Are Infrared Thermometers Accurate?

The forehead thermometers can make taking a sick child’s temperature fast and easy. But children can ruin a reading by shaking their heads, the accuracy of a thermometer depends on correct use.

How accurate are infrared thermometers?

Forehead thermometers, which typically cost about $40 to $80, use an infrared sensor to measure the heat from the forehead. The devices’ readouts are designed to equal oral or axillary temperatures.

The infrared thermometer is held an inch from the forehead, then touched behind the ear to get an additional reading.

The readings are nearly instantaneous, companies say, and the method is so gentle, it can be done on sleeping children. The forehead skin is over the temporal artery, which carries blood from the heart—making it an ideal place to measure core temperature.

Some studies have found forehead thermometers highly accurate, while others found them not as reliable as rectal thermometers—considered the gold standard by many physicians.

“Parents should use the temperature-measuring device that they feel comfortable”

The children were also more comfortable compared with the rectal temperature which “made them fussy”.

The company says its ear thermometer—an older model that measures the heat emanating from the eardrum—is slightly more accurate than its forehead model.

“When you care about each tenth of a degree, you want to turn to your ear thermometer”

A limitation of the forehead thermometers is they won’t be accurate if the person is sweating since sweat cools the forehead skin.

Wait until the person stops sweating, or use another thermometer, companies say. Also, tell your doctor which model you used.

The infrared thermometers give readings similar to rectal temperatures, the companies say; while, the forehead thermometer is calibrated to approximate an oral temperature, about nine-tenths of a degree Fahrenheit lower.

Most accurate way to take temperature in adults

You can take a temperature using the mouth (oral), armpit (axillary), or ear (tympanic). But the temperature readings vary depending on which one you use, and you need an accurate body temperature to determine if a fever is present.

Medical research hasn’t determined an exact correlation between oral, ear, armpit, and forehead temperature measurements. Generally, the correlation between temperature results are as follows:

• An ear (tympanic) temperature is 0.5°F (0.3°C) to 1°F (0.6°C) higher than an oral temperature.
• An armpit (axillary) temperature is usually 0.5°F (0.3°C) to 1°F (0.6°C) lower than an oral temperature.
• A forehead (temporal) scanner is usually 0.5°F (0.3°C) to 1°F (0.6°C) lower than an oral temperature.

It is important to remember:

• The manufacturer of the temperature device you use, such as an ear or forehead thermometer, provides information on how to use it.
• Be sure to read and follow the instructions to obtain an accurate temperature.
• The information may also include how the results of the device correlate with the results from other methods of taking a temperature.

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