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Posted 7/19/2022 3:11 AM (GMT 0)
Since my salvage radiation which ended in January, all my PSA results have come back at <.01. These tests were all done using "Assay Method: Chemiluminescence using Siemens Vista analyzer."

I just got my latest result and I lost my < sign, but this test was done using the "Roche Elecsys total PSA method on the cobas e801 immunoassay analyzer."

It does say that "Results obtained with different assay methods or kits cannot be used interchangeably."

So is this new test more sensitive or something, and is it showing my PSA is actually detectable now?

I'm a bit freaked out so if anybody has any insight on this I would appreciate it!
Posted 7/19/2022 3:34 AM (GMT 0)
that may be as low as it goes. i'd look into it but i would be less concerned because it's a different assay and "Results obtained with different assay methods or kits cannot be used interchangeably."
Posted 7/19/2022 4:32 AM (GMT 0)
Hello, GeetarMan ~

You're uneasy and uncertain and unsettled ... understandably.

Best to settle the matter and reach out to your medical team & get some definitive insight.

I can send a question to my oncologist through my online patient portal.

He sends a reply in a timely manner.

I felt my latest PSA test was reported in a different way this past time, too. Perhaps a different assaying method?

Hope you can get some answers & rest easier!

With my best ~

CYCLONE ~ # Iowa State University
Posted 7/19/2022 4:34 AM (GMT 0)
Hi GeetarMan. I'd be happy to offer my two cents, but first, can we have the exact two readings as they appear on your labwork. For instance, <.01, would not have appeared, although <0.01 may have. And what was the actual Roche results you got: was it 0.01 or 0.010?

Be careful about results that have been transcribed into a patient portal by a doctor's office ordering the test: Sometimes someone drops a decimal place when copying the result from the lab into the portal when they shouldn't. (A < sign might also be mistakenly dropped.)

Knowing the exact results will help, if you have access to the actual lab paperwork.

When you have a result such as <0.01, you don't know just how much lower than 0.01 your actual value is. It could be, say, 0.009, which could easily rise to 0.010 on a repeat test even on the same sample! The Roche assay can test down to <0.006. Note that 0.010 is still a very low PSA! My own experience with the Roche assay is that one's PSA can fluctuate at these very low values. The assay itself has been shown to vary ± 0.002 even when the same known PSA concentration is repeatedly measured. Couple this with one's physiological fluctuations and sample prep, equipment calibration, etc., and you can see why small fluctuations in results shouldn't give rise to worry. An upward trend will reveal itself; fluctuations will come down as well as go up.

My rule of thumb is to get a ultrasensitive PSA test that reports at least one decimal place more than the decimal place you are watching. In general, IMO, men with high-grade or high-risk PCa should monitor their post-RP PSA with a three-decimal test, e.g., the Roche assay. (It appears, however, that some institutions use this assay but round the result to two decimal places).

For whatever reason, some men (like myself) seem to have low uPSA readings that fluctuate up and downmore than others.

Djin
Posted 7/19/2022 5:06 AM (GMT 0)
It is 0.01

The nurse always calls me to fill me in on the results and they will probably call me tomorrow.

But all my <.01 results are from a different method than the latest result I got today. So that seems a bit weird. I’ll ask why they used a different test method this time.
Posted 7/19/2022 4:32 PM (GMT 0)
FYI - I occasionally chat with another PCa fellow who is seen at U of MN (had RALP at Mayo) and he just asked me why his PSA test result was expressed differently from his PCa friend at the same lab. It was not the results so much but his friend was <0.01 ug/L recently and his was 0.01 ng/ml last week which are essentially the same thing only expressed differently. This leads me to believe that something is going on with equipment or reporting systems recently. There is no telling with these larger medical systems (M-Health) and what they may be doing at the lab level. I am sure he would be interested in what you find out.
Posted 7/19/2022 4:45 PM (GMT 0)
** This leads me to believe that something is going on with equipment or reporting systems recently. **

Maybe doctors are tired of getting phone calls and emails from patients asking what that "< thing" means on their PSA result. 😀
Posted 7/19/2022 6:19 PM (GMT 0)
Here is a spec sheet for the ROCHE uPSA assay done on a cobas e 801.

_____________________________________
"Detection Limits:

LoB 0.006 ng/mL, LoD 0.010 ng/mL, LoQ 0.014 ng/mL (cobas e 411 analyzer, cobas e 601, cobas e 602 module)

LoB 0.006 ng/mL, LoD 0.014 ng/mL, LoQ 0.030 ng/mL (cobas e 801 module)"
_____________________________________

For a period of time, labs using the Roche uPSA assay were told by the government they could report only the imit of quantitation (LoQ, <0.014) and not the limit of blank (LoB, <0.006); however, this has changed and the result you get if "nothing" is detected is again <0.006, as it was in the past.

For a fascinating, accessible explanation and illustration of the three terms see:

Limit of Blank, Limit of Detection and Limit of Quantitation (2008)

As I mentioned, it's best to look at the test results as they are reported by the laboratory, if available, rather than results transcribed in a non-laboratory portal.

If you had a Roche ultrasensitive psa test, the result you cited should be reported as 0.010 rather than 0.01, i.e., there should be three, not two, decimal places; this would be a transcription error. My uro's office portal once reported my uPSA result as 0.02, but changed it when I pointed out the Labcorp portal had the (correct) result, 0.020. When I first saw the 0.02, I was worried that a wrong (less sensitive) PSA test had been done.

Also keep in mind that there are two different calibration standards for PSA testing, WHO and Hybritech. I'm not sure which test uses which standard, but I believe there can be a 3-17% difference between the two when reading the same sample with (non-ultrasensitive) testing. See Comparison of Three Assays for Total and Free PSA Using Hybritech and WHO Calibrations for details. (I don't know if comparisons have been done for ultrasensitive testing, however.) This is yet another reason why you want to compare apples to apples and stick with the same test when possible.

Djin
Posted 7/20/2022 9:16 PM (GMT 0)
Djin - My guess is these large healthcare systems using MyChart may be controlling the reporting of values from the test equipment and they are not using Labcorp or Quest. From observing my test results coming through so quickly nowadays, there is probably no human involved in the reporting so transcription errors are not really possible. I also know that my wife and I use different health care systems, all on MyChart, and the acceptable ranges for a number of the same tests are different so each system must be able to customize results as they see fit. GeetarMan uses these systems as well I believe.
Posted 7/21/2022 1:23 AM (GMT 0)

Mumbo said...
Djin - My guess is these large healthcare systems using MyChart may be controlling the reporting of values from the test equipment and they are not using Labcorp or Quest. From observing my test results coming through so quickly nowadays, there is probably no human involved in the reporting so transcription errors are not really possible. I also know that my wife and I use different health care systems, all on MyChart, and the acceptable ranges for a number of the same tests are different so each system must be able to customize results as they see fit. GeetarMan uses these systems as well I believe.

Mumbo, of course, I don't know what may be happening and I don't know if Labcorp results go into MyChart, which is an EPIC product. I do know that Labcorp's uPSA always yields a result with three decimal places--any result with two decimal places is suspect for having been manipulated, either having the last decimal place lopped off, rounded, or incorrectly transcribed/reported in my book. If his test was indeed done by Labcorp, it should be available directly on the Labcorp portal, which would resolve any confusion. I would not trust a 2-decimal Labcorp uPSA result: if you look at every authentic Labcorp sample uPSA result online, you'll see 3 decimal places; the same goes for 5 years of my own Labcorp uPSA results.

On the other hand, my uro's office lab has Labcorp equipment that does a uPSA assay that goes down only to a lower limit of 0.05, i.e., it has two decimal places, but AFAIK, it is not done at Labcorp facilities and does not go down to 0.01. I'm pretty sure it isn't done on the analyzer that GeetarMan mentioned. I'm not ruling out that a hospital might have Labcorp equipment and testing that does have a lower detection limit of 0.01, but I'm skeptical.

Djin
Posted 7/21/2022 2:06 AM (GMT 0)
My results are posted on the MyBanner portal. When my PSA initially went undetectable it was reported as <0.020. I went to the portal and checked but it did not list which assay was being used. After about a year the assay was evidently changed. My PSA result now comes back as <0.01 (not <0.010). The portal did identify this assay as the Roche Elecsys.

I'm not sure if there is a practical difference in the real world between having one's PSA reported as <0.01 or as <0.010.

I actually would prefer to be on a PSA assay with a <0.1 undetectable threshold. I don't really need to know if I happen to have a returning PSA that floats around between 0.01 and 0.09. No need for the unnecessary anxiety. But, I guess I'm not so concerned that I would ask my oncologist to change assays.
Posted 7/21/2022 3:33 AM (GMT 0)
Matt - Agree 100%, those of us with surgery and RT under our belt only need <0.10 since it is really pass-fail now and grades don't matter much.
Djin - I appreciate your fondness for the third digit but as a retired engineer, I am pretty sure it is insignificant and provides little value other than bragging rights for the manufacturer.
Posted 7/21/2022 3:55 AM (GMT 0)

Mumbo said...
Matt - Agree 100%, those of us with surgery and RT under our belt only need <0.10 since it is really pass-fail now and grades don't matter much.
Djin - I appreciate your fondness for the third digit but as a retired engineer, I am pretty sure it is insignificant and provides little value other than bragging rights for the manufacturer.

I think I see what the problem is. The difference between a result of 0.01 and 0.010 is not bragging rights over the test used. Rather, it's about the reliability of the second decimal place. My PSA concerns after a G9 (4+5) final Gleason score were not the same as someone with a final G score of 6 (3+3). Knowing my post op PSA was <0.1 told me nothing about how close my PSA was to 0.1, the persistent PSA mark and the indicator that I would need RT after my surgery. To me there would be a big difference between a post op PSA of, say, 0.098 and 0.016. It's not the 8 or the 6 that would concern me, but rather the sensitivity of the test and the reliability of the 9 and the 1.

When I saw the (incorrectly transcribed) 0.02 in my uro's portal, I was not concerned about knowing what the third decimal place actually was; rather, I was worried that a test with a different sensitivity had been used and that the 2 could be a 3 or even a 4, i.e. that my PSA might have gone up considerably. There is uncertainty in the right-most digit. Knowing the results was actually done with the same uPSA test I had had, and was indeed 0.020 gave me the reassurance I wanted that it was likely my PSA had remained at about where it had been. It is a question about reliability: I am perfectly happy to round to 2 decimal places, but that is not the same as getting a result with 2 decimal places.

Of course this is of no concern for a G6 man happy that his PSA is remaining <0.1. My nadir was 0.007. Knowing my PSA is <0.1 doesn't help me monitor my trend. Much depends on your trigger PSA value for further treatment.

Men who get RT as their primary treatment can certainly use the <0.1 test designed for men with prostates: after all, they still have theirs and their PSA will not drop to the values where a uPSA test is that important. That is why I suggested that a post-RP man follow his PSA with a test that gives one decimal more than the decimal place they want to follow. A 3-decimal test lets you reliably round to 2 places. A post-RT guy looking to see if he is 2 over his nadir is obviously in a different monitoring position.

Djin

Post Edited (DjinTonic) : 7/20/2022 10:02:22 PM (GMT-7)

Posted 7/21/2022 4:44 AM (GMT 0)
As a retired mathematician and physicist (40 years) working with metrology, I can say Djin is correct in his analysis. The rightmost digit is considered the LSD (least significant digit). So if you want accuracy to 2 digits after the decimal, you have to measure as precisely as possible to 3 digits.
As mentioned, before my salvage radiation I was fixated on having 2 accurate digits to watch for trends (3 total digits after the decimal). After salvage RT, it is essentially a no-go test so 1 or 2 digit testing is ok.
As a side note, any technological civilization has to have an accurate, repeatable, and traceable to standard system of measurements (metrology). If you don't have this, you don't have a technological civilization and you are essentially cavemen. Don't get me started.
Posted 7/21/2022 5:05 AM (GMT 0)
gman,

Speaking as someone who lost my less than sign unambiguously about 18 months ago i know how you must be feeling.

For now the only thing you can do is monitor. The current SOC is wait for actionable intelligence which these days means a psma pet showing previously unseen hot spots. There is like a 30% chance of finding something once you hit a psa of like 0.30.

Which may take years.

Or it may take months.

Take comfort in the fact that there are some pretty smart people who are actively looking for a cure. For example search for amg509. There is a guy on healthunlocked in a phase 1 trial that went to 0 and has no signs of pca in his system.

Start looking for a Medical Oncologist that you feel comfortable with. A person you will trust your life with and someone you feel understands your intentions.

Once you have an MO get your prostate specimen tested for gene mutations. You should also get a germline genetic test (the kind where you spit in a tube). There are certain gene abnormalities that make your cancer susceptible to immunotherapy. They are rare but they do happen and treatment possibilities expand if you have certain deficiencies/variants.

So in 3 months time, check again. See how it goes.

Until then take active steps
- exercise
- eat right
- look for an MO you will trust.

We are here.
Posted 7/21/2022 5:25 AM (GMT 0)
No argument there. The “box” may be effectively measuring to 3 digits or more and displaying 2 digits because they know the reliability issue with the extra digits that the hardware measures. For example, I doubt a digital speedometer measures to the integer miles per hour. It gets more complex readings from its sensors and displays to the neared mph due to inherent inaccuracy of the “system” and no practical use for more precise numbers.

I was in the testing business years ago and results are always challenged when there is a problem. It is always amazing when computerized nuclear density testing machine are checked by digging a precise hole and weighing the soil removed to validate the testing. If there is a variance, the physical method always wins and the “precise” method is discarded which can end up with legal claims.

Sorry in advance to get you started.
Posted 7/28/2022 1:59 AM (GMT 0)
PSA was <0.006 in July 2021. PSA is <0.01 in July 2022. These results are from the same lab (CMB lab in Garden Grove, CA). Does it mean PSA has increased? or just because of different settings of the machine?

Post Edited (TN1932) : 7/27/2022 7:06:57 PM (GMT-7)

Posted 7/28/2022 2:18 AM (GMT 0)
The difference in the tests does not indicate any change in your PSA. You are still undetectable. The assay used has changed. The assay used in 2021 is very slightly more sensitive than the assay used in 2022. It doesn't really make any difference. You are still just fine. The most important thing is the "<", which you have.

Celebrate as you see fit 🙂
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