Hey @modeler , I'm not an expert but have been reading here for a year or so...

I would say that going from .5 to .61 in a years time, not really a big deal. That .1 difference could be a host of things. A little dehydrated that day, recent activity etc.. I think the more important readings will be the next couple.

I see you're plotting annual readings, my guess is you are, or at least were, getting tested more frequently, plotting those numbers might be helpful.

If it was me, and I was getting tested annually at this point, for my own piece of mind, I might ask the doc for quarterly testing for 6 mos or a year to make sure it isn't the start of a trend, other than that I wouldn't be too concerned, but, everyone is different.

Also anecdotally, I had a conversation with a friend who goes to the same urology group I do who had radiation for treatment (unfortunately I've had RP and radiation) , his PSA is in your range and went up slightly like this. Our doc told him that over the years (he's been 6) some prostate cells can regen causing a very slight uptick in the PSA. It's the first time I had heard that and I'm no doctor but perhaps is something like this.

Hopefully it's nothing. Good Luck