title: The effect of repeated freezing and thawing on levels of vitamin K-dependent coagulation factors and fibrinogen in fresh frozen plasma.
abstract: BACKGROUND
  Fresh frozen plasma (FFP) is considered adequate for transfusion immediately after thawing or for up to 24 hours if kept at 1-6°C, and is currently used very often to replace deficient clotting factors. If factor levels in refrozen FFP are within normal limits, then this component can possibly be transfused, thus avoiding wastage of FFP.
  
  
  OBJECTIVE
  To study the fate of vitamin K-dependent coagulation factors (F II, F VII, F IX, F X) and fibrinogen activity levels in repeatedly (twice) frozen and thawed FFP.
  
  
  METHODS
  Two hundred FFP units comprising 50 units of each major blood group (A, B, AB, and O) were thawed at 37°C and 10-20 mL of FFP transferred to transfer bags with the help of a sterile connecting device (SCD). The FFP samples were taken into tubes (first sampling), and then the transfer bags were kept for 24 hours at 4°C. After 24 hours, repeat samples were taken in tubes from the transfer bag (second sampling), and then the bags were re-stored at < -18°C. One week later, the above procedure was repeated. Activity of coagulation factors and fibrinogen levels were measured by the automated coagulation analyzer.
  
  
  RESULTS
  The levels of F II, F VII, F IX, F X, and fibrinogen of all the 200 FFP units, at all four time points, were above the lower normal value, but well within the normal range.
  
  
  CONCLUSIONS
  The levels of F II, F VII, F IX, F X, and fibrinogen remain stable and adequate for transfusion in twice-thawed-and-refrozen FFP. This component can be safely used for transfusion as a source of vitamin K-dependent clotting factors and fibrinogen.
authors.affiliation: Department of Transfusion Medicine, AFMC, Pune, Maharashtra, India.
authors.forename: Joseph
authors.initials: J
authors.lastname: Philip
authors.forename: R S
authors.initials: RS
authors.lastname: Sarkar
authors.forename: Amardeep
authors.initials: A
authors.lastname: Pathak
keywords: Fresh frozen plasma; freezing and thawing; vitamin K-dependent clotting factors
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