I have had CML since June 2006 and my pcr results have always been expressed in terms of a ratio %, expressed by a single ratio. For example, the last result from the old lab was 0.00014. The new lab reports are b2a2 <0.001, b3a2 0.081, e1a2 <0.001. Are these results within acceptable margin of error?
switched labs, need help understanding differences
Posted 20 November 2012 - 09:41 PM
The latest PCR means that the b2a2 and e1a2 were not detected. This is just another way to say you never had these, or else they have become undetectable. Likely the former. So only b3a2 is detected, and likely that is the only breakpoint you ever had.
If your PCR reports from the previous lab was in percentage terms as you suggest, then it was .00014% . Most labs would not go to so many zeroes since the PCR is not that accurate. But if it was a ratio it was .014%
So if your old PCR was .00014% and the current one is .081%, that by itself does not mean anything. PCR results cannot be compared among various labs except possibly (and only roughly) by log reductions. Changing labs can significantly change the numerical result. You should do a few things:
1) Have all PCRs (former and current) converted to log reduction by your Onc or lab (maybe the new lab is International Standard, and if so, you would still be -3log/MMR)
2) If your current result is not an MMR response, you should have the PCR re-accomplished within a month or two. If MMR then you could wait longer.
3) Use the second PCR from the new lab to start a new trend line. Only results from the same lab can truly show a trend.
Posted 24 November 2012 - 08:10 PM
I'm sorry, upon review I mis-stated the results from the old lab. The old lab results were reported in number of copies per 100,000, so 0.00014 would be 14 copies in 100,000. 4 months prior was 0.00004, for 2 reports prior to that was 0.00001, and prior to that and beyond was 0.00000. The new lab reported 0.081 %. This report is the very first from the new lab. All other blood markers are normal except for a 13.7 hemoglobin (it's been that since 3 months on imatinib). There is no spleenomegaly or any of the other classic symptoms. So, are you advising that I request another test to establish a baseline and then retest in 3 months?
Posted 24 November 2012 - 11:48 PM
What is the log reduction equivalent for the .081% from the new lab? If it is International Standard, then it is -3log/MMR so no worries. Otherwise, maybe you should repeat the PCR in a month or so to see the new trend line.
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