Marrow or blood is examined under light microscopy , as well as flow cytometry , to diagnose the presence of leukemia , to differentiate AML from other types of leukemia ( e.g. acute lymphoblastic leukemia - ALL ) , and to classify the subtype of disease . A sample of marrow or blood is typically also tested for chromosomal abnormalities by routine cytogenetics or fluorescent in situ hybridization . Genetic studies may also be performed to look for specific mutations in genes such as FLT3 , nucleophosmin , and KIT , which may influence the outcome of the disease .