Need input PSA 0.1

Prat:

Actually, PSA degrades in a blood sample.
I think they have to run the test pretty quickly.

So, a 25 reading becomes a 2.5 reading in 5 days.

Maybe someone else can confirm this.

I remember once a lab ran my PSA at 1, 24 , 48, 72 hours and the PSA kept decreasing sharply. I can't remember why they did the repeated runs

Mel

Prat:

Not at all trying to get you nervous. That would be horrible.

I am just saying that I would not expect QD to get the same result on a retest of the same sample, days later

(for the reason I mentioned).

Mel

Medical Diagnostic Laboratories are by AACC (American Association of Clinical Chemistry) and CAP (College of American Pathologists) standards supposed to report patient laboratory results without a less than symbol if it is within the instrument's detectable range. If the result is 0.1, that means that the PSA is measured as 0.1 ng/mL. That is different than a reported PSA of < 0.1 ng/mL. That means that the PSA could be anything from 0.00 to 0.09 ng/mL. If the laboratory is arbitrarily dropping the less than symbol, or forgetting to add it to the report, that is sloppy work and should be investigated and corrected by the QC folks at the medical lab. At big labs like Quest and LabCorp, there are so many departmental layers, sub layers, sub-sub layers, etc. that it is difficult to find the right person to correct the problem. I used to be a laboratory inspector for CAP and would find more problems in megalabs than smaller ones. A primary problem is that the giant labs are for-profit, and go to great lengths to squeeze out a profit for shareholders by cutting corners.

Take care and hang in there.....Tim

As another person who makes his living doing and reporting low level laboratory values, if the instrument and method have a detection limit of 0.1, then any value on the printout that comes in below 0.1 (anything between 0.01 and 0.09) will report as <0.1. The computer that drives the printer SHOULD be programmed to insert the "<" automatically when required. Which is why it's ALWAYS a good idea to ask for a copy of your printout.

There is also rounding involved with readings that are above the detection limit. And it's not arbitrary. Each instrument and method have what is called a limit of precision. And this is a statistical measure of 'noise' if you will. So, (and I do not know if this is accurate) if the standard test reporting limit is to one decimal place, and the limit of precision is +/- 0.03, then it is assumed that multiple quality control retests of the exact sample at the exact time will give the same average value within a range of +/- 0.03, and values will report as rounded to the nearest 0.1.

Tim, your comment leads me to think... How does me go about finding a small lab and verifying their quality level, to do this important test for us.
My plan, after my bad experience, is in the future, to just have my Dr draw the blood and send it to his hospitals lab. Is there a better alternative?

Pratoman (and everyone else), the key to this whole house of cards is to do what you can to make sure that all of your samples are analyzed at the same lab. It can be a hospital lab, a dr. office instrument, or whatever. Sending them to Labcorp or Quest is a crapshoot because there is no guarantee of which lab it goes to.

The idea is that if the same lab does your work, then bias due to sending them to different labs at least is eliminated.

 

     Had my appointment with urologist yesterday for my recent 0.1 reading.   As I expected, he suggested do another test in 3 months. I am going to get the ultra-sensitive test this time.   I just have to find a lab that does this....

   This is a preety standard approach to a psa that shows up as 0.1 using the standard PSA test equipment.  He noted that being 7+ years out and a gleason 6 retest in 3 moths is reasonable...   Agree ????