How accurate are the PSA Tests?

Thanks rockin2047. Information really helpful. I will review those sites to help me understand what to expect. Again thanks!

Just read the web sites what a great source of information.

I would recommend all who are wondering to read the two sites you provided.

Again also want to thank Mayo Clinic for providing this web site so us with prostrate cancer can share their experiences and information such as rockin2047 provided here.

Second that. There is too much talk about 0 PSA. Rather loose talk because they never define what 0 PSA means.

How ia 0 PSA defined?

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!

Thanks for sharing. I am just as confused. At one time, 0 PSA is defined as < 0.1. Because that is the level that the lab test can go. And also because it was believed that can only be achieved surgery. That is defined as 0 PSA. It is a cure. The others cannot. It is only under control. Then radio and hormone treatments can also get to that level. So their lab test developed 0.0 and even 0.00. The idea was only surgery can get that. The best radio and hormone can do is 0.0. But that seems to be also possible. So the old saying that only surgery can cure becomes open. Indeed, what is a cure? 0.1? 0.01? 0.001? Even surgery cannot always get to 0.001.
If you are in medical profession or school, may be you can offer some insight?

Laboratory tests are measurements. All measurements have error. The error determines the detection limit. There is no such thing as a zero PSA. A PSA of < 0.05 ng/mL does not mean PSA is there but it is < 0.05 ng/mL, nor does it mean there is no PSA there. It means that if there is PSA there, then it is below the sensitivity of this assay, but it does not mean zero. No test can get to a measurement of zero anything. It can only provide limits of detection.

A "cure" is when the cancerous tissue now resides in a jar. Surgery is the best bet for a cure, particularly if it turns out the pathologist can step-section the entire prostate and report that the cancer is confined to the prostate. But even that might not give you a "zero" PSA. The typical guy choosing surgery would like to retain most erectile function, which means following Walsh's pioneering "nerve sparing" prostatectomy. But, in sparing nerves, a small amount of prostate tissue might unavoidably be left behind. In such a case, you might expect some PSA to still be present in the system. Note also, pathologists are humans making judgements or measurements. In other words, there are a whole series of measurements and judgements from first suspicion to definitive treatment. This is the art and science of medicine.

One last comment. We are close to being able to say: "Well, the bad news is you have prostate cancer; the good news is you won't die of prostate cancer". [given your age, overall health, co-morbidities, etc,]. Such a statement might allay some of this angst in this discussion. When my urologist told me those very words, I assumed that he was looking at my Gleason 9's and saying that because he was doing an internal calculation on whether I would die of something else long before the cancer became clinically evident.

No problem with what you say. The problem is when people, some times even the professionals say things like PSA 0 or a cure, you are left wondering what they said is what you think they said?

Just a short comment.... Different methods of measuring PSA can be correlated, but they can't be directly compared. The ultrasensitive PSA's I get bottom at 0.006. My measurements have so far been between that and 0.016, but the most recent one was "undetectable." (I.e., =< 0.006)
My urologist, like yours, is looking for more than you've measured so far to take action. But if I measured 0.117, he'd tell me to take the next test in 3 months. As it is, he figures I can wait for six months. I'm still under 2 years, so I'm still developing a track record with uPSA's. It is surprising to me, though, that they vary a good bit--it's not just the sensitivity of the test, but also the uncertainty of what impacts it at such low levels. They're also looking in the blood, which is a pretty big puddle in which to circulate an antigen generated by relatively few cells once the prostate itself is removed (or almost all removed.)
I had some margins which were positive, and given my level of cancer in the prostate, the best I can figure is that I have 50-75% chance of recurrence, but later would be better than sooner, too, if you ask me.

Is it possible to have undetectable and declining PSA and develop bone mets?