Which of the following is not true regarding post transfusion purpura?
a. It is most commonly due to anti HPA-1a antibodies
b. Usually develops after 3 weeks of blood transfusion
c. The treatment of choice is IVIg
d. Even HLA matched platelets are not useful
b. Usually develops after 3 weeks of blood transfusion
Post-transfusion purpura (PTP) typically develops within 5 to 10 days after a blood transfusion, not 3 weeks. It is most commonly caused by anti-HPA-1a antibodies, and the treatment of choice is intravenous immunoglobulin (IVIg). Even HLA-matched platelets are not effective in this condition.