This Journal feature begins with a case vignette highlighting a common clinical problem. Evidence supporting various strategies is then presented, followed by a review of formal guidelines, when they exist. The article ends with the authors’ clinical recommendations. A 72-year-old woman who is receiving apixaban for atrial fibrillation but otherwise does not have a clinically significant medical history presents to the hospital with lower gastrointestinal bleeding. On admission, her hemoglobin level is 8.5 g per deciliter, platelet count 2000 per cubic millimeter, and white-cell count 5300 per cubic millimeter. She receives a transfusion of packed red cells and platelets that results in an increase in the hemoglobin level and a decrease in bleeding, but only a transient increase in the platelet count. The examination is unremarkable. A peripheral-blood smear shows no abnormalities other than thrombocytopenia; these findings are consistent with a diagnosis of immune thrombocytopenia. How should this case be managed?