I've found the watch to be within a percent or two of both store bought and hospital based "finger tip" meters.
You get the occasional outliers from a bad reading but in general that's how I've experienced, and I've had nurses and doctors say that they are "good enough".
And yeah in my experience, anything less than 90-93% in a hospital and they will have you on high flow oxygen pretty quick. So 85% as a single bad reading is fine, but a sustained 85% on a watch means you probably want to head to a medical facility.
You get the occasional outliers from a bad reading but in general that's how I've experienced, and I've had nurses and doctors say that they are "good enough".
And yeah in my experience, anything less than 90-93% in a hospital and they will have you on high flow oxygen pretty quick. So 85% as a single bad reading is fine, but a sustained 85% on a watch means you probably want to head to a medical facility.