ABSTRACT
This proficiency testing program is established to evaluate the pharmaceutical preparation analysis capacity of laboratories recommended by 18 countries and economies. It was authorized by Asia Pacific Laboratory Accreditation Cooperation (APLAC), and organized by Shanghai Institute for Food and Drug Control (SIFDC) and China National Accreditation Service for Conformity Assessment (CNAS). The 0.3sigma test is used to evaluate the homogeneity and stability of the proficiency testing sample. The results of the laboratories were assessed by Z-score. The robust average and the robust standard deviation of the participants' results were calculated as assigned value and standard deviation for performance assessment of hydrochlorothiazide and captopril using robust statistics. Thirty-three of 38 laboratories recommended by 18 countries and economies sent their results back. Twenty-four laboratories' results were observed as satisfactory. Five laboratories were identified as having reported at least one questionable result. Four laboratories were identified as having reported at least one unsatisfactory result.