Fresh plasma was treated with freeze drying protective agent. Filling the plasma in vials, Germany Christ freeze dryer was used to lyophilize the plasma. The self-made materials were prepared, which should meet the requirements of Guidance on Evaluating the Homogeneity and Stability of Samples Used for Proficiency Testing (CNAS-GL03). The materials were deliveried into several hospitals for the determination of coagulation factor.

By screening tests and orthogonal experiments, the optimum freeze drying protective agent's formula was trehalose (1.5%), glycine (0.5%) and HEPES (0.2%). The average packing bottle precision value was 0.569 9 g (net weight), ranging from 0.564 6 g to 0.576 7 g, S was 0.003 5 g, and coefficient of variation (CV) was 0.61%. The average moisture of self-made lyophilized product was 1.22%, S was 0.197%, and CV was 16%. Homogeneity testing used 2 methods to evaluate (1) F test: F=0.06; (2) T test: P=0.053 so the homogeneity met the requirements of CNAS-GL03. The stability testing used |\begin{array}{c}\stackrel{\text{?}}{x}\end{array}-\begin{array}{c}\stackrel{\text{?}}{y}\end{array}|≤0.3σ, and the absolute value of difference was 0.07, which was < critical value 1.702, which met the CNAS-GL03 requirements. By using self-made lyophilized product in external quality control survey, the results of coagulation factor Ⅷ CV% were 21.3, 16.6 and 25.8(the results were similar to those of the National Center for Clinical Laboratory).

The self-made coagulation factor external quality control material can meet the requirements of external quality control scheme in local area.