An infrared (IR) thermometer gun is a quick, non-contact tool that measures temperature from a distance. These devices capture the natural infrared energy emitted from a surface, which is a form of thermal radiation. This technology allows for rapid screening, making it a popular choice for home use and public health settings. The instrument measures the skin surface temperature and uses an internal algorithm to estimate the body’s core temperature.
Preparing the Device and Environment
Achieving an accurate temperature reading requires preparation. A common source of error is a dirty sensor lens, which blocks the infrared energy being collected. The lens should be gently cleaned with a soft cloth or cotton swab, using alcohol if necessary, and allowed to dry completely. The device should also adjust to the surrounding conditions, ideally sitting in the testing room for 10 to 30 minutes if stored elsewhere.
The immediate environment significantly influences the result, so measurements must be taken in a stable setting. Avoid taking a reading near strong drafts, direct sunlight, or radiant heat sources like heaters or air conditioning vents. The skin surface of the person being measured needs to be dry and clear of obstruction. Ensure the forehead is free from sweat, cosmetics, or hair, as moisture and barriers interfere with infrared energy emission.
Step-by-Step Guide to Taking a Temperature
Power on the device and confirm it is set to the correct measurement mode. Most medical IR thermometers have a dedicated “Body” or “Forehead” mode, which activates the internal adjustment feature to calculate an oral-equivalent temperature. Using the “Object” or “Surface” mode will only display the raw, lower skin temperature reading, leading to a false result.
Once the correct mode is selected, position the thermometer at the proper distance from the person’s forehead. The optimal range is typically between 1 and 6 inches, though manufacturer instructions often specify a target distance like 1 to 2 inches. Hold the device perpendicular to the center of the forehead, between the eyebrows, ensuring the sensor lens is aimed directly at the skin.
With the thermometer properly positioned, press and hold the measurement button or trigger until the device registers a reading, often signaled by a beep. It is recommended practice to perform three consecutive measurements in the same spot. This technique helps mitigate random error from a single reading caused by slight movements or momentary environmental fluctuation.
After taking the three readings, the most accurate result is obtained by calculating the average of the three numbers. This method provides a more stable and reliable estimate of the subject’s temperature than relying on a single, potentially anomalous, data point.
Understanding and Interpreting Temperature Readings
The reading displayed on the screen is an estimate of core body temperature. The normal range for an IR thermometer, after its mathematical adjustment is applied, typically falls between 97.0°F and 99.5°F (36.1°C to 37.5°C). It is important to know whether the device is set to Fahrenheit or Celsius, as most models offer a simple toggle button to switch between the two scales.
The skin temperature measured by the device is naturally lower than an internal temperature. If an IR thermometer did not apply an offset, a healthy person’s forehead reading might be closer to 91°F to 94°F. Variation in readings can occur due to physiological factors such as recent exercise, which raises skin temperature, or the presence of sweat, which lowers it due to evaporative cooling.
Variations can also be caused by external influences, such as coming indoors from cold weather or the presence of a strong airflow. If a reading seems unusually high or low, wait a few minutes for the person to stabilize in a neutral environment and then re-measure. A temperature consistently elevated above the normal range is an indication to seek professional medical advice.