Cryosupernatant plasma (CSP) is used in Canada for plasma exchange in thrombotic thrombocytopenic purpura. The refrigerated storage time for thawed CSP is limited in many areas to not more than 24 hours postthaw. Because large volumes of CSP are needed for plasma exchange, procedural postponement can lead to product wastage. To determine if CSP storage could be extended, we measured coagulation-related activities in CSP thawed and stored at 1 to 6°C for up to 5 days.

Study Design and Methods

Thirty-six CSP units were thawed, refrigerated, and sampled aseptically at 0, 24, 48, and 120 hours postthaw. Clotting factor activities (Factor [F]V, FVII, FVIII, and fibrinogen) and prothrombin time were measured using an automated coagulation analyzer, and von Willebrand factor (vWF) and ADAMTS13 activities using enzyme-linked immunosorbent assay.


Fibrinogen, FVIII, and vWF activities were unchanged from thaw values after 120 hours of storage; ADAMTS13, FV, and FVII activities were significantly lower than at thaw, but mean reductions were only −2.6, −7.7, and −12%, respectively. Losses were proportionately greater in the first 24 hours of refrigerated storage.


Extending the refrigerated storage of CSP from 1 to 5 days had little impact on product quality. The retention of more than 97% of initial mean ADAMTS13 activity after 5 days of refrigerated storage suggests that the shelf life of thawed refrigerated CSP could be extended without meaningful losses of its likely most important ingredients. CSP postthaw storage could be aligned to that of refrigerated thawed frozen plasma, currently available for transfusion in some jurisdictions for up to 5 days postthaw.