SAN FRANCISCO — In the last months of Steve Jobs’s life, the Apple co-founder fought cancer while managing diabetes.

Because he hated pricking his finger to draw blood, Mr. Jobs authorized an Apple research team to develop a noninvasive glucose reader with technology that could potentially be incorporated into a wristwatch, according to people familiar with the events, who asked not to be identified because they were not authorized to speak on behalf of the company.

It was one of many medical applications that Apple considered for the Apple Watch, which debuted in 2015. Yet because many of the health features proved unreliable or required too many compromises in the watch’s size or battery life, Apple ended up positioning the device for activity tracking and notifications instead.

Now, the Apple Watch is finding a medical purpose after all.

In September, Apple announced that the Apple Watch would no longer need to be tethered to a smartphone and would become more of a stand-alone device. Since then, a wave of device manufacturers have tapped into the watch’s new features like cellular connectivity to develop medical accessories — such as an electrocardiogram for monitoring heart activity — so people can manage chronic conditions straight from their wrist.