Someone on this forum (with initial WBC around 200 000) asked a few months ago if people had any idea when their CML might have started to develop. I can't add anything about the progression from 100 000 to 200 000 but meant to chime in with my own data in case it was useful but then didn't get around to it. So here it is...
Seven months before my diagnosis I had:
WBC 19 000 (normal range 3500-12 000)
neutrophils 11.56 (normal range 1.5-8)
basophils 1.96 (normal range 0-0.15)
monophils 1.96 (0-0.9)
The form clearly stated "This patient needs to be tested for CML" but unfortunately none of my doctors picked this up.
Seven months later when I was finally diagnosed it was:
WBC 89 400
However I also noticed that one and a half years before my diagnosis, even though my WBC was normal 7600, my basophils were 0.4 (normal 0.0-0.15) so I believe my CML process had started by then.
In fact it could have started even earlier because for ten years before diagnosis my basophils were between 0.03-0.07 and then at precisely two years before diagnosis they were right at the top of the upper band of normal.
So... 2 years for me I think.
One day, if we don't blow ourselves up first, we might see the advent of wearable technology that will detect these minor upward trends very early on. People could then get tested and then put on highly targeted drugs that knock the CML out in a week before it properly takes hold.
(*It was when I discovered that my two doctors had failed to notice the "this patient should be tested for CML" bit on the pathology results form that I decided to request back copies of my blood tests for the previous ten years and I have kept track of them all myself from that point on.)