Galibrated Automated Thrombin Generation in Frozen-Thawed Platelet-Rich Plasma to Detect

To enhance the pract ica l appl icabi l i ty of the cal ibrated automated thrombogram (CAT) we invest igated whether frozen-thawed platelet-rich plasma (ft-PRP) can be used to assess the funct ion of the prote in C inhib i tory path-way, whi le preserv ing the natura l phosphol ip id compo-s i t ion. Recalc i f ied f t-PRP t r iggered wi th 0.5 pM recombi-nant human t issue factor shows a median thrombin potent ia l o f 1,719 nM.min, against 1,576 nM. min for f resh PRP. To obta in-70 % inhib i t ion. 6.7 nM act ivated prote in C (APC) has to be added, instead of 25 nM in fresh PRP; so the relative APC resistance of PRP appears to depend upon the presence of intact platelets. Factor Vl l l. added to normal f t-PRP to obta in a concentrat ion of 3.3 U/ml, increases the thrombin potent ia l in the pres