Using a temporal artery thermometer correctly means sliding the probe in a straight line from the center of the forehead to behind the earlobe in one smooth motion.
But if you miss the correct path across the forehead, the reading can be off by a degree or more. Temporal artery thermometers like the Exergen TAT-5000S measure heat from the temporal artery, which sits only about 2 millimeters deep on the forehead making it a fast, non-invasive alternative to rectal or ear thermometers.
How Does a Temporal Artery Thermometer Work?
A temporal artery thermometer uses infrared (IR) sensing to detect the heat radiating from the temporal artery. That artery runs across the forehead and down the side of the face near the ear. By scanning it along its natural path, the device captures core body temperature without insertion. Exergen, the leading manufacturer, designs their TAT models to lock in readings from both the forehead and the soft spot behind the ear.
What You Need Before You Start
Before taking a reading, check that the thermometer is ready and the environment is right:
- Battery: A 9-volt battery goes in with the positive terminal on the right. The device auto-off activates after 30 seconds of inactivity.
- Probe cap: Remove the plastic protective cap. Replace it after use to protect the sensor.
- Room temperature: Must be above 60.8°F (16°C). Avoid drafts, direct sunlight, or nearby heaters — they skew the reading.
- Skin condition: Hair, hats, bandages, or heavy sweat must be cleared from the scanning path. If the forehead is sweaty, skip it entirely (see step 7).
How to Use a Temporal Artery Thermometer: Step-by-Step
These instructions follow the Exergen TAT-5000S manual. The same steps apply to the TAT-2000 series and most consumer TemporalScanner models.
- Position the probe flat on the center of the forehead. Touch the probe flush against the skin at the midline. Do not press the SCAN button yet.
- Press and hold the SCAN button. Now that the probe is on the skin, depress the button and keep holding it through the entire scan.
- Slide straight across the forehead to the hairline. Move in a steady, straight line just above the eyebrow toward the top of the ear. Keep the sensor flat and in constant contact. This should take 2–3 seconds.
- Without releasing the button, lift the probe and touch the neck behind the earlobe. Place it in the soft depression just behind the ear — often called the “perfume spot.” Slide down into that hollow.
- Release the SCAN button. Remove the thermometer from the skin and read the temperature on the display. The measurement is done.
The display locks in a final number and no longer changes as you hold the thermometer. If the reading seems too low, the most common reason is broken skin contact or scanning down the side of the face instead of the straight line.
Two Common Mistakes That Skew the Reading
The two errors that cause the most inaccurate readings have simple fixes:
- Curving down the side of the face: The temporal artery runs deeper once it passes the temple. Scanning down toward the cheek instead of a straight line misses the artery’s heat. Always scan in a straight line from center forehead to hairline.
- Broken contact mid-scan: Lifting the probe even slightly introduces ambient air and cools the sensor. Keep the probe flush against the skin from start to finish. One continuous glide, no pauses.
What to Do If the Forehead Is Sweaty
Sweat on the forehead cools the skin and produces a falsely low reading. Exergen’s manual advises: skip the forehead scan entirely. Place the probe directly on the neck behind the earlobe while holding the SCAN button, then release and read. That single spot measurement is the reliable alternative when sweat is present.
Who Can Use a Temporal Artery Thermometer?
Temporal artery thermometers work for nearly every age group and body type. Research published by the NIH confirms they are effective for infants, neonates, adults, and patients who are morbidly obese or edematous — groups where other thermometers struggle. One study found the TAT reads about 0.3°C higher than rectal thermometers in neonates, placing it close to true core temperature. For infants, a single scan is often enough unless the child is visibly sweating.
Accuracy Across Skin Tones: A Caveat
Some clinical sources note that temporal artery thermometers may produce a slightly lower reading on people with darker skin tones. Infrared absorption differences are the suspected cause. If the result seems borderline, wait 30–60 seconds and re-check, or confirm with a different method.
| Specification | Detail | Importance |
|---|---|---|
| Minimum measurement time | 2 seconds (forehead scan) | Shorter scan = less fuss for wiggly kids |
| Wait time between readings | 30–60 seconds | Prevents skin cooling from the first scan |
| Fever threshold | 100.4°F (38°C) | Matches standard medical definition |
| Battery | 9-volt, positive terminal right | Standard household battery; check polarity |
| Auto-off | 30 seconds of non-use | Saves battery life |
| Room temperature limit | Above 60.8°F (16°C) | Cold rooms drop the reading |
| Probe covers | Exergen-specific caps recommended | Hygiene; some models can be cleaned without them |
Step Sequence for the Neck-Only Method (Sweaty Forehead)
When you need to bypass the forehead, the sequence changes slightly:
- Push aside any hair or clothing covering the neck area.
- Place the probe flat on the soft depression behind the earlobe.
- Press and hold the SCAN button. Slide down into the depression.
- Release the button and read the display.
The reading should stabilize immediately without the forehead segment. If the result is low, wait 30 seconds and repeat — a second attempt prevents a draft-induced error.
Cleaning and Maintenance
Keeping the sensor lens clean preserves accuracy. Exergen recommends cleaning the lens with an alcohol-moistened Q-Tip to remove debris. The protective cap goes back on after every use. For models that support it, terminal cleaning with a disinfectant wipe is acceptable between patients.
Patient Positioning: Which Side to Measure
If the patient is lying on their side (lateral position), always measure the upper side of the face. The lower side rests against the pillow, which insulates it and produces a falsely high reading. The Exergen manual and CME Corp’s guide both specify this “Up-side” rule.
| Error | Likely Cause | Fix |
|---|---|---|
| Reading too low | Broken skin contact or curved scan path | Glide in a straight line; keep probe flush |
| Reading too high | Measuring over hair, hat, or pillow side | Clear the area; measure the upper side only |
| Erratic readings | Draft, direct sunlight, or nearby heater | Move out of airflow and direct light; wait 30 seconds |
| No display | Dead battery or reverse polarity | Check 9-volt connection; positive terminal right |
Final Sequence for a Reliable Reading
For the most accurate results every time, stick to this order: clear the forehead of hair or sweat, start at the center, press and hold SCAN, slide straight to the hairline, touch behind the ear, release. Read the locked number. If the room is cold or the patient is sweating, use the neck-only method instead.
If you’re looking for a model for your family, check our roundup of top-rated options at the best temporal artery thermometers for home use to compare features and prices.
FAQs
Do you slide a temporal thermometer behind the ear?
Yes — without releasing the SCAN button after the forehead sweep, move the probe to the soft depression behind the earlobe (the “perfume spot”). Sliding into that hollow locks the final reading. Skipping this step can give a less accurate result.
What is the best position for a temporal artery thermometer?
The best starting position is flush on the center of the forehead at the midline. From there, slide in a straight line toward the top of the ear. This path follows the temporal artery where it is closest to the skin surface and gives the most reliable core temperature reading.
How do you read a temporal artery thermometer correctly?
Read the number on the display immediately after the SCAN button is released. The device locks the temperature when the button is released. If there is an obvious draft or sweat, wait 30 seconds and repeat using the neck-only method for accuracy.
Do you add a degree to a temporal thermometer?
No. Temporal artery thermometers are calibrated to read close to core body temperature. Studies show they average about 0.3°C higher than rectal thermometers in neonates, but adding or subtracting degrees is not recommended — follow the displayed number as-is.
Can you use a temporal thermometer on a newborn?
Yes — temporal artery thermometers are widely used on newborns and infants. The NIH has validated their accuracy for neonates. For a newborn, a single forehead-to-ear scan often suffices unless the baby is visibly sweating. Push aside any hair covering the neck area before measuring behind the ear.
References & Sources
- Exergen Corporation. “How to Use a Temporal Artery Forehead Thermometer.” Official manufacturer guide with step-by-step instructions and diagrams.
- Exergen Corporation. “Operation Manual – TAT-5000S Standalone USA.” Original manufacturer manual for the current medical-grade TAT model.
- WebMD. “How To Use A Temporal Artery Thermometer.” Consumer medical resource confirming usage steps and accuracy notes.
- National Institutes of Health (NIH). “Temporal Artery Temperature Measurement in the Neonate.” Peer-reviewed study validating TAT accuracy in neonatal populations.
- CME Corp. “Everything You Need to Know about Temporal Thermometers.” Professional medical equipment guide covering common errors and best practices.