Production and application of lyophilized urine samples used in microbiology external quality assessment programme in Vietnam

Introduction: The external quality assessment (EQA) for microbiological laboratories is one of the most commonly used services for quality assurance. In Vietnam, the majority of EQA samples are imported from foreign markets, involving high costs, complicated procedures and further making it difficult to ensure quality in terms of transport and management. The objective of this study was to develop a process for producing lyophilized urine samples containing pathogens (Escherichia coli and Enterococcus faecalis), evaluating the homogeneity and stability of the produced samples and the subsequent application of these samples in the launching trial program of the clinical microbiology program. Methods: The production process of was established according to ISO Guide 34:2009. The homogeneity and stability of production samples were evaluated according to the guidance of ISO 13528:2015. Produced samples were preserved at 2-8°C and assessed for stability after 2, 4, 6, 8, 10, and 12 weeks. Samples were subsequently utilized in the clinical microbiology EQA program, wherein they were sent to 26 laboratories located in several different regions across Vietnam. Results: The production process thus conceived comprised eight steps that ensured the homogeneity of the samples produced. Two sets of quality samples were produced and stability within12 weeks. Approximately 92% of the laboratories met the set target. Conclusions: The eight-step process to produce presumptive lyophilized urine samples has successfully developed. The produced samples reach the criteria for EQA samples and suitable to apply on clinical microbiology EQA scheme at national scale.