(A) Relationship between morning platelet count category and the occurrence of same-day grade 2 or higher bleeding. Pediatric patients had a higher incidence of bleeding at the same platelet count as their adult counterparts except at platelet counts ≤5 000/μL (P < .001). (B) Relationship between age and time to first bleed in HSCT patients among adult and pediatric patients. Pediatric patients (18 years of age) had a shorter time from day of HSCT to day of first bleed than adult patients (P < .001). Reprinted from Josephson et al⁶  with permission.