Post RALP PSA

Rob.Ski

So, on a whim, I got a PSA test ahead of yearly scheduled due in Feb. Normally at labcorp, my results were < 0.1. I did this one out of pocket at Quest and got 0.09. So, its still < 0.1 and I'm not sure if Quest normally reports value or < #? Guess my question would be how long to wait for a retest? I'm thinking a month and going back to labcorp.

Im concerned as this is right at the edge of detectable but, im not sure that my labcorp numbers werent similar all along.

swl1956

I've been using QUEST DIAGNOSTIC for my PSA tests for awhile. I believe they report value if greater than .04 I've had two results at <.04 and one at .04 I assume that's as low as they go.

rhobo23

I’m around 0.1 and my Uro doc is ordering these quarterly for me. I’ve read there is somewhat new “metastasis directed therapy” (MDT) that might be able to zap emerging Mets with radiation, so want to catch them early.

Clevelandguy

Hi,

I have a similar situation, for the last 4 yrs. I have been tested @ .05 with my hospital lab sensitive test. My hospital now switched over to Quest and the last two sensitive tests by Quest were @.1 even though they use a different test method. Scared the crap out of me but I think it’s the way Quest reports their testing. Had a talk with my GP and we will monitor it, as long as it stays constant I’m good and my GP agrees. Wish my hospital would not have changed labs but I bet they did it to save money. You might want to check the test method which should be on your lab results paperwork.

Dave 3+4

Rob.Ski

Got this from Quest test notes. I dont have labcorp results handy to compare:

The total PSA value from this assay system is standardized against the WHO standard. The test result will be approximately 20% lower when compared to the equimolar-standardized total PSA (Beckman Coulter). Comparison of serial PSA results should be interpreted with this fact in mind. This test was performed using the Siemens chemiluminescent method. Values obtained from different assay methods cannot be used interchangeably. PSA levels, regardless of value, should not be interpreted as absolute evidence of the presence or absence of disease.

Josephg

https://csn.cancer.org/discussion/comment/1725487#Comment_1725487

Well, that's a nice nothing burger from Quest.

Clevelandguy

Hi,

My old test was using the Access Hybritech PSA method and Quest is now using Siemens Chemiluminescent test method. Again as long as it stays at .1 I’m good, be concerned about increases. As far as your question on when to retest you can talk to your doctor about that but I will retest at my next yearly physical in late Summer.

Dave 3+4

Rob.Ski

Yup, that is what my nothingburger says, Siemens Chemiluminescent. Just need to find what Labcorp method was. Will have to wait until I have access to it.

Josephg

Interesting. I'm not sure that I'd like that.

My detection limit is 0.02, and in the past, when my PSA started to rise, my Oncologist was already planning out the next therapy options by the time that it reached 0.05, and started implementation by the time that it reached 0.11 on one occasion.

Rob.Ski

Is that ultra sensitive PSA detection limit? Ive seen posts where the difference in labcorp vs quest tripping the 0.1 limit would of been a difference in waiting a year where the person was able to see recurrence on a pmsa pet. Might not be the norm but, was for his case.

swl1956

This PSA stuff is giving me a headache! Lols! Just had a visit this morning with my GP for yearly physical. He says to me your PSA is zero. I say "no it's not, it's <.04" on the results page that he's looking at. He then says "we consider anything under .04 to be undetectable" So does this mean that's as low as Quest Diagnostics standard test is capable of detecting? None of my oncologists at Fox Chase have suggested any "ultra sensitive tests". In my case still having a prostate gland and while currently on ADT and after having completed 40 pelvic IMRT sessions, should I not be happy with a <.04 (undetectable)?

Last 4 tests were: <.04, .04, .06. and now <.04 The .06 reading was taken when I had a bad cold. Perhaps that would explain that rise. Docs tell me we'll watch the trend over time to determine nadir. I think it's more arbitrary for those of us not having our prostate removed?

swl1956

Just read where Labcorp ultrasensitive test can indicate as low as .003

Clevelandguy

https://csn.cancer.org/discussion/comment/1725510#Comment_1725510

Hi,

If you had NO Prostate at all I would be happy with .04 or .06. If you do some research anything usually below .1 is considered undetectable. Most sources say above .2 is where you should start being concerned even with your Prostate removed. I don’t know how much live tissue you still have since you do have your Prostate, but like your doctor said look for a stable trend over several readings. With a radiated Prostate .06 sounds fantastic in my non medical opinion.

Dave 3+4

swl1956

https://csn.cancer.org/discussion/comment/1725515#Comment_1725515

Thanks Dave! I hope you're right and hope yours and mine both stay in the undetectable range.