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10 Replies Latest reply: May 5, 2012 5:40 PM by CDW RSS

Change in PCR Test Result  - Different Lab, Different Country

CDW Registered Users
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Hello All,

 

it's a while since i last posted, mainly because of my move from the US to the UK and the subsequent adjustment to the NHS (but that's a different story). I have a question which i'd appreciate some input on, particularly from Trey as i think he wrote an article covering the issue:

 

http://www.cancernetwork.com/display/article/10165/1570782

 

so i achieved a PCR-U i the US after about 8 months on tasigna and it stayed there all the way through to a test on 17 Jan 12 - results came back PCR-U. I moved to the UK and had a PCR test on 2 Feb 12 - I only just got those results (that's the NHS for you) and they said BCR-ABL 0.17%. Despite my analytic mind telling me there has to be an explanation for this one can't help but think about this - worrying achieves nothing but that's easier said than done as many of us know.

 

The factors I need to consider are: the difference between the scale my US onc/lab was using and the sensitivity of that lab, the sensitivity of the new lab in the UK and the scale being considered there.

 

I fully expected there would be a change between labs and was anticipating a rise, but i fail to see how the results could have leaped from ~0.00% to 0.17%? I am aware it is only 2 data points and single data points don't mean much.  The rest of my CBC was fine WBC ~6k, no clinical signs and the results from this week's PCR test will be available to me mid-May (I have to call for them, not expect the onc's office to provide them to me as i found out). So while I wait for the results that we can establish a trend from, I would apprecite any suggestions of where i might be interpreting things incorrectly. Similarly, any pertinent questions for my onc on our next appointment would also be welcomed as this completely sideswiped me and dumped my inquisitive and critical mind into the trash can :-)

 

I hope everyone is as well as can be.

 

Chris

  • Re: Change in PCR Test Result  - Different Lab, Different Country
    valiantchong Registered Users
    Currently Being Moderated

    Hi,


    I think there are 4 points to consider, that may affect your results as below:

    1) if your report in US and UK has reference to the IS (international scale). The IS standard is established thru a reference base sample % of BCR-ABL that are to correlate with a standard lab.

    2) The sensitivity of the test, normaly a standard lab is sensitive to detect -4.5 log meaning 1 BCR-ABL cell to around 15K-25K samples. some lab are sensitive to about 100K that will be -5 log.

    3) Is your blood sample kept overnight or a few days before the testing start, this will degrade the blood sample and will coz the result less sensitive.

    4) Or there is an error in the testing.

     

    If you have any chances you could ask your doctor what he thinks and share with us with the knowledge....

  • Re: Change in PCR Test Result  - Different Lab, Different Country
    Trey Registered Users
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    Although this does not show a loss of MMR (rounding) it would not be expected to see such a difference in numbers.  I don't think the change in labs would be that significant (minimum 1 log difference, maybe even 2 or more).  You would not see any CBC differences at these low levels.  You are not in any peril, so wait for the PCR results for the sample that was just drawn.

  • Re: Change in PCR Test Result  - Different Lab, Different Country
    CDW Registered Users
    Currently Being Moderated

    Thanks Trey and Mr Chong. The sums simply don't add up and i have a sneaking suspicion we're comparing apples and oranges between one measurement and another. I appreciate the welcome words; as you can imagine it's a hell of a shock to go from believing you're in CMR to being questionably in MMR.

     

    We'll wait and see what the next set of results bring and i'll post an update.

     

    thanks

     

    Chris

    • Re: Change in PCR Test Result  - Different Lab, Different Country
      CML_in_ATL Registered Users
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      Hey Chris,

       

      I hope the UK is treating you well.  I have been agonizing over PCR testing sensitivity the past couple of weeks, and the bottom line is that it can fluctuate at those low levels, and my engineering mind also thinks that it is apples vs. oranges.  How sensitive was the US lab, and was your testing done on site, or was it shipped out?

       

      Hopefully you are running better than I am right now, cause I have had a foot problem for the past few months that is hobbling me a bit.  I even asked the hematologist today if it could be related to CML or the TKI, and he looked at me like I was crazy and told me to listen to the sports medicine people that I have been seeing.

       

      Stay healthy and enjoy the summer...I've done quite a bit of travel to your neck of the woods in the summer and really enjoy it...I especially enjoyed visits to the Hidden Brewery. :)

      • Re: Change in PCR Test Result  - Different Lab, Different Country
        CDW Registered Users
        Currently Being Moderated

        Hi Dan,

         

        UK has been good in parts and less fun in others - the weather here is particularly dreadful, we've struggled to break 55F all year and sunshine is nothing but a distant memory. Sorry to hear about your foot. As you know, whenever you have any other issues you always question yourself as to whether it's CML related; chances are it's not and even if it was what would you want to change about your treatment regime considering where you are right now?

         

        As for test results, i am convinced there is a method related explanation for this. I fail to see how i could have gone from >0.000 to ~0.17% in the space of two weeks.  So fingers crossed for the results in 1.5 weeks and i'll let you know.

         

        Take care

         

        Chris

        • Re: Change in PCR Test Result  - Different Lab, Different Country
          PhilB Registered Users
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          With the good old NHS you also have to factor in the possibility that they sent you someone else's results entirely!

           

          So what brings you to this side of the pond?

          • Re: Change in PCR Test Result  - Different Lab, Different Country
            CDW Registered Users
            Currently Being Moderated

            Hi Phil,

             

            I'm British but worked in the US for 4 years, which is where i was diagnosed 18 months ago. Just moved to Bristol in the last few months and have been struggling with the adjustment back to UK life. Quite frankly with my wife and mother in law being from the US, the UK doesn't feel like home to me any more. The NHS experience has been an eye opener, especially compared to the level of attention and efficiency i experienced in my previous (US) onc's office. The prospect of it being someone else's results or an erroneous result has certainly crossed my mind; however I am also acutely aware I might never have achieved CMR in the US and was in a false sense of security if the US tests were inadequate; however, on the balance of probability i struggle to see how multiple (3+) US PCR tests could be so wrong. Anyways, it's all hypothetical until i get the next UK data point on 15 May and can form a better opinion from there.  

             

            Pin, thanks for the kind words and i will certainly give an update on the curious goings-on in my life. There is seldom a dull moment in my life - not necessarily for the right reasons :-)

             

            Chris

        • Re: Change in PCR Test Result  - Different Lab, Different Country
          Pin Registered Users
          Currently Being Moderated

          Hey Chris, I'm so sorry that you've had this to shake up your world - we really do hang on to these tests so much and they mean so much to us that when something like this happens you just question everything. I imagine that time is on your side though if you reached PCRU in 8 months, whatever the result of the next test is. Let us know how you go - it's not often that we hear of this sort of thing happening so it is very interesting to all of us.

           

          Hey Dan - what's up with your foot? I've had really painful feet lately - when I run it feels like they are cramping in the arch, and just under my big toe joint is always sore...I know exactly what is causing mine - Gleevec! Don't let any doctor tell you otherwise Just kidding - seriously though, I hope it's not a bad injury.

          • Re: Change in PCR Test Result  - Different Lab, Different Country
            CML_in_ATL Registered Users
            Currently Being Moderated

            Chris - totally agree re: testing.  New country, new machine, etc etc.  Bummer about the weather!  I have spent many-a-sunny-day in Bristol enjoying delicious pints of bitter on the waterfront.  I've also done a good bit of running around the town ... I especially enjoy the hills in the city and running over the Clifton Suspension Bridge.  I'm sure you'll get some good weather soon.  And I will wear the Hidden Brewery shirt today in your honor!

             

            Pin - Sorry to hear about your feet, but glad to hear that you're able to run.  Yes, my left foot appears to be injured, but I'm going to need an MRI to really get an accurate diagnosis (and I'm putting it off cause I'm too cheap to pay for it, LOL).  It was originally diagnosed as peroneal tendonitis, but I'm getting pain in other parts of the foot a few hours after running that will persist for several days.  Some light swelling, etc.  I've done an Ibuprofen regimen and rested it a bit, but to no avail.  I'm going to try Naproxen for a few days and see if that makes more of an impact than Ibuprofen, then suck it up and max out my deductible for the MRI.  It's a shame cause I was close to getting my 10K time inside 44 minutes, even with low HGB/RBC levels ... I was really ecstatic about how fast I've been able to run as I've responded to treatment, but I guess my mid-40's body decided to break down at that speed.  I seriously did ask the doc if Gleevec could cause this, and he just gave me this blank "yeah Dan, whatever" stare.  Full disclosure = I'm a bit down about it , so hopefully we can figure it out and get me back on the road again - swimming and biking don't clear my mind the way a good run does.  Oh, and we still need to catch up on the abdomen pain!  I've been 'round and 'round about that one as well, and after discussing with the hematologist, we actually think it's anxiety-related and not a urology issue at all.  I'm trying a few things under his guidance to see if it helps.  So much to think about!

            • Re: Change in PCR Test Result  - Different Lab, Different Country
              CDW Registered Users
              Currently Being Moderated

              Dan,

               

              you may have inadvertently answered my question when i was reading your other post about conversations with your onc/hem. You mentioned your onc's lab didn't use the IS and also used their own baseline against which to establish PCR-U. I am now starting to question exactly what scale and baseline my US lab was/is using compared to the UK lab my samples were sent to. I was always happy to discuss my results as absolute numbers, i.e. the BCR-ABL was <0.000, therefore onc told me undetectable through the PCR test so all is good - remarkable similarities to your conversation, we never discussed log reductions as i was happy to trust what onc told me.  I'm certainly not being alarmist and I'm sure we'll all be ok; however, if nothing else this is raising my awareness of the test and it's making me want question the devil in the detail of exactly how the tests are conducted and against what baseline. I should have been more inquisitive from the off, but then again, as I mentioned to you before, i was happy to trust the onc and concentrate on the task of getting better.

               

              Chris

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