cheek' (buccal) or 'under the tongue' (sublingual).  Both of these measurements show slightly lower temperatures than the rectal method (0.3°C - 0.8°C), but the under the tongue method is preferred over the cheek method.


Used in clinical practice, in the armpit (axillary) and in the groin method are successful to a limited extent and the measurement time is longer. Axillary measurements are lower than the rectal method by as much as 0.5°C - 1.5°C.  In infants, when compared to rectal measurements, these temperature differences are much smaller.

What is considered to be a 'normal' temperature?

Tempeature ranges may differ according to age group and the following is a guide based on oral measurements:

Group Temperature Range
 Babies & toddlers ages 0 - 2 36.4°C - 38.0°C
Children age 3 - 10 36.1°C - 37.8°C
Young people and adults age 11 - 65 35.9°C - 37.6°C
Adults over the age of 65 35.8°C - 37.5°C

Note: Among older people there can be large variations in temperature - always consult with your GP if you have any concerns.

Why do I get a low reading when using an ear thermometer?

Generally, low readings are caused by the technique used when taking a temperature.  It is suggested that you practice on yourself when you are feeling well so that you can be confident of accuracy when taking someone else's temperature when they are ill.

How do I keep the probe lens on the ear thermometer clean?

You should use a new probe cover each time the thermometer is used to take a reading.  Do not use the ear thermometer without a probe cove as the lens has the potential to become dirty which will impact the accuracy of the measurement.  If the probe lens should become dirty, you can clean it gently with a soft cotton cloth moistened with alcohol.  Do not use a paper towel as the paper fibers may scratch the lens.  Allow the lens to dry thoroughly before use (approx 45 minutes).  Keep the ear thermometer in its protective case when not in use.

What replacement battery do I need for the GentleTemp ear thermometer?

The GentleTemp ear thermometer uses a single 3V lithium battery type CR2032.  Ensure the orientation of the battery (+ and -) when replacing.