“The proper method of taking temperatures with the infrared thermometer is to point it at the forehead at a certain distance and to push aside any hair that may be covering the forehead,” Dr Moy Foong Ming of Universiti Malaya told FMT.

The device should be calibrated at regular intervals, she said but she noted that many low-quality brands don’t have the calibration option and could, as a result, be overused.

She advised retailers to opt for brands registered with the health ministry, saying these would have undergone quality checks.

She also advised them to train the employees assigned to conduct the temperature checks.

The normal temperature range is between 36.1 and 37.4 degrees Celsius and retailers usually prevent those showing higher readings from entering their shops.

Moy warned that temperature checks might not be foolproof even if a thermometer was working well.

“Taking temperatures right under the air conditioner may also influence the readings,” she said.

Malaysia Shopping Malls Association president Teo Chiang Kok agreed with Moy that the thermometer guns should not be overused.

“We have discovered that battery drain can lead to inaccurate readings,” he told FMT.

However, he disagreed that retailers should use only the brands registered with the health ministry.

“Thermometers should not be considered a medical device,” he said. “Unnecessary procedures of certification will bump up the price and cause delays.

“The simple use of two thermometers for the reading will solve the problem.”

CLICK HERE FOR OUR LIVE UPDATE OF THE COVID-19 SITUATION IN MALAYSIA

Fake or not? Check our quick fake news buster here.