Already had surgery at UCSF and was being contacted with information about videos to watch online before my follow-up. Didn't answer at first, but they left a voice mail and I called back from the same phone and was automatically recognized by that number.
You will be provided with a website to visit. Safe thing to do in cases like that is do a web search on that website.
Followed all instructions, which didn't require any personal information besides my birthday and confirmation of my name (which they already had, in both the call and online), The video I was shown was directly related to my procedure.
If you are still not sure, you can probably avoid logging in and try calling your UC hospital instead. This call is just UC's way of saving time through automation.
When I called back recorded voice said they were having trouble retreiving medical records and to enter my phone number. Hung up and am reporting them.
Also got a call today. It is a scam. The voice said it is calling from the University of California health system, but if this were a real call it would have said UCSD Health System or UCLA health or some such. It wanted me to go to some website to view "health videos". I didn't even bother to and added it to my block list.
Ok, this is NOT a scam. I'm scheduled to have surgery very soon at UCLA. The other day I received an email from the surgery department to watch a video before my surgery day, which I haven't watched yet. This call was a reminder to watch the video. The UC health system has instructional patient video system called EMMI. Google it. I called the surgery coordinator just to verify that this is real and she confirmed it.