The autumn wind rattles the clinic windows as you sip lukewarm coffee, trying to catch up on charts. Your hematology clinic is overbooked, and the hum of the phlebotomy machines bleeds through the thin walls. Your next patient is Ethan, a 28-year-old software engineer, who looks exhausted and pale.

“I’ve been getting these strange bruises for a month, Doc,” he says, rolling up his jeans to show you scattered petechiae on his shins. “I figured I was just clumsy. But now I can barely walk up a flight of stairs without gasping. My girlfriend basically dragged me in here.” He manages a tired grin. “She’s usually right about these things.”

His vitals are stable. A stat complete blood count comes back and stops you mid-sip: severe pancytopenia, with hemoglobin 6.5 g/dL, an absolute neutrophil count of 0.3 x 10⁹/L, and platelets of 12 x 10⁹/L. The reticulocyte count is inappropriately low.