A non-contact infrared thermometer (NCIT) measures temperature by capturing the thermal radiation emitted by a person or object, a process known as black-body radiation. This allows for quick, hygienic temperature readings without physical touch, making it ideal for rapid screening in health and industrial settings. The device focuses infrared energy onto a sensor called a thermopile, which converts the radiant power into an electrical signal displayed as a temperature reading. Collecting thermal data from a distance, an NCIT reduces cross-contamination risk and provides results in seconds.
Preparing the Device and Environment
Proper preparation of the device and environment is necessary for accurate readings. Allow the thermometer to stabilize to the ambient room temperature for at least 10 to 30 minutes before use. If the device is moved from a cold or hot storage area, this stabilization period ensures the internal components have adjusted, which is necessary for reliable results.
The measurement area should be free of drafts, direct sunlight, and close radiant heat sources, as these external factors can interfere with infrared detection. Ensure the infrared sensor lens is clean before measurement, as dust or smudges can scatter the infrared energy and lead to inaccurate measurements. Finally, confirm the device is set to the correct mode, such as “Body” mode for human temperature checks, rather than “Surface” or “Object” mode, which uses a different calculation algorithm.
Step-by-Step Measurement Technique
Taking a reading requires precision in aiming and distance for accuracy. Most medical NCITs measure from a close distance, typically between 1 to 5 centimeters (0.4 to 2 inches) from the target. Always follow the manufacturer’s instructions to determine the optimal measurement distance.
Aim the device directly at the center of the forehead or the temporal artery area, depending on the model’s design. Hold the thermometer perpendicular to the skin, avoiding any angling that could cause the sensor to pick up surrounding temperatures. Press and hold the measurement button briefly, usually for one to three seconds, until the device signals the reading is complete. Movement during this process can compromise the accuracy of the result.
Interpreting Readings and Troubleshooting Accuracy
The displayed reading is a surface temperature, often a few tenths of a degree lower than an internal or oral temperature. While 98.6°F (37.0°C) is considered normal, a healthy range varies from 97°F (36.1°C) to 99°F (37.2°C). A reading of 100.4°F (38°C) or higher is commonly considered a fever, but consult medical guidance for definitive determination.
Misleading readings often involve external conditions affecting the forehead’s surface temperature. Sweat, hair, makeup, or facial cleansing products can interfere with the infrared signal, potentially causing a lower or inconsistent result. These obstructions should be wiped away or moved before measurement.
Measuring immediately after exercise, bathing, or being outdoors in cold weather can skew results. If a person has been exposed to extreme temperatures, they should acclimate indoors for at least 30 minutes before measurement. If a reading seems unusual, wait 30 to 60 seconds before taking a second measurement to ensure the sensor has stabilized.