Rheological analysis was carried out on stored platelets stored in PAS. (A, B) Cold-stored platelets in PAS have similar clot stiffness and crosslinking density to fresh platelets (fresh = 1.0, n=4). (C) Cold-stored platelets in autologous plasma form clots in FXIII-deficient plasma with higher stiffness than fresh platelets (n=4). ns, not significant (P >0.05); *, P<0.05. 4C, platelets stored at 4°C; AP, apheresis platelets; PAS, platelet additive solution; RCD, relative crosslinking density; RT, platelets stored at room temperature.