The takeaway I get from the following websites is that zero PSA does not even exist. Read about The definition of a "ZERO" PSA is discussed here: 1st go to https://www.healingwell.com/community/ 2nd enter ZERO PSA into the search field in the upper right corner and click Enter button 3rd click on discussion of What's the Definition of "Zero" or "Undetectable PSA" ?
Also read Changes in PSA During Advanced Prostate Cancer https://www.webmd.com/prostate-cancer/prostate-cancer-psa-levels In one paragraph it says "Your prostate makes PSA. So do most prostate cancer cells." Say whaaat? I thought PSA only came from healthy prostate cells. Geez, I feel like I'm in my first year of med school!