Blood cancers can overlap in their symptoms so until the bone marrow biopsy details are analyzed it can be difficult to define or give a diagnosis. Even then it can be challenging. And some of these conditions can take years to develop.

Even though your friend’s monocyte counts were up a few years go, that may not have been enough to indicate a future problem. Elevated monocytes may indicate conditions like inflammation, infection, blood disorders other health issues. In my case, I had a routine physical and a CBC with differential panel just about 6 months before I had any hit of my AML. Looking back on those records, knowing what I know now about blood work, there was absolutely nothing on that panel to indicate I had a potential firestorm waiting to blow up six months later.
Frankly, there is no point for your friend to wonder if something was missed previously. I know it’s human nature to do so, but it wouldn’t have changed anything anyway. This is his new starting point on a different path. I always thought about my odyssey as my ‘Indian Jone’s adventure…life sure hasn’t been boring after my AML/transplant journey but wow, what a ride!
Let me know how he’s doing along the way. ☺️