Family & health

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Digital thermometers

13feb digital thermometers default

We've tested 17 thermometers for accuracy.

Fever (or a high temperature) is often the first sign of illness. Fever is common in children – so a digital thermometer is a must-have in your first aid kit. We've tested 9 infrared and 8 digital probe models to check their accuracy and ease of use.

From our test

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Types of thermometer

You have several options when choosing a thermometer. Whichever you choose, always read the instructions to ensure you get the most accurate reading. If you’re unsure, get your doctor to show you how to use your thermometer.

  • Digital probe thermometers can be used for oral, rectal or armpit readings. Our tests show they are accurate but some are easier to use than others.

  • Ear (tympanic) thermometers are inserted into the ear canal and use infrared rays to read body temperature. They are quick and less invasive than a digital probe thermometer but must be carefully positioned to get an accurate reading. They aren’t recommended for infants under 6 months of age due to the size of their ear canals.

  • Forehead (temple) thermometers use an infrared scanner to measure forehead temperature. They are quick and non-invasive but aren’t usually considered accurate for infants under 3 months of age.

  • Mercury/alcohol thermometers contain mercury (a silvery-grey liquid metal) or alcohol (usually red). They are harder to read than digital thermometers and there’s a risk of poisoning if a mercury thermometer breaks and spills its contents.

  • Temperature strips are a plastic strip with heat-sensitive crystals that change colour to give a temperature reading. They are very easy to use but not very accurate.

What we found

Become a paying Consumer member to find out which thermometers were accurate and easy to use.

Checklist

Features to look for when you're choosing a digital thermometer.

  • The display should be easy to read. A large or backlit display is best.
  • Audible signals indicate when the thermometer is ready to use and when it has finished taking a temperature.
  • A fever indicator lets you know when a temperature is above normal.
  • Disposable sheaths keep the thermometer clean and hygienic. Though wiping the probe with sterilising alcohol between readings also does the trick.
  • A cover protects the thermometer when it’s not being used.

Temperature-taking tips

  • Avoid taking a temperature immediately after a shower or bath – the reading will be high.
  • If you’re taking someone’s oral temperature, make sure they haven’t had anything to eat or drink in the last 15 minutes (this can affect the reading). The probe should be placed under the tongue and the mouth should be closed while the thermometer’s in place.
  • For an armpit reading, the armpit must be clean and dry. Make sure the probe tip touches the skin, and then position the arm next to the body so that the room air doesn’t affect the reading. Gently hugging your child may help keep their arm in place. Armpit readings are usually 0.5°C lower than oral readings.
  • After taking someone’s temperature, wipe the thermometer with a soft cloth and warm water or mild detergent. You can also sterilise the probe tip with alcohol (but avoid alcohol contact with the battery/display end). Don’t immerse it in water unless the instructions say you can do this.
  • Digital thermometers are not toys and their batteries are hazardous if swallowed. So store your thermometer beyond a child’s reach.
  • Temperature readings with digital thermometers are only a guide and not a substitute for proper medical diagnosis. If you’re concerned, get medical advice.
 
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