Objective: To design the proficiency testing (PT) project (No. NIFDC-PT-183) for assays of bismuth potassium citrate capsules and organize to assess the proficiency of complexometric titration in laboratories, and provide some technical analyses and advices.
Methods: Two groups of samples with different concentration were prepared. The uniformity was evaluated with one-way analysis of variance and the stability was confirmed with t-test, whose results all conformed the requirements. The samples with three combinations were randomly distributed to 279 laboratories. The determination was performed according to the assays of bismuth potassium citrate capsules in Volume Ⅱ of the Chinese Pharmacopoeia 2015. The median value and normalized interquartile range (NIQR) of robust statistical analysis was adopted and Z-scores were used to evaluate the results from each of laboratories.
Results: Among 279 laboratories, 240 laboratories results were satisfactory, 23 were questionable, and the other 16 were unsatisfied. The satisfaction rate was 86.0%.
Conclusion: The overall capacity of national laboratories for assays of bismuth potassium citrate capsules is good while a portion of participants require further improvement.