The Pulse Oximeter Worked. The Validation Didn't.

For about five years, a pulse oximeter clipped to a patient's finger was treated as settled technology. Cheap, everywhere, accurate enough. What the bench tests kept missing was that the device read low blood oxygen less reliably on patients with darker skin, and it did so without setting off any alarm. This week Philips won FDA clearance for a version built to close that gap. The engineering fix is real. The more useful thing for a founder is what the last five years say about validation.

Philips received a 510(k) clearance for a new reusable SpO₂ clip sensor, with optical refinements meant to hold signal quality across diverse patient populations, according to MedTech Dive. In its desaturation studies the company reported an accuracy root mean square of 1.6 percent, against the 3 percent the International Organization for Standardization recommends and the FDA recognizes. It also reported accuracy varying by less than half a percent between people with light and dark skin pigmentation. Medtronic cleared an updated Nellcor system on the same premise last month. Two of the largest device makers in the world are now competing on how well their oximeters work on everyone.

The device always worked. The validation didn't.

The hardware was never the problem. In 2021 the FDA warned about accuracy after a New England Journal of Medicine study found Black patients were three times more likely than white patients to have low blood oxygen the device missed. A 2022 JAMA study tied the same gap to delayed COVID-19 treatment eligibility for Black and Hispanic patients. The oximeters passed their tests and shipped anyway. They failed in the field, quietly, on a population the validation studies underweighted.

That is the part hard-tech and medical-device founders should sit with. A verification and validation protocol is not a lab formality. It is a statement about who you think your patient is. If your desaturation study runs on mostly light-skinned volunteers, you have not proven the device works. You have proven it works on the people you happened to test. The test population is a product decision, and it belongs to whoever owns what the product is, not to a contractor filling in a template. When I ran product for a surgical robot, the definition of the device and the safety story we had to prove were mine to hold. Hand that to a regulatory consultant and you have paid senior rates for a call that should have been made in the product seat, earlier and cheaper.

The market moved before the rule did.

Here is the part that makes this more than a fairness headline. The FDA's own updated guidance on pulse oximeter testing, the one calling for at least 150 participants and a real spread of skin tones, is still only a draft. It went out in early 2025 and has sat on the agency's under-construction list ever since. Yet Medtronic and Philips both cleared devices that beat that unfinished bar, and both said so plainly. They built to a standard that is not yet law.

I have been on the other side of that decision. When Galen went through its de novo, there was no regulation on the books for our device, so the FDA had to write one, and they asked us what it should say. We sent a paragraph. A day later our clearance came back with that paragraph as the regulation, word for word. We set the standard, and every later entrant has to match us. The lesson runs the same in both directions. A requirement that clearly reflects how your product gets used in the real world is not optional slack just because the agency has not finalized it. Build to it now, and you might get to shape what it becomes.

Dave Saunders is the founder of Base Reality Group and a Fractional CPO for hard-tech founders. He was a founder and operator at Galen Robotics, where the surgical-robotics platform earned FDA De Novo authorization in 2023, and he managed a 35-patent portfolio licensed from Johns Hopkins. He wrote Founders Who Finish and publishes The Build. More about Dave →