This clinical trial uses a laboratory test called a high throughput sensitivity assay in planning treatment for patients with relapsed or refractory acute myeloid leukemia. The aim is to try to identify drugs that may be effective in killing leukemia cells for those patients who will not be cured with conventional chemotherapy. This assay will test multiple drugs simultaneously against a patient's own donated blood sample. The goal is to use this laboratory assay to best match a drug to a patient's disease.