Millions of Americans own an Apple Watch, which commands roughly a 50 percent share of the smartwatch market. Among its many features, the Apple Watch can take your pulse. It also contains hardware to measure your blood-oxygen levels, and it has been doing so since the watch was released—but the hardware is not operable by the watch’s wearer, who thus cannot obtain the results. Under current FDA regulation, the function is disabled. It’s another example of how federal regulation of the production and distribution of pharmaceuticals and medical devices in the United States is less focused on stopping viruses and other diseases than on blocking private-sector innovators from developing solutions that may not work or might have harmful side effects.

This matters in the Covid pandemic. On April 20, emergency-room doctor Richard Levitan described in the New York Times what he’d observed treating patients in Bellevue Hospital in New York. Levitan had seen many cases of “silent hypoxia,” unknown oxygen deprivation in which “patients without respiratory complaints had Covid pneumonia”—even those admitted to the hospital for non-Covid-related health concerns. By the time most patients made it to the hospital, they had “remarkably low oxygen saturations.” Levitan’s recommendation: “Widespread pulse oximetry screening [as] an early warning system.”

Pulse oximetry refers to the measuring of blood oxygenation noninvasively, by firing wavelengths of light—red and infrared—through the skin. Variations in absorption between the different wavelengths by arterial blood allow us to read oxygen saturation. That sounds high-tech, but it’s an old technology, first developed for earlobes in the 1930s; fingertip pulse oximeters were developed in Japan in the 1970s. The plethysmograph in the Apple Watch that measures pulse works essentially the same way.

Yet the Apple Watch currently on the market cannot make this feature available to the consumer. Relatively inexpensive pulse oximeters remain widely available—usually. Like other items, from toilet paper to surgical masks, they’re unlikely to be widely available in a pandemic, when everyone wants a device and public demand outpaces manufacturing and distribution capability. Delivery dates on Amazon are already backed up for weeks.

The reason why Apple Watches are not available to fill some of this gap traces to 1976—about one month after Steve Jobs, Steve Wozniak, and Ronald Wayne founded Apple—when Congress passed the Medical Device Regulation Act. The previous year, the Centers for Disease Control had released a study, subsequently published in the New England Journal of Medicine, linking pregnant women’s deaths to the Dalkon Shield intrauterine device (IUD). Senator Edward Kennedy pushed through the new law, which expanded FDA authority to regulate medical devices.

As is the norm in the modern administrative state, Congress left the details of regulation up to the agency, in this case the FDA, which classified “pulse oximeters” as Class II medical devices, deemed to pose “moderate” risk to people. The FDA decided not to exempt pulse oximeters from “premarket notification,” the requirement that a manufacturer submit a device for 90-day pre-review by the agency before introducing it to the market. The definition for pulse oximeter in the FDA’s regulation seems broad enough to encompass the Apple Watch device, were it operative: “An oximeter is a device used to transmit radiation at a known wavelength(s) through blood and to measure the blood oxygen saturation based on the amount of reflected or scattered radiation.”

Like other agencies, the FDA does not rely solely on its formal regulations but also issues “guidance documents” that aren’t subject to legal challenge but essentially tell private-sector companies what they can and cannot do. These documents are not technically binding, but most corporate general counsels would dissuade their firms from introducing a product that clashes with agency guidance. In 2013, the FDA released guidance “recommending” extensive testing protocols for pulse oximeters. When Apple released its new watch two years later, it decided not to risk a notice of noncompliance—nor to hold up a product certain to bring in a flood of new revenues—by running afoul of the FDA’s proposed process and premarket approval.

Some of Apple’s competitors have begun rolling out blood-oxygen monitor devices—such as Fitbit, which received FDA approval earlier this year. Samsung’s Galaxy phones possessed the capacity to read blood oxygen as well as pulse through its built-in Samsung Health app—until the most recent version, the S20, which suspended the function, likely due to regulatory and legal concerns. (I have an older version and have been using it to monitor my oxygen.) Apple itself has finally started to get FDA clearance for other heart-monitoring features, so approval for the blood-oxygen feature may be on the way, eventually.

Cheaper finger-readers normally available on drugstore shelves are generally deemed for “wellness” rather than “health,” and the companies making them typically are exempt from FDA rules because the devices use essentially the same technology developed in the early 1970s, before the Medical Device Regulation Act was passed. That’s a good thing, because they’re much cheaper than the FDA-approved products, and clinical studies have shown that they perform about as well.

The FDA’s reluctance to cede control is understandable. The agency always faces harsh public and congressional scrutiny over drugs and devices that fail or cause harm. No one wants to see the next Theranos. But delay in introducing devices tied to human health also costs lives—even in ordinary circumstances, and especially in a pandemic. The FDA’s misplaced focus on perfection over speed tragically bottlenecked U.S. testing for Covid-19. Even the availability of something as basic as ethyl-alcohol hand sanitizer has been stalled by FDA oversight.

Pulse oximetry isn’t as simple as ethyl alcohol production, but it’s a decades-old technology. A company like Apple, with enormous brand equity, is unlikely to release a product that it doesn’t believe will work. The benefits of letting wearers of Apple Watches utilize a function that already lies hidden inside the product would almost certainly exceed the costs. For now, Americans can’t—and they could suffer as a result.

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