Reading various peoples postings relating to their results, I am getting a little confused!
I see people quoting their pcr results as a percentage figure - i thought that % results related to cytogenetic testing/fish.
This expresses the % of leukaemic cells found in a bone marrow sample.
I understood that pcr results are not quoted as a percentage.
I wonder if someone could clarify.
Thanks
Paul
hi paul,
i understand that pcr is expressed as a ratio..... i am always given a percentage figure.
in my own case my last pcr result from a blood sample (not bma/bmb) shows the bcr/abl gene is currently at 0.153% positive
see anjana's explanation of pcr % ratios on the FAQ page.... here is an extract....
"....More useful are quantitative PCRs which give a number. To us laypeople, what exactly is this number? PCR tracks the BCR-ABL transcripts and the number that is churned out is a percentage ratio of leukaemic cells to total cells. In order to be sensitive and correct for degradation of RNA, a housekeeping gene is used as a control. And therefore, the PCR result is expressed as the percentage ratio of BCR-ABL (cancer marker gene)in leukaemic cells to housekeeping gene which is expressed in all cells. This ratio is necessary to cancel out errors in the PCR measurements and give a reliable marker of the disease status.
Nowadays, real-time quantitative PCRs are used in most of the top centers to track low-level disease. However, even in this low-level disease, there are sub-levels. Patients in CCR can have high PCR values or low PCR values. Therefore, the CML experts have come up with two stages of response in the molecular category. Major molecular response (MMR) is a 3 log reduction of the disease from diagnosis(1000-fold reduction) and complete molecular response is when there is no cancer marker present from the PCR tests.
Now, each lab will have their own PCR value depicting a 3 log reduction, 2 log reduction, 1 log reduction, 4 log reduction. Different housekeeping genes are used and there may be other factors that are different...."
sandy C ;o)
