To evaluate the analytical performance of lipid detection items using the Six Sigma model and to develop individualized internal quality control (IQC) strategies and precise improvement measures.

The WS/T 403-2024 Analytical Quality Standards for Common Clinical Chemistry Tests served as the quality goal for lipid testing. Accuracy was assessed using data from the first 2024 external quality assessment of lipid provided by the Shaanxi Provincial Clinical Laboratory Center, while precision was evaluated based on IQC data from our laboratory. The sigma metric for each lipid parameter was calculated based on these three indices and plotted on a standardized sigma performance chart. Furthermore, individualized IQC strategies and improvement measures were formulated using the Westgard Sigma Rules flowchart and by analyzing the quality goal index.

The analytical performance of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein A (Apo-A) was rated as "Good", while that of apolipoprotein B (Apo-B) achieved "World Class" level. The recommended IQC strategy for TC, TG, HDL-C, LDL-C, and Apo-A were the 1_3s/2_2s/R_4s/4_1s multi-rule approach (N=4) with a batch length of 200 samples. For Apo-B, the recommended strategy was the 1_3s multi-rule (N=2) with a batch length of 1000 samples. Notably, precision deficiencies were observed in five lipid analytes, warranting prioritized improvement measures.

The Six Sigma model demonstrates significant utility in evaluating lipid analyte performance, designing IQC strategies, and implementing quality improvements, thereby enhancing laboratory testing capabilities.