Good question. I may have misspoke. I'm remote from Mayo Phoenix so I get the PSA locally through Quest laboratory in my town. So my Mayo lab order that I printed and took to Quest simply ordered a PSA test. When I got the results, the Quest lab report showed a number of ".04" rather than something like "< .01". The lab report also said it was done with using the Siemens chemiluminescent method. Frankly, I didn't look further until your question to me. So maybe Quest in my town just did an ultra sensitive test, even though I don't believe that's what Mayo ordered. I don't know and I haven't followed up on it yet to see what Quest says. To further complicate it, my brother (a 30 PC survivor) continues to get routine PSA tests annually. He shared with me that his PSA has been undetectable (with the standard PSA test) for years, and that his last test at Quest showed .04 as well. Seem coincidental that we both ended up with a .04, so he speculated that .04 might be the bottom of sensitivity at Quest on their "standard" PSA test. Speculation aside, I do believe the PSA test Mayo ordered was just the standard PSA, but .04 was what was reported by Quest. I also agree it's contradictory so your question was valid and appropriate.