Practical application of the sigma-metric run size nomogram for multistage bracketed statistical quality control analysis of eight enzymes.


Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, China. Electronic address: [Email]


BACKGROUND : A sigma-metric run size nomogram is used to recommend quality control (QC) strategies to reduce patient risks. Herein, we aimed to evaluate the sigma performance of 8 enzymes and apply multistage bracketed statistical QC (SQC).
METHODS : Sigma performance of alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatine kinase (CK), amylase (AMY), and lipase (LIP) were determined. Daily workload of each test was estimated and expected reporting QC intervals were designed. Per the nomogram, "start-up" and "monitor" QC rules were determined from sigma performance. SQC was finally applied, followed by quality improvement.
RESULTS : Sigma metrics were as follows: 5.26 (ALT), 4.80(AST), 5.25(GGT), 3.36(ALP), 4.71(LDH), 15.45(CK), 10.77(AMY), and 3.70 (LIP). "Start-up" rules were MR N2, MR N4, MR N2, MR N4, MR N4, 1:2.5 s N1, 1:3 s N1, and MR N4, and "monitor" QC rules were 1:2.5 s N1, 1:3 s N2, 1:2.5 s N1, MR N4, 1:3 s N2, 1:3 s N1, 1:3 s N1, MR N2 for 8 enzymes, respectively.
CONCLUSIONS : Multistage bracketed SQC is determined by sigma performance. Risk monitoring is significant during assaying to reduce patient risks and improve quality.


Multistage quality control,Nomogram,Quality improvement,Risk management,

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