Infrared Thermometers for Measuring Skin TemperatureTraditional mercury or digital thermometers are used by placing the instrument inside an object — most commonly, in your mouth under your tongue. Infrared thermometers, on the other hand, allow temperature to be measured without contacting the object (or your body) at all. When triggered, light bounces off the surface of the object and detects radiation emitted from the object. The thermometer then infers the temperature based on that electrical emission with impressive accuracy. For example, ICI’s non-contact thermometer has an accuracy of ± 0.3 °C / ± 0.5 °F. Depending on external circumstances, the thermometer can be as accurate as ± 0.2 °C / ± 0.4 °F. It is important to note the distinction that these thermometers are measuring skin or surface temperature and not internal temperature. A high surface temperature could be caused by a fever, or it could be caused by sitting outside on a hot day. Think about the difference in internal versus surface temperature when cooking. Your steak might have a very high surface temperature from its direct contact on the grill, but its internal temperature may still be low and nearly raw.
How Does an Infrared Thermometer Work?Liquid thermometers, commonly containing mercury, provide a readout when the liquid expands in response to heat. An RTD digital thermometer contains a sensor that computes temperature change. What distinguishes the IR thermometer is that it focuses infrared light at an object to detect and measure energy or radiation coming from its surface. The detector then translates the amount of electricity generated into a temperature reading.
How to Use an Infrared ThermometerThe process of obtaining an accurate measurement using an IR thermometer is simple, but proper usage is critical for obtaining the best results. For instance, where one points the thermometer matters. When measuring body temperature, the warmest part of the human body is actually located in the inside portion of the eye, and not on the forehead as many commonly believe. This is where you should point the thermometer. Fun fact: This is the most accurate location due to a vein that runs directly from the heart’s aorta to the inner corner of the eye. To safely take temperature in the inner canthus, follow these steps:
- The patient should be steady and not moving around.
- The patient’s eyes should close while the physician lines up the laster.
- Physician turns off the laser.
- Patient reopens his or her eyes.
- Physician takes the temperature.