Busulfan (Bu) is an alkylating agent commonly used in patients being prepared for hematopoietic stem cell transplantation (HSCT) for various types of hematologic malignancies such as acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) in addition to non-malignancies (thalassemia). In the clinical doses, Bu is considered as a potent cytotoxic drug which causes severe and prolonged myelosuppression.

The rapid quantification of estrone in serum can be useful to monitor estrogen levels and help explain abnormal menstrual cycles, symptoms of menopause, abnormal or heavy bleeding, infertility or any other hormonal alterations.