A 10-year-old girl is brought to the physician for a 1-month history of fatigue. Hemoglobin is 10 g/dL. MCV is 90 fL. Her father underwent a splenectomy and cholecystectomy when he was younger. Which of the following is most likely to be seen in this patient?
Decreased glucose-6-phosphate dehydrogenase activity
Decreased pyruvate kinase activity
Increased HbA2 and HbF
Increased erythrocyte osmotic fragility
Isolated elevation of aPTT