Disappearance Rates of Coagulation Factors: Transfusion Studies in Factor‐Deficient Patients

Data are presented describing the circulating levels of coagulation factors after transfusion of blood and plasma into patients with deficiencies of factors V, VII, VIII, IX, and X. The half‐disappearance times of the factors were as follows: V, 16 hours; VII, 4 hours initially and 22.6 hours subsequently; VIII, 10.5 to 11 hours; IX, 4 hours initially, 39.5 hours subsequently; X, two components, the slower being 35 hours. All of the factors had an initial rapid disappearance with half‐disappearance times of a few hours. For factors VII, IX, and X, a two‐component logarithmic decrease was found. It is emphasized that, if these coagulation factors are proteins, they have half‐disappearance times which are considerably shorter than those of most other plasma proteins. The therapeutic implication of this observation is discussed in relation to hemostatic levels and survival of the coagulation factors in banked blood.