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.
UCLA is not Spam! I wish the people commenting would be a little bit more educated before leaving erroneous comments. My son has surgery coming up at UCLA very soon. This is an information call. It's not spam.