The annual incidence of primary immune thrombopenia is 5/100,000 to 10/100,000. The number of patients with thrombopenia in China is increasing by over 100,000 every year.

Postoperative thrombopenia, on the other hand, has been shown by Krevans and Jackson 6 to be in large part a "washing-out" phenomenon secondary to the low platelet levels in stored blood-bank blood.