Lab PSA undetacable standards

I had posted a while back about my forth psa test that moved from the "norm" of <.04 to .064. I know that this falls in the range of undeteable on some tests but was still worried. I had the chance to visit with a friend a couple of days ago that also has prostate cancer. He had his latest psa test a few days before our meeting over coffee. I explained my latest results to him at which point he showed me the results of his test. His psa had come back at <.064, the exact same number as mine. He explained that his doctor told him that a bunch of his patients had suddenly had their test numbers go up. The doctor called the lab and was told that they had installed new standards ( I have no idea what they would change) and that was the cause of the different results.


At first I was happy to hear a reason for the increase but am now wondering why a lab would use such a level for an undeteable reading. In the time that I have been visiting this forum I have seen lots of <.1 and <.04 listed as a standard for undeteable but not <.064. Does this sound strange to anyone but me? I am planning on calling the lab and hear first hand what they have to say. Keep in mind that I have been very nervous concerning psa numbers since the urologist told me that there was a good chance that the cancer had already spread before surgery.



Bob

Post Edited By Moderator (TC-LasVegas) : 2/11/2011 9:37:36 PM (GMT-7)

My Uro does not believe in ultrasensitive, so no discussion there.

My GP was getting consistent <0.01 from his lab, but then changed to another one for all their work - that one gives me a 0.02.

Variables include the machine and the type of test, probably other things on the lab side as well. Then we have the many variables of how and why PSA is created.

I suspect they did not change to a different "standard" in a sense of a nationally accepted medical definition, but a new test or hardware upgrade/change. They may have had issues with the test - who knows, reliability? and have accepted a higher undectectable floor in exchange for stability, reliability, cost, time?

If you are now being tested on a system that detects down to 0.064 from a test that detected down to 0.04, your PSA may not have changed at all. <0.04 is also <0.064.

Be happy with undetectable. Mine isn't.

Even those labs that define PSA <0.01 as their undetectable have a wide range of PSAs from samples taken within an hour of each other. My husbands PSA level was 0.01 from one lab and 0.03 with another. Both are well respected assays calibrated to the same WHO standard. There are people on this site (and outside this site that I know of) who have received <0.01 from each lab.

0.01 is a little scary and 0.03 is a lot more scary. The difference is not small. It's intruiging to know why there is so much difference between labs. However all we are trying to do by using to labs is tracking the trend while also verifying that whatever trend exists that both labs see the same trend.

Regards,

An

0.01 would be scary if you were expecting less

I agree with David that 0.01 is a really great result. The 0.03 from the other lab is of more concern, but at this still early stage, you can't read too much into the difference.

Ultra-sensitive tests do lead to PSA anxiety, which is why some don't like them. However if your PSA ever rises to a point where further treatment is needed, those ultra-sensitive results will show the trend earlier, even if they do jump up and down a bit.

David, you are right the 0.01 is not scary.
If we had consistant readings of 0.01 I would be pretty happy. It's the other lab that throws some concern into the mix. The 0.03 is a little scary especially as it has risen a little from 0.02. Of course this could be explained by round-off and daily variation.

I am still amazed at the difference between the two labs.

I hope and believe that the results will stay flat at the levels they are now. Negative margins, negative everything, no SVI, no EPE, no PNI, small volume cancer, <2% of the prostate. Paul will be doing the next test later this week. Results in the first week of March - we are going on our annual summer beach holiday up north for a week in the last week of this month with close friends - we will do our best to forget the upcoming test results.

Fingers crossed,
An