To all interested, - The widely recognized CLINICAL definition of "undetectable" has long been, and remains at most Institutions, LESS THAN 0.1 ng/ml, which is reported as <0.1 ng/ml on Laboratory Reports. In low or medium risk patients, and even in most high risk patients, stable or fluctuating PSA results below this level are rarely of clinical significance and are far more often the cause UNNECESSARY anxiety in many Cancer-free patients. For this reason, unless specifically requested by the patient and/or the ordering Physician, the Standard PSA test (1/10th ng sensitivity) is usually used for ROUTINE post-surgical monitoring at most "centers of excellence". (Mayo Clinic and Johns Hopkins are 2 with which I have personal knowledge)
There is nothing WRONG with using Hyper- or Ultra- sensitive assays, AS LONG AS, the patient is made aware of, and fully understands, the TRUE significance and the increase in non-biological variations that do occur at such extremely low levels of sensitivity. Certainly, Postings on Boards such as this indicate that this, often, is not the case and they are the cause of much needless anxiety in the vast majority of cases.
There MAY be significance in steadily increasing PSA results below this level, but it is highly unlikely that any corrective action will take place before such levels exceed the traditional 0.1 ng/ml "undetectable" threshold, unless there is other supporting clinical data available. - So rather than unnecessary worry, what is gained in most such cases? Below my signature is a copy of a Johns Hopkins article that directly addresses this question and I suggest that you may want to listen to the experts! - John@newPCa.org (aka) az4peaks
A Publication of the James Buchanan Brady Urological Institute Johns Hopkins Medical Institutions
Volume V, Winter 2000
The Downside of Ultra- Sensitive Tests You've had the radical prostatectomy, but deep down, you're
terrified that it didn't work. So here you are, a grown man, living in fear of a simple blood test, scared to death that the PSA- an enzyme made only by prostate cells, but all of your prostate cells are supposed to be gone -- will come back. Six months ago, the number was 0.01. This time, it was 0.02.
You have PSA anxiety. You are not alone.
This is the bane of the hypersensitive PSA test: Sometimes, there is such a thing as too much information. Daniel W Chan, Ph.D., is professor of pathology, oncology, urology and radiology, and Director of Clinical Chemistry at Hopkins. He is also an internationally recognized authority on biochemical tumor markers such as PSA, and on immunoassay tests such as the PSA test. This is some of what he has to say on the subject of PSA anxiety:
The only thing that really matters, he says, is: "At what PSA levels does the concentration indicate that the patient has had a recurrence of cancer?" For Chan, and the scientists and physicians at Hopkins, the number to take seriously is 0.2 nanograms/milliliter. "That's something we call biochemical recurrence. But even this doesn't mean that a man has symptoms yet. People need to understand that it might take months or even years before there is any clinical physical evidence."
On a technical level, in the laboratory, Chan trusts the sensitivity of assays down to 0. 1, or slightly less than that. "You cannot reliably detect such a small amount as 0.01," he explains. "From day to day, the results could vary -- it could be 0.03, or maybe even 0.05" -- and these "analytical" variations may not mean a thing. "It's important that we don't assume anything or take action on a very low level of PSA. In routine practice, because of these analytical variations from day to day, if it's less than 0. 1, we assume it's the same as nondetectable, or zero."