Pretransfusion trigger platelet counts and dose for prophylactic platelet transfusions.

PURPOSE OF REVIEW: To assess critically both the blood platelet counts that prompt a platelet transfusion (i.e. trigger) in various clinical settings in patients with thrombocytopenia caused by marrow failure and the dose of platelets infused (i.e. number per each transfusion) for optimal hemostasis, feasibility, and safety.

RECENT FINDINGS: Definitive studies (e.g. well-designed, prospective, randomized clinical trials) are not available either historically or at present to support evidence-based decisions. Instead, retrospective reviews and anecdotal reports provide observational data to assist in best guess clinical practices.

SUMMARY: Reasonable clinical practice, until more definitive data become available, is to transfuse enough platelets per each transfusion to maintain the blood platelet count >10 x 10/L in stable nonbleeding patients, >20 x 10(9)/L in unstable nonbleeding patients, and >50 x 10(9)/L in bleeding patients or in those undergoing invasive procedures.