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Lab change and my BCR/ABL numbers went up


My oncologist said the new lab was more accurate, that's why my numbers went up.  I thought all labs were to the IS. Can anyone please explain this? Has anyone else experienced this?

Thank you



Hi Ray,

The IS system is not perfect, and not all labs are on the IS anyway and even those that are do not always report results on the IS. Mine, for example, is IS calibrated but reports local numbers so I need to run the conversion myself to get the IS figure.

Different PCR machines and processes can be more sensitive and produce more accurate results, based on more "assays" of the blood. 

What was your result at the previous lab, and at the new one? 



Lab Corp:   May 2018  B2A2 .0032 B3A2  0.1482   Sept 2018 B2A2  0.0032  B3A2  0.1123   Jan 2019  B2A2  0.1694

B3A2  0.1482  Apr 2019 B2A2  0.1304 B3A2  0.0844  Quest Labs  Jul 2019  BCR/ABL 0.431  Oct 2019 BCR/ABL 0.423 Jan 2020  BCR/ABL  0.749  Feb 2020 BCR/ABL  0.356  May 2020 BCR/ABL  0.250

Both Labs mark IS.  Thank you for the info regarding the difference in Labs.  That explains a lot.  My trend does seem to be coming down.  I've been walking daily (4-5 miles) and diet changes last 3 months. Could this be helping numbers to come down?   Aug 22, 2020 will be 4th year with CML.  Can the handling of the blood effect the PCR numbers.  Seemed to be a little confusion last time at blood draw with blood handling.  I tried to find correct protocol for blood handling on internet, no success.  Is PCR done under microscope or machine? I'm on Imatinib 400 daily.  Was thinking of possibly changing, but with numbers coming down might wait it out. Thank you


PCR is done on a machine and is a complex process, amplifying genetic code thousand and thousands of times. Newer machines employ different ways of doing it, so it’s not always directly comparable. Even the same machine in different labs will give different results due to blood processing and handling times and routines (indeed if you run the same test in the same lab twice it won’t be exactly the same either). 


David thank you for all the information.