A temporal thermometer is a non-invasive device that uses an infrared sensor to measure heat radiating from the temporal artery, a blood vessel located just beneath the skin of the forehead. Because this artery is close to the surface, it provides a reliable reflection of the body’s core temperature. The device is popular for home use as it offers a fast, comfortable, and hygienic method for temperature assessment, often yielding a reading in seconds. This ease of application makes it a preferred alternative to more invasive methods, especially for sleeping infants or uncooperative subjects.
Preparing the Device and Patient
Before attempting a measurement, ensure the device is ready and the reading surface is optimized for accuracy. The sensor lens, which is responsible for capturing the infrared energy, must be clean and shiny to prevent interference with the heat signal. A dirty or smudged lens can cause a falsely low reading. It is also important to check the battery life, as a low charge can affect the device’s consistency.
The patient’s forehead must be dry and clear of any obstructions. Sweat or moisture on the skin introduces an evaporative cooling effect, which artificially lowers the surface temperature detected by the sensor. Hair should be gently moved aside to expose the entire forehead, particularly the area near the temple where the artery is most accessible.
Step-by-Step Measurement Technique
The technique involves a specific scanning motion that tracks the temporal artery across the forehead. Begin by placing the probe lens flat against the center of the forehead, midway between the eyebrow and the hairline. Press and hold the scan button to activate the infrared sensor.
While continuously holding the button, slowly slide the thermometer in a straight line across the forehead toward the temple and the top of the ear. This motion ensures the device captures the peak temperature over the artery’s path. Releasing the scan button too early will interrupt the measurement process and may result in an inaccurate, lower temperature display.
For many models, especially if the patient is sweating, the final step involves lifting the probe from the forehead while still holding the button down. Briefly touch the probe to the soft depression on the neck just behind the earlobe. This second scan point compensates for evaporative cooling loss and helps determine the most accurate core temperature. Release the scan button only after this final contact to read the displayed result.
Understanding and Validating Temporal Readings
A temporal temperature reading reflects the surface heat of the temporal artery, which indicates core body temperature. Temporal readings may naturally be slightly lower than temperatures taken rectally or orally. The key is to establish a personal baseline through consistent use of the same device and technique.
External factors can significantly influence the reading, requiring validation if the result seems unexpectedly low or high. Sweat is a common issue, as it cools the skin and can cause the thermometer to underestimate the actual temperature. Lying on one side of the head or recent physical exertion can also temporarily skew the surface temperature. If these variables are present, take a second reading on the opposite side of the forehead to ensure accuracy. A temperature of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher is recognized as a fever.
Cleaning and Storing Your Thermometer
Proper maintenance is necessary for both hygiene and continued accuracy. The sensor lens should be cleaned after each use, especially if it has made direct contact with the skin. Use a cotton swab or cotton ball lightly moistened with an alcohol solution, such as 70% isopropyl alcohol, to gently wipe the lens area.
It is important to avoid using abrasive materials or harsh cleaning agents directly on the lens, as these can leave a residue or scratch the delicate sensor surface. The body of the thermometer can be wiped down with a disinfectant wipe, but water should not enter the electronic components. Store the thermometer in a dry location, away from direct sunlight and extreme temperatures, to preserve longevity.