Product FAQs

How Do Temporal Artery Thermometers Work? (FAQ)

Is the TemporalScanner™ a non-contact thermometer?

No.  The Temporal Artery Scanner must make contact with the skin and the probe head must be flush to the surface of the skin at all times during the scan across the forehead, and also behind the ear if using the device behind the ear.

What does the TemporalScanner™ Measure?

With a gentle scan of the forehead, the TemporalScanner measures temperature by capturing the naturally emitted heat from the skin over the temporal artery, taking 1,000 readings per second, selecting the most accurate.

With its patented Arterial Heat Balance system, the TemporalScanner measures ambient temperatures mathematically replaces the small temperature loss from cooling at the skin and displays an accurate arterial temperature.

How does the TemporalScanner Thermometer Work?

Image of Temporal ArteryAs you gently stroke the thermometer across the forehead crossing over the temporal artery, the sensor in its probe performs two processes. Here's how it works:

  • First it scans like a video camera, capturing naturally emitted infrared heat from the arterial blood supply at about 1000 “frames” per second, locking in the highest temperature it senses and;
  • Second, at the same time, a patented system measures the ambient temperature of the site where the temperature is being taken. The patented “arterial heat balance” (AHB) software then synthesizes the two separate readings to accurately determine and display body temperature.
  • As with any thermometer, taking temperatures properly is critical to obtaining accurate temperatures. To avoid inaccuracies, please read all instructions carefully and thoroughly before using this product.

How Should I Use Exergen Temporal Thermometers to Get an Accurate Temperature?

To ensure accuracy of temporal artery thermometers, you must properly scan the temporal artery.

Slide the thermometer in a reasonably straight line across the forehead, midway between the eyebrows and the upper hairline. Do not slide down the side of the face. Midway on the forehead area, the temporal artery is less than 2 millimeters below the skin surface, down the side of the face. It is much deeper and less accurately measured. Choose the side of the head that is least exposed.


Why Are Temporal Thermometers More Accurate than Ear Thermometers?

A major reason ear thermometers are considered inaccurate by medical professionals is because the positioning of the probe in the ear canal is inconsistent, thus creating inconsistent readings and frequently missing fevers. The temporal artery thermometer scans the forehead area for the temporal artery and it is almost impossible to miss the artery during a scan.

Also, the person whose temperature is being taken does not like something inserted in their ear, making good positioning even more difficult. The gentle scan across the forehead is comfortable and not objectionable. The TemporalScanner thermometer has been proven more accurate than ear thermometers by a Harvard Medical School study.

What is the Arterial Temperature?

Arterial temperature is the same temperature as the blood flowing from the heart. It is the best determinant of body temperature.

Why Take Temperature Measurements at the Skin Surface over the Temporal Artery?

Infant Forehead The best place to measure temperature is the center of the heart, but this can be done only under a doctor's supervision. Doctors know that measurement of the blood temperature in a major artery accurately reflects true body temperature. The TemporalScanner Thermometer is designed to measure the temperature of the skin surface over the temporal artery, a major artery of the head.

The temporal artery is connected to the heart via the carotid artery, directly leading from the aorta, the main trunk of the arterial system. It offers constant blood flow. It is the only such artery positioned close enough to the skin surface to provide access needed to take an accurate measurement. It is easy to use because it is ideally located at the front portion of the forehead. The TemporalScanner is easier and gentler to use than other types of temperature measurement devices, such as oral, rectal, underarm and in-ear thermometers, because it is truly non-invasive.

Normally, How Does Arterial Temperature Compare to Other Methods of Temperature?

Arterial temperature is the same temperature as the blood flowing from the heart. It is the best determinant of body temperature.

The temporal arterial temperature method eliminates any discomfort that would be caused by a thermometer inserted into the ear, mouth, or rectum. 

Is Temporal Arterial Temperature Different When Someone is Sick?

Using the temporal artery temperature method, you can, at times, expect larger differences from temperatures taken at other body sites. This is because of two main reasons:

  • Temporal artery temperature changes faster than a temperature taken rectally
  • Temporal artery temperature is not affected by the things that cause oral and underarm temperatures to be misleading.

For example, drinking, coughing, talking, or mouth breathing can easily affect oral temperature, and skin blood flow changes with a fever can easily affect axillary temperature.

Why am I Getting Inconsistent Results?

You should normally be getting reproducible results, or results within a few tenths of a degree of each other. However, a few things to know:

  • Multiple temperatures taken over the same area in rapid succession will ultimately cool the area, causing differences.
  • If sweating, the temperature on the neck behind the ear lobe becomes the overriding temperature, and since this area is not quite as stable as the temporal artery, it can easily be cooled by the thermometer in taking multiple readings. Remember, the probe of the thermometer will be at room temperature, and is about 30 degrees Fahrenheit (17 degrees Celsius) cooler than body temperature.

These instances can cause inaccuracies using the temporal artery temperature method. Learn more about why you may be getting different temperature readings here.

I Heard the Thermometer is Sensitive to Ambient Temperature, is it?

Yes, it is sensitive to ambient temperature, which is part of the reason it is so accurate. But, as long as the thermometer is approximately the same ambient temperature as the individual whose temperature is being taken, you don't have to be concerned.

Doesn't Ambient Temperature Affect the Temperature of the Skin on the Forehead?

Yes, ambient temperature affects the skin temperature, and so the thermometer automatically measures the ambient temperature at the very same time it is measuring the temperature over the temporal artery. It then can calculate any heat loss (in a normal or cold room) or gain (in a hot room), and instantly computes an accurate body temperature. Exergen patented this method, which is called the Arterial Heat Balance Method, and the result, proven by clinical studies, is a non-invasive body temperature as accurate as even the most invasive temperature measurement methods.

What Else Should I Know?

  • As mentioned earlier in this FAQ, measure only the side of the head that is most exposed. Any covering, hair, hat, etc., will prevent the heat from dissipating and would cause the reading to be inaccurately high. This also applies if one side of the head is into a pillow.
  • Cleaning your thermometer will ensure you get the most accurate results.
  • You should also know you have purchased the gentlest and most accurate method of temperature assessment in the world.

Where can I Purchase a TemporalScanner?

You can buy Exergen products on our store online, including the TAT-2000C temporal artery thermometer.

The TemporalScanner is available at Costco, Wal-Mart, Target, and Walgreens presently. See more here.


Buy Online

You can buy the Exergen TAT-2000C on our website, or at select retail stores.


Proven Accuracy

Over 100 Peer-Reviewed Published Papers, Abstracts, and Letters on Temporal Artery Thermometry.


Buy Now

Purchase the Exergen TAT-2000C directly from the Exergen Store, or at one of several major retail locations.


Consumer Product Customer Service

Need help with a return, or questions about how to properly use your device? We're here to help.