What is Undetectable?

[jimbay]

Hey Guys, I got a couple of PSA results back post RP. One from Quest reading .02 and one from a clinic type environment (non-extra sensitive) reading .05. Quest says that it only goes to “less than .02”. First question: do you all think .02 = “.02 or less” or is it .02. My doctor looked at both results and said, “meh, that’s as good as I need to read it for undetectable for now”. So second question: is there value in truly plotting/getting the lower values? I did nerve sparing - could a little healthy prostate remnants cause spurious results?

[Tall_Allen]

When it is less than 0.02, it is usually reported as "<0.02" There is no known implication of readings <0.03 ng/ml.

[Hidden]

My psa tests come from two different oncology centers because I travel to md Anderson and live in Kansas. They have never been the same. Here in Kansas it is .02 texas it is 0.00. Has been that for last two tests. No clear answer when I ask why with either place. Both seem happy

[baw1955]

As I reported a couple days ago my Dr told me my PSA results (first since my RP in Oct 2018) were non-detectable based on less sensitive test method. I gave a blood sample this week to get results from the more sensitive PSA test. This time I will ask for a copy to verify how results are reported .... "<0.02" or "not detected".

[Jp2sea]

It is hard to say. It might be within error of zero. It really depends on the lab and measurement method. They probably report their error somewhere. I have seen different reporting methods, but that sounds poor (if just giving a number). As you know, we really want to know if within the detectable range with 95% confidence. I wish they would be clear this. Even then, there is a low chance of having a measurement out of their estimated error. I'd follow up with them.

[Hidden]

labs vary in how they report. A level that low is great and often reported as "undetectable" by some labs. Some labs do not offer the ultrasensitive PSA unless it is specifically requested. I think that is also the phenomenon that carlo8686 is seeing.

[Hidden]

My Sonora Quest undetected threshold is < 0.1.

[David1958]

I think this is all about splitting hairs at this point. 0.03 or 0.02 is as good as undetectable in my book. The doctor does not even want to see me unless it goes up to 0.20. That is an order of magnitude higher. It is useless to quibble about these small values.

[RonnyBaby]

I have been sitting at undetectable (<0.02) for over 8 months.

I am told that this is as good (low) as it gets.

y 'nadir' or lowest point my readings are going to get. My baseline after the

aggressive treatment phases.

Right now, I am a waitfull watcher.

No one knows what to expect next (Now that is reassuring, isn't it?).

I've had at least 6 readings at different times in at least 3 different labs.

Once I hit '0', they all came back the same, with one exception. That reading was 0.002.

The difference is in the number of digits and the accuracy of the instrument.

The PSA number/ target to watch is anything above 0.1.

0.1 is a threshold that is above a desired reference point that is NOT undetectable.

In some cases, less that 0.1 has been considered a cure - especially if you had radiation treatment only.

Another term to remember is the 'nadir' or LOWEST point the PSA drops to, after treatment.

The lower, the better.

If you never reach (below) 0.1, there is (was) some residual that could be the source

of future PSA rising levels.

However, my understanding is that some oncologists might allow a patient to reach a value as high as '10' PSA before an ADT cycle is re-triggered (assuming that there is ADT cycling going on).

I still have lots to learn ...... are there any other comments that might help us out ?