A 38-year-old woman presents to a physician’s office for progressive weakness and pallor over the last few weeks.

A 38-year-old woman presents to a physician’s office for progressive weakness and pallor over the last few weeks. She also complains of shortness of breath during her yoga class. She denies fever, cough, rhinorrhea, or changes in appetite or bowel and bladder habits. She is generally healthy except for an occasional migraine, relieved by acetaminophen. Last month, she began having more frequent migraine attacks and was started on prophylactic aspirin. Her pulse is 102/min, respirations are 18/min, and blood pressure is 130/84 mm Hg. Her blood pressures on previous visits were 110/76 mm Hg, 120/78 mm Hg, and 114/80 mm Hg. The physical examination is otherwise unremarkable. The stool for occult blood is positive. In addition to a low hemoglobin concentration, which other laboratory finding is expected in this patient? A. Decreased platelet count B. Prolonged activated partial thromboplastin time C. Elevated D-dimer D. Prolonged prothrombin time E. Prolonged bleeding time