Definition of an optimal dose of platelets per kg body weight according to pretransfusion clinical status. For cut-off of doses ranging from 0.06 to 0.14 × 10¹¹ per kg body weight in adult patients, the percent of transfusions leading to a required platelet increment and transfusion interval was determined. (A) Required platelet increment and transfusion interval were arbitrarily defined as increment ≥ 50 × 10⁹/L and interval > 2 days in patients without clinical factors known to affect platelet consumption. (B) In patients with factors favoring platelet consumption, required platelet increment and interval were at ≥ 20 × 10⁹/L and 2 days, respectively.