Probability of retransfusion after the first platelet transfusion. For patients with thrombocytopenia undergoing single or double doses of platelet transfusion the probability of retransfusion in arm A (single dose) and arm B group (double dose): panel A the probability of retransfusion decreased significantly in the arm B group (P = .001). The probability of retransfusion in patients with AL (panel B; 17 in arm A group; 12 in arm B) and AT (panel C; 31 in arm A group; 36 in arm B) was lower in the arm B than in the arm A group (P = .001 for AL, P = .003 for AT). Comparison involved use of the log-rank test.