@jeffmarc -- Thanks for weighing in and you raise a couple of good points. First, doubling checking what I wrote above and my lab reports, I misspoke above. My brothers psa and my psa 3 months ago was ".04", not ".004". Ugh; sorry about that. Second, I remember seeing that previous comment about "< .01" and I simply attributed it to human error because what I had consistently seen and heard were references to "< .1". But I probably should have inquired then rather than just assuming I knew what was going on. That said, here's what I do know for certain after double checking my lab reports: First, my latest psa report says "< .1" and that same psa report also explicitly states that "free psa is below detectable limits". Second, I just got off the tele visit with a staff Mayo urologist (unfortunately before I read your comment) and she clearly stated to me that "< .1" is what they're looking for. One thing I didn't clarify in my comment above is that neither my brother nor myself have been using the Mayo lab for psa testing (and in fact my brother isn't a Mayo patient at all). We both live remote and use the same local lab (Quest). At this point, I am sure of 2 points: First, what my latest psa test says and what I heard this morning from a staff Mayo urologist at my 6 month tele visit. I'm also reasonably sure "< .1" is what I heard 3 months ago from a different Mayo staff urologist at my 3 month checkup (especially since .04 is greater than .01 so if .01 was the threshold than I'm pretty sure the Mayo urologist would have discussed it further at my 3 month checkup). Sorry for the confusion and thanks again for questioning it.