A tympanic (ear) thermometer measures infrared heat radiating from the eardrum and surrounding tissues. This measurement closely approximates the body’s core temperature because the eardrum shares blood vessels with the hypothalamus, the brain region that regulates temperature. This method is popular, especially for children, due to its speed and ease of use, providing a reading within seconds. Reliable results require understanding the specific technique and potential pitfalls.
Step-by-Step Measurement Technique
Always ensure a new, clean, disposable probe cover is securely attached to the thermometer tip for hygiene and to prevent inaccurate readings. Turn the device on and wait for it to indicate readiness. The physical technique of insertion significantly influences the accuracy of the reading.
The ear canal must be straightened to provide the sensor with a clear path toward the eardrum. For adults or older children, gently pull the outer ear (helix) up and back. For infants or children under three, the ear canal is shaped differently, so the earlobe should be gently pulled down and back instead.
After straightening the canal, gently insert the covered probe into the ear opening, pointing the tip toward the eardrum. Do not force the probe, as the ear canal is sensitive. Activate the thermometer once positioned; it usually signals completion with a beep within seconds. Remove the device, read the temperature, and immediately discard the used probe cover.
Ensuring Accurate Readings
Achieving a reliable reading depends heavily on proper placement and controlling environmental variables. The infrared sensor must have an unobstructed view of the eardrum; minor misalignment can cause the reading to be lower than the actual body temperature. Consistent technique is paramount, always using the appropriate ear tug for the person’s age.
Earwax buildup (cerumen) is a common factor that can significantly interfere with the measurement. Cerumen can block the sensor’s view of the eardrum, potentially lowering the temperature reading. Lying on one ear for an extended time or recent exposure to cold air can also temporarily affect the local ear temperature.
Wait approximately 20 to 30 minutes after coming inside from a cold environment before taking a temperature. When comparing temperatures over time, always use the same ear for measurement, as a minor difference between the two ears is common. If readings are inconsistent, retake the measurement in the same ear, ensuring the probe is aimed correctly.
Care and Context for Use
Maintaining the physical condition of the thermometer is as important as using the correct technique for accurate results. The probe lens, which contains the infrared sensor, must be kept clean and free of smudges or debris. After discarding the probe cover, inspect the lens; if cleaning is necessary, use a lint-free cloth or a cotton swab lightly dampened with isopropyl alcohol.
Never submerge the thermometer in water or use abrasive cleaning agents. The exterior casing can be wiped with a mild detergent and a damp cloth, but the device must be completely dry before storage. Change the batteries promptly when the low battery indicator appears, as a weak power source can affect measurement speed and accuracy.
There are specific situations where a tympanic thermometer should not be used, as the reading will be unreliable or insertion could cause discomfort. Contraindications include suspected ear infections, known ear drainage, or recent ear surgery. In these cases, use an alternate method, like an oral or temporal artery thermometer, to obtain a safe and accurate temperature measurement.