A person receives a diagnosis of leukemia when the bone marrow shows greater than or equal to 20% blasts (immature blood cells). If the sample on bone marrow biopsy is close to 20%, it may be considered borderline leukemia.
Myelodysplastic syndrome (MDS) occurs when a person's bone marrow produces cells that are dysfunctional. In one-third of people with MDS, acute myeloid leukemia develops.