title: Stability of coagulation proteins in frozen plasma.
abstract: This study reports on the frozen stability of all commonly measured coagulation proteins in normal citrated plasma: activated partial thromboplastin time, prothrombin time (%), thrombin time and fibrinogen (Clauss); clotting assays for factors II, V, VII, VIII, IX, X, XI and XII; functional assays for protein C (clotting), protein S (clotting), antithrombin (chromogenic) and plasminogen (chromogenic); and immunological assays for von Willebrand factor and D-dimer. All these factors listed are stable for up to 3 months if frozen at -24 degrees C or lower. At -74 degrees C, all these factors (allowing for 10% variation) were stable for at least 18 months, most were stable for 24 months. The number of proteins showing > 5% variation over baseline after 6 months storage indicates that some decay does occur even at -74 degrees C. There was no clear advantage in snap freezing at -74 degrees C and then storing at -24 degrees C over both freezing and storing at -24 degrees C; therefore, the freezing process itself is not responsible for the loss of stability. The best stability, especially at -24 degrees C, was obtained when small samples (1 ml) were stored in screw-cap tubes with a minimum dead space. The decrease in stability of the coagulation proteins directly correlates with the effect of temperature and time.
authors.affiliation: Serbio (Diagnostica Stago), Gennevilliers, France.
authors.forename: B
authors.initials: B
authors.lastname: Woodhams
authors.forename: O
authors.initials: O
authors.lastname: Girardot
authors.forename: M J
authors.initials: MJ
authors.lastname: Blanco
authors.forename: G
authors.initials: G
authors.lastname: Colesse
authors.forename: Y
authors.initials: Y
authors.lastname: Gourmelin
mesh_terms: D001777:Blood Coagulation; D001798:Blood Proteins; D006801:Humans; D010949:Plasma; D013997:Time Factors
chemical_list: D001798:Blood Proteins