[Precision control of a single step determination of blood coagulation factor VIII in the plasma].

The findings of a precision control are reported for a one-stage determination of the factor VIII activity in the plasma for a period of 6 months. The storage property of the reagents was achieved by storing them in fluid nitrogen. Coefficients of variation under 55 were achieved at controlling the normal range as well as the pathological one. Thus the precision of this method may be compared with that of clinicochemical examinations.