OBJECTIVES: I. Determine the frequency and prognostic significance of persistent abnormal cells with an aberrant phenotype detected by multidimensional flow cytometry (MDF) in bone marrow samples from children who have achieved clinical remission after receiving treatment for acute myeloid leukemia or myelodysplastic syndrome. II. Compare the frequency of persistent abnormal cells obtained by MDF with that of polymerase chain reaction (PCR), morphologic, and cytogenetic analyses of these patient samples. III. Determine the frequency and prognostic significance of persistent abnormal cells with a leukemia-specific molecular marker detected by PCR in samples from these patients.