SETTING BOTH PARAMETERS OF THE INTERNAL QUALITY CONTROL CHART: A FLOOR-CEILING IMPRECISION CORRIDOR FOR CONTROL LIMITS AND EXTERNAL QUALITY ASSESSMENT FOR THE MEAN - A STUDY OF 24 CLINICAL CHEMISTRY ASSAYS. (2026). Vietnam Journal of Community Medicine, 67(CD14). https://doi.org/10.52163/yhc.v67iCD14.6489