 The two most commonly used classification <unk> for AML are the older French @-@ American @-@ British ( FAB ) system and the newer World Health Organization ( WHO ) system . According to the widely used WHO criteria , the diagnosis of AML is established by demonstrating involvement of more than 20 % of the blood and / or bone marrow by leukemic <unk> , except in the three best prognosis forms of AML with recurrent genetic abnormalities ( t ( 8 ; 21 ) , <unk> ( 16 ) , and t ( 15 ; 17 ) ) in which the presence of the genetic <unk> is diagnostic irrespective of blast percent . The French – American – British ( FAB ) classification is a bit more stringent , requiring a blast percentage of at least 30 % in bone marrow ( <unk> ) or peripheral blood ( <unk> ) for the diagnosis of AML . AML must be carefully differentiated from " <unk> " conditions such as myelodysplastic or myeloproliferative <unk> , which are treated differently . 
