How is active acute myeloid leukemia defined?

How is active AML defined? It's defined by the number of immature blast cells in the bone marrow. And the cutoff is 20%. I mentioned earlier myelodysplastic syndromes, which have less than 20% blasts. It's also a different disease in a way, but it can transform into AML. So definition is at least 20%, up to 100% of these immature cells that are defined by what they look like in a microscope. So they are round, they have a big nucleus, they have very little cytoplasm, and they are easily identifiable by a hematopathologist. So the definition is an accumulation, an increase in these cells. And that does not have to correlate to the blast number in the blood. Some patients have no circulating blasts. Some patients have 100,000 blasts per cubic millimeter. So that is not necessarily correlated. So the diagnosis of AML has to be established in the bone marrow.