Thị Thanh Phương, N. et al. 2026. SUMMARY MONITORING SIX SIGMA AND QGI IN THE EVALUATION AND FOLLOW-UP OF QUALITY FOR SELECTED BIOCHEMICAL TESTS ON THE AU5800 ANALYZER SYSTEM. Journal of Health and Aging. 2, 8 (Jun. 2026), 141–146. DOI:https://doi.org/10.63947/bvtn.v2i8.20.