Apple has a no-longer secret team working on monitoring blood sugar through Apple Watch. CNBC scooped the story, citing three unnamed sources who said Apple’s efforts were originally envisioned by Steve Jobs.

Apple has a small team of biomedical engineers working on the project in Palo Alto, and the effort has been underway for five years. Monitoring blood sugar levels through sensors—rather than blood tests—is considered the “holy grail” of life sciences. Lots of money has been thrown at the problem by a lot of companies, but no one has succeeded.

The reason being that this is how it’s currently done:

Apple Watch Diabetes Monitoring

Most diabetics check their glucose 4-5 times a day, and still have problems with low blood sugar because they react poorly to insulin. If Apple Watch monitored glucose levels continually, and gave alerts when it was getting dangerously low, it could save lives.

Detecting Glucose Levels Could Take Billions

Terrance Gregg, executive chairman of biomed company DexCom, told Reuters in 2014 that developing this technology could take, “several hundred million dollars or even a billion dollars.”

That’s just one well-informed exec’s opinion, but the reality is that no one has cracked it yet. If Apple did so, it would be a real game changer for millions of people afflicted with diabetes.

It would also be a game changer for Apple Watch and Apple itself. It would position both the device and the company as significant players in the life sciences industry. CNBC suggested it would make Apple Watch a must-have device for anyone with diabetes.

This is significant because Apple would require substantial levels of regulatory clearance to market a device with that kind of ability. Reporter Christina Farr said that Apple’s efforts were far enough along that, “Apple has been conducting feasibility trials at clinical sites across the Bay Area and has hired consultants to help it figure out the regulatory pathways.”

Ms. Farr’s reporting included that as of a year ago, some 30 people were working on this team. She also wrote that the team reported to Johny Srouji, Apple’s senior vice president of hardware technologies, and that it used to report to Michael D. Hillman. Mr. Hillman left Apple in late 2015 for Facebook’s Oculus VR goggles as head of hardware.

The CNBC article has a video interview with Ms. Farr relating to her coverage.

Apple R&D

Apple’s R&D budgets have skyrockets in recent years, even as the number of new shipping products has declined. Projects such as a (probably-no-longer-happening) car, augment reality, and blood sugar monitoring, not to mention anything that has actually remained secret, account for that increase. More importantly, all represent large scale, long-term efforts.

Jeff Butts contributed to this article.