We are receiving many inquiries regarding the suitability of our general-purpose infrared thermometers for fever screening of employees and others.
FDA Listed Device Now Shipping
ThermoWorks WAND No Touch Digital Forehead Thermometer, our new FDA-Cleared Class II Thermometer for taking human temperatures, is now shipping.
Our Other Infrared Thermometers
ThermoWorks other infrared thermometer products are intended for food service, food processing, industrial, scientific and general home use. They are not FDA Cleared for clinical use. However, in the current pandemic environment, there is a worldwide shortage of infrared sensors and medical infrared thermometers. With proper technique, general-purpose infrared thermometers might be used as a substitute scanning tool for detecting elevated body temperatures. We offer the following information and cautions:
Forehead temperature is several degrees lower than core body temperature of 98.6 F (37 C). Clinical forehead thermometers make a mathematical adjustment to display an equivalent oral temperature. When using general-purpose infrared thermometers to read forehead temperatures, the readings will likely be lower than 98.6 F, even if a fever is present. Normal forehead skin temperature can vary several degrees depending on your environment (indoors or out), exercise, perspiration, direct heat or air conditioning, etc. It would be normal to read an actual forehead skin surface temperature between 91F and 94F if using a general-purpose infrared thermometer.
Some infrared thermometers have an “adjustable emissivity feature”. Some are factory set for emissivity of 0.95, or in the case of our IRFS, 0.97. Human skin temperature is in this range. If using a fixed emissivity infrared thermometer, one could measure temperature in the center of the forehead, and then add 5 degrees Fahrenheit to estimate the oral equivalent.
Or, to simplify things for the operator, one could measure each subject and look for a “normal” temperature of 91F to 94F without making any adjustments or offsets. A higher reading might indicate a fever. Still, such a scan could not be regarded as a reliable absolute measurement of core body temperature, only a scanning or screening indication.
Users should be aware of the “spot size” of the infrared thermometer’s measurement area. They should also consider the distance-to-target recommendations of the instrument. The angle of the sensor to the subject is also important.
If the general-purpose IR thermometer has a laser-pointing feature, it is best to turn the laser off if possible (or cover it with tape) and always use great care to avoid pointing it at someone’s eyes. The laser is not part of the measurement technology and is only used to assist in aiming.
Some industrial IR thermometers allow the adjustment of the emissivity setting. In medical literature human skin is noted to have an emissivity between 0.95 and 0.99 regardless of color. By setting an adjustable emissivity to 0.78, the instrument will give a forehead temperature reading that approximates the normal oral temperature. This approximates an “offset” to the reading that will render a measurement near 98.6 F on the forehead of a healthy individual.