Short-time stability of markers of coagulation and fibrinolysis in frozen plasma

We studied the stability of three markers of coagulation (prothrombin fragment 1+2 (F1+2), thrombin-antithrombin III complexes (TAT), and soluble fibrin (SF)) in stored frozen plasma, in addition to one marker of fibrinolysis (total fibrinogen degradation products and fibrin degradation products (TDP)). All markers were measured using enzyme linked immunosorbent assays (ELISA). None of the markers changed significantly after initial freezing. F1+2 in plasma was stable following storage at -80 degrees C for 3 months. In plasma containing high SF levels stored at -80 degrees C, an insignificant time dependent trend towards decreasing plasma values was observed. TAT levels in plasma decreased significantly following 3 months at -80 degrees C. TDP levels in plasma showed some fluctuation when stored in freezer. Our results suggest that careful observation of the long time storage stability of protein components is demanded in clinical research.