I was dx with CML twelve years ago and have been on Gleevec for about ten years. I spent the first nine years on Gleevec as PCRU, but in January, I got a "positive" result on my quant BCR/ABL1, major test. The report stated: "fusion transcripts detected, but below the limits of quantification for assay...so BCR/ABL1 to ABL ratio cannot be calculated."
My next two PCR tests (all with the same lab) returned to PCRU.
However, my most recent September test again returned a positive result, this time the lab calls it a "weak positive", which may just be a terminology change at the lab. The result again mentions the result being below the limits of the test, so no ratio is calculable. But the report now adds "The result on the International Scale is <0.0069%".
I am wondering about that <0.0069%. If my previous tests were 0.000 PCRU, how does a lab come up with a bcr/abl fusion that's detectable but below their quant limit, and still report the <0.0069%? What is the pathologist seeing?
Maybe it's also worth noting that my January test was done with a 1 in 100,000 detection limit, but the Sept test done with a 1 in 125,000 limit.
Of course, I am trying to figure out what the result means regarding my disease. I went nine years PCRU and suddenly start jumping in and out of weak positives. Does this indicate resistance to Gleevec? Or is it a product of more increased sensitivity in the PCR testing?
What causes the jumping around, and does the jumping around affect my standing on the 'relapse prediction' chart for patients on Gleevec? (The one that says if you've been in PCRU for x many years, then your chance of relapse is y%)
I'd be grateful for any insight.