Composition of Fresh Frozen Plasma Compared to Normal Human Plasma
Direct Answer
Fresh frozen plasma contains essentially the same components as normal human plasma—all soluble coagulation factors, proteins, and inhibitors—with the critical difference being that labile factors V and VIII are preserved through rapid freezing to below -25°C. 1, 2
Complete Component Profile
Coagulation Factors Present in FFP
FFP provides the full complement of soluble coagulation factors including factors II, V, VII, VIII, IX, X, XI, and XII at concentrations of approximately 0.5–1.0 IU/mL for the labile factors V and VIII. 2
Fibrinogen content is present at approximately 2 g per four units of FFP (each unit containing 250-300 mL). 1, 2
Von Willebrand factor is maintained in FFP, though approximately 8-13% of units may have levels slightly below 0.50 IU/mL after standard processing. 2, 3
Coagulation Inhibitors and Regulatory Proteins
Anticoagulant proteins including protein C, protein S, and antithrombin III are preserved in FFP at levels above the lower limit of normal range in greater than 95% of units. 2, 3
Fibrinolytic components including α₂-antiplasmin are maintained, though plasmin inhibitor activity may be reduced by up to 76% in solvent/detergent-treated plasma. 2, 4
Critical Preservation Requirements
Temperature-Sensitive Factors
Factors V and VIII are the most temperature-sensitive components, requiring rapid freezing to below -25°C to maintain their activity—this is the defining characteristic that distinguishes FFP from regular plasma. 2
Factor VIII decreases by 13% after 8 hours of whole blood storage at 4°C and by an additional 15-20% after 24 hours, making rapid processing essential for FFP production. 5
Factor V shows approximately 15% reduction when whole blood is stored for 18-24 hours before plasma separation, though final levels remain adequate for hemostasis. 3
Stable Components
Factors II, VII, IX, X, XI, and XII show no significant degradation over 24-hour whole blood storage periods at 4°C, demonstrating greater stability than the labile factors. 5, 3
Fibrinogen remains stable with less than 12% reduction even after extended storage, maintaining therapeutic levels in greater than 95% of units. 3
Processing Effects on Composition
Standard FFP Production
Leukodepletion and rapid freezing preserve all coagulation factors without significant loss, maintaining factor activities within normal ranges. 2, 3
Male-donor plasma is preferentially used in some countries (e.g., United Kingdom since 2003) to reduce TRALI risk, as anti-HNA and anti-HLA antibodies are more prevalent in multiparous women, but this does not alter the protein composition. 2
Solvent/Detergent Treatment Effects
S/D treatment reduces protein S activity by 35% and plasmin inhibitor by 76%, though all other clotting factors remain in normal range. 4
Factor VII may be partially activated during S/D treatment, though this does not result in marked increases of other markers of activated hemostasis. 4
Interindividual variation is significantly lower in S/D-treated plasma compared to single-donor units, providing more standardized factor levels. 4
Post-Thaw Stability
Factor VIII activity decreases markedly during 8-hour storage after thawing, while fibrinogen and factors V and VII remain stable. 4
Thawing temperature (37°C vs 56°C) does not significantly affect factor V (85% vs 80% activity) or factor VIII (86% vs 90% activity) levels, nor does it alter fibrinogen, PT, aPTT, or factors II, VII, IX, and XI. 6
Key Distinction from Normal Plasma
The fundamental difference is not in what FFP contains, but in how it is processed: FFP is rapidly frozen to preserve labile factors V and VIII that would otherwise degrade in liquid plasma stored at 4°C. 2 This preservation through freezing is what makes FFP suitable for replacing coagulation factors in bleeding patients, whereas regular plasma that has not been rapidly frozen would have inadequate levels of these critical labile factors. 1, 2