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PCR 22 months. Now worried

Hello friends, I have received my latest PCR study carried out on 12/03/2020 the result is RM 4.0 PCR 0.0063 78,000 ABL copies, it was going down very well but this time it went from 0.0035 to 0.0063, should I be pre-cured? I really don't know what to expect ..... my doc told me to stay calm. What margin of error do these tests have?
From already thank you very much.

The margin of error is way, way above the differences in your tests. They are pretty much the same, and the next one might be down. 

You have gone from 3 in 100,000 cells to 6 in 100,000 cells. When it's put that way there's so little difference.


Thank you very much David, I know it is a long way and many times I let myself be carried away by my anxiety, I know that I am doing well and that the margin of error at that depth of response is a lot. But I came in a downward trend, to become a candidate for TFR as soon as possible, two steps forward and one step back, I think that is what it is also, I will do it one day, I am sure of it.

Thanks again, I really hope we all find ourselves well and promptly in TFR


I try to not worry when I have the ups - and also not celebrate the downs too much either. 

2 tests ago I was 0.001%, last one 0.08%. The pessimist says that’s an 800% increase. The optimist says it’s statistically well within the margin for error, and the realist says one was 1 in 100,000 assays, the other 8 in 100,000 so really both are very good results. 

Unless the differences are big, confirmed with a second test, and form a trend I don’t think it’s worth worrying about. 


Thanks again David, I understand from what I have read that the margin of error is 0.5, so the difference is very far from that.
but I have a question following my PCR path

DX 03/13/2018 58% (1s) in 193,000 copies of ABL
03/05/2018 Start treatment with nilotinib 600 per day
08/21/2018 0.028% (is) in 151,000 copies ABL (3 months of treatment) MMR
02/07/2019 0.022% (s) in 85,000 copies of ABL (9 months of treatment) MMR
06/06/2019 0.0098% (s) in 160,000 copies of ABL (13 months of treatment) MR 4.0
10/03/2019 0.0035 (is) in 165,000 copies of ABL (17 months of treatment) MR 4.0
03/12/2020 0.0063 in 78,300 copies ABL (22 months of treatment) MR 4.0

  I have noticed that the more ABL copies the less PCR, I do not understand the issue of ABL copies, can someone explain it to me?

Thank you so much

Hi Damian,

You'll find nearly everything you ever wanted to know about PCR tests in out booklet:

Quantitative Reverse Transcription Polymerase Chain Reaction: A primer for patients

To answer your specific question, the number of ABL copies is an indicator of the quality of the test. The bigger the number, the better. To detect down to MR5, 100,000 assays are needed. A test starts to become unreliable when below 10,000 copies or fewer.

It's a coincidence, not a cause, that your PCRs are lower when there are more ABL copies. 

For example, that is telling you that on 12/3/2020 you had 78,300 copies of ABL and about 493 (from 0.0063%) BCR-Abl. On 3/10/2019 you had 165,000 copies of ABL in your test, and about 577 BCR-Abl (from the 0.0035%). 


Thank you very much David, I understand that there is nothing to worry about, very easily it may be a variation of the study's own error, I saw that there are many laboratories that do not even report when it is so low, they consider it undetectable, I understand that after 0.00% very It can easily be a mistake.

Thank you for all the info