An 80-year-old man is seen for an annual physical examination. He complains of shortness of breath on exertion and is often tired. His stool is black. Laboratory data are: Hemoglobin: 8.2 g/dL Hematocrit: 30% White cell count: 4.2 × 109/L White cell differential: Neutrophils: 60% Lymphocytes: 31% Monocytes: 7% Eosinophils: 2% Basophils: 0% Red cell count: 4.0 × 1012/L RDW: 20% Platelet count: 400 × 109/

An 80-year-old man is seen for an annual physical examination. He complains of shortness of breath on exertion and is often tired. His stool is black. Laboratory data are: Hemoglobin: 8.2 g/dL Hematocrit: 30% White cell count: 4.2 × 109/L White cell differential: Neutrophils: 60% Lymphocytes: 31% Monocytes: 7% Eosinophils: 2% Basophils: 0% Red cell count: 4.0 × 1012/L RDW: 20% Platelet count: 400 × 109/