Wed | May 5, 2021

Garth Rattray | Non-contact infrared thermometers are safe

Published:Monday | January 25, 2021 | 12:06 AM
In this August 2020 file photo, an infrared thermometer is seen near the entrance at Boys & Girls Club of Hollywood in Los Angeles.
In this August 2020 file photo, an infrared thermometer is seen near the entrance at Boys & Girls Club of Hollywood in Los Angeles.

Far too many people willingly accept whatever drivel is meted out to them as irrefutable facts. Sadly, it’s now become fairly common for charlatans, demented, misguided, or attention-seeking nuts to don farcical façades virtually and splash rubbish all across the Internet.

Adolf Hitler coined the term ‘Big Lie’ in his 1925 book, Mein Kampf. Hitler said that the use of a colossal lie would have people believing that no one “could have the impudence to distort the truth so infamously”. That same Big Lie principle is very active and extremely dangerous in today’s digital age. I can’t figure out why any sane human being would derive some sort of sick satisfaction from knowing that he/she is propagating harmful lies and falsehoods that influence innumerable millions all over the world.

One such well-scripted, digitally produced, widely disseminated and ridiculous machination resulted in the distrust of non-contact infrared thermometers (NCITs) as it pertains to their use in taking the temperature from the forehead. A social media video claims that a so-called ‘medical doctor’ warns that pointing the NCIT at the forehead is dangerous and will damage the pineal gland. As a result of this warped, whimsical lark, most NCIT devices are now pointed at the wrist, hand or forearm.

The rationale for checking for a fever is grounded in its association with the presence of active SARS-CoV-2 infections. Fevers occur when our thermoregulatory centre in the hypothalamus resets our core body temperature to above the normal set point. This is usually caused by pathological processes and the presence of pyrogens – immunological mediators from micro-organisms, some medications, some cancers, chemicals, or internal inflammatory processes that trigger our thermostat reset.

Fevers are naturally mounted responses to counteract disease processes. Fevers enhance immune function, increase motility and activity of our white blood cells, stimulate interferon production and activation of our immune system T-cells. Fevers also inhibit the growth of some microbial agents. However, high fevers can be extremely dangerous in many ways. Our normal body temperature is about 37 degrees C +/- 0.5 degrees. There are minor core temperature fluctuations throughout the day. Of special mention is the poor febrile response in the elderly. Their ability to develop a fever is impaired, so a modest fever may mask the presence of a raging infection.

A fever and hyperthermia (the elevation of the core temperature beyond the limits of our thermostat set point) are very dissimilar.

In the everyday world, the temperature may be taken with a glass tube (mercury), digital, plastic strip, pacifier or an infrared thermometer. Glass tube (mercury) and digital thermometers are used for rectal, oral, or underarm measurements. Infrared thermometers are used for eardrum and forehead measurements. When it comes to accuracy, the closest to our core temperature is the rectal, then eardrum, then oral, then armpit and lastly, the forehead. No research mentions measuring the temperature from the wrist, hand or forearm.

Calling a reading a fever is tricky business because it varies according to age. Some guidelines define a fever in children as an oral reading of 38 degrees Celsius. In young to middle-age adults, an oral temperature greater than 37.7 degrees Celsius is a fever. For the elderly (over 65-years-old), any persistent oral temperature over 37.2 degrees Celsius represents a fever.

Obviously, temperature measurements on the forehead with a NCIT is the least accurate; however, it is frequently used in these COVID-19 times because it is the least invasive and allows for the caution of physical distancing. But it is fraught with inaccuracies and variability according to the distance from the object, ambient temperature, sweat, oily skin, previous exposure to outdoor heat or air conditioning and nearby electronic devices.

Infrared thermometers do not emit anything, they detect the natural infrared radiation that our bodies give off. People forget that airport body temperature scanners and eardrum thermometers (both have been in use for many years) also employ infrared technology. Infrared thermometers are completely harmless. In fact, snakes, frogs/toads, blood-sucking insects like bed bugs and mosquitoes, and fish also detect infrared to locate their ‘food’.

It is therefore totally impossible for any NCIT to penetrate anything, let alone deep, deep into the brain, through skin, fat, muscle, bone, and brain tissue to reach the pineal gland! When security guards announce that my body temperature is 32 degrees Celsius, after aiming the NCIT at my hand, wrist or forearm, I sometimes smile and tell them that I am a reptile. The sad part is that aiming at anything but the forehead reduces the accuracy of an already-less-than-accurate device. The bad news for us all is that they are obviously missing many people with fevers all because of a silly Internet video.

Garth A. Rattray is a medical doctor with a family practice. Email feedback to columns@gleanerjm.com and garthrattray@gmail.com.