What’s up with the temperature sensor on the Pixel 8 Pro?

Temperature sensor. Temperature sensor? Temperature sensor. | Image: Google

The Pixel 8 Pro has an infrared temperature sensor. Why does the Pixel 8 Pro have a temperature sensor?

For an unusual feature on a $1,000 flagship phone, Google really isn’t saying much about it. The Pixel 8 Pro announcement mentions it almost in passing:

And on the back of the Pixel 8 Pro, a new temperature sensor lets you quickly scan an object to get its temperature. Use it to check if your pan is hot enough to start cooking or if the milk in your baby’s bottle is at the right temperature. We’ve also submitted an application to the FDA, to enable Pixel’s Thermometer App to take your temperature and save it to Fitbit.

Any off-the-shelf infrared thermometer can tell you the temperature of a hot pan or a baby bottle. But the instant you point it at a human being and start saying you’re measuring body temperature, congratulations: that’s medical data, you’re a Class II medical device, and you need Food and Drug Administration clearance.

Here’s where it gets a little bit complicated: Google doesn’t need clearance for the phone itself, or even for the temperature sensor per se. Technically, it doesn’t even need clearance to read your skin temperature as long as it’s using the data for something other than telling you your body temperature. (Several companies already use infrared temperature sensors built into smartwatches for sleep tracking and cycle prediction, but they’re all very careful not to show you that information as body temperature.)

You might think, “Okay, but what if I just take my temperature with it anyway?” While there’s nothing stopping you from pointing it at your forehead today, that won’t tell you your body temperature, just the temperature of the surface of your forehead. Not the same thing! My non-contact infrared thermometer says I have a body temperature of 98.3 degrees Fahrenheit. But when I switch it to surface mode, I’m a cool 94.7 F in the same spot.

There are a couple ways to get FDA clearance (not approval) for Class II devices, and Google wouldn’t tell us which avenue it’s going for or when it filed for approval. De novo authorization — which Apple sought for the Apple Watch’s on-wrist EKG detection back in the day — is for devices that aren’t like anything else on the market and are “reasonably safe and effective.”

There is nothing particularly novel about a non-contact infrared thermometer, though. It’s possible Google has asked for 510k clearance, which means that the company submits a bunch of data about the thermometer, and if the FDA decides it’s functional, unlikely to cause harm, and substantially similar to other approved clinical infrared thermometers, it is cleared for sale. Without that clearance, Google can’t let the Pixel 8 Pro tell you your body temperature, even if it’s perfectly capable of doing so.

Hand holding a smartphone. On a black screen, a white semicircle displays “76.8 degrees F”
Photo by Allison Johnson / The Verge
The temperature app uses the temperature sensor to tell you the temperature of something. As you’d expect.

Your body temperature is a good indication of whether you have a fever, and a fever is a good indication of whether you’re sick. That is information that can influence what kind of medical care you receive. And since that’s medical data, as part of the FDA clearance procedure, Google also has to show that its data privacy practices comply with HIPAA. That’s probably why body temperature data will be saved to Fitbit instead of your Google account. Fitbit data is siloed, and Fitbit has the capacity to comply with HIPAA.

What’s not clear yet is why Google put a temperature sensor on the Pixel 8 Pro and is going to the trouble of requesting FDA clearance to use it for body temperature readings. We asked four different Google spokespeople, and all four responded (promptly!) with a variant on the following: “All we can share at this time is that we submitted an application to the FDA so you can separately use our Thermometer App to take your own temperature and then save it to Fitbit.”

The Verge’s resident wellness gadget and FDA clearance expert, Vee Song, speculates that data from an FDA-cleared body thermometer could be used for illness prediction and cycle tracking, which other companies have already done with wearable temperature sensors. Or it could just be laying groundwork for future medical tech plans. Maybe Google wants to sell a bunch of Pixels to hospital systems!

The whole situation is reminiscent of the skin temperature sensor on the Galaxy Watch 5 and 6. Samsung encourages you to use it as a contactless thermometer to check the temperature of household objects, and it is used to measure baseline skin temperature changes for sleep tracking and period tracking. But it explicitly won’t give you your body temperature. In both cases, it feels like the company added the sensor in order to track body temperature and is fishing around for other things to do with it that don’t require as much paperwork.

FDA clearance can take a while. The first Withings ScanWatch didn’t go on sale in the US for nearly two years while it awaited clearance for its EKG and blood oxygen features. That took 16 months. It’s worth noting that while the ScanWatch 2 has an infrared temperature sensor, Withings, like Samsung, is only using the data obliquely to avoid having to get FDA clearance. As far as I can tell, no smartwatch or phone has yet been cleared to offer body temperature data via infrared sensor, so who knows how long clearance will take for the Pixel 8 Pro.

In the meantime, at least your $1,000 phone has a cool party trick.

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