A 9-year-old boy is brought to the physician for a 2-day history of yellow eyes. He recently recovered from an upper respiratory tract viral infection. He did not receive any medications. Laboratory studies show:
Hemoglobin 10 g/dL
Total bilirubin 2 mg/dL
Direct antiglobulin test (+)
Blood smear Spherocytes
Which of the following is the most likely explanation for these findings?
