The Pharmaceutical Journal
Vol 270 No 7248 p640
10 May 2003

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Medical device alert: infrared thermometers (PDF 240K)

Warning on use of infrared thermometers

Special advice should be given to people using infrared ear thermometers, the Medicines and Healthcare products Regulatory Agency has recommended.

Infrared ear thermometers appear to be associated with a risk of low readings if they are not used properly. They are designed to measure heat radiated from the eardrum but can also measure heat in the ear canal. A gentle but firm pull on the ear may be required to straighten the ear canal, the MHRA recommends. This stops the eardrum being obscured by the ear canal which is up to 2C cooler than the eardrum.

To straighten the ear canal in adults and children aged over one year, the ear should be pulled up and back. For children aged under one year, the ear should be pulled straight back. Once the canal has been straightened, the thermometer probe is placed into the ear canal ensuring a snug fit and aimed at the eardrum.

Another potential source of error in readings is a dirty lens on the thermometer. The MHRA says that users should ensure the lens is kept clean. It also advises that the same ear should be used for comparing temperatures. When an accurate reading is essential, it recommends using the highest of three readings.

The new guidance follows a number of reports of infrared ear thermometers falsely reassuring parents of children with high temperatures. Temperature readings appeared to be normal but subsequent readings taken on admission to hospital showed readings between 1C and 3C higher than those measured with the infrared ear thermometer.

The MHRA adds that infrared ear thermometers should always be used in accordance with the manufacturers' instructions and that users should seek medical attention if they have health concerns, regardless of the thermometer reading.

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