Abstract: ［Abstract］Objective〖HTSS〗To measure and analyze the detection performance of clinical biochemical items in 26 mutual recognition laboratories in Hebei province by using the Sigma value(σ), to understand their quality level, and to propose improvement plans.
〖HTH〗〖WTHZ〗Methods〖HTSS〗Inter-room comparison data of internal quality control(IQC) were collected from 26 laboratories in Hebei province, including alanine aminotransferase(ALT), aspartate aminotransferase(AST), Na+, K+, total cholesterol(TC) and triglyceride(TG) were used as total error allowance(TEa) to evaluate the quality status of clinical biochemical routine items.
〖HTH〗〖WTHZ〗Results〖HTSS〗Twenty-six laboratories with quality control L1 item performance(≥6σ) accounted for ALT 3.85%, AST 3.85%, Na+ 3.85%, K+ 23.08%, TC 19.23% and TG 19.23%, and laboratories with quality control L2 item performance(≥6σ) accounted for ALT 46.15%, AST 50.00%, Na+ 3.85%, K+ 26.92%, TC 3.85% and TG 7.69%. Laboratories with performance 3≤σ＜6 at L1 of quality control accounted for ALT 73.08%, AST 76.92%, Na+ 96.55% , K+ 77.05%, TC 73.08% and TG 77.05%. Labs with performance 3≤σ＜6 at L2 of quality control accounted for ALT 53.85%, AST 50.00%, Na+ 92.31%, K+ 73.08%, TC 69.23% and TG 77.05%. 
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗The quality level of 26 laboratories in Hebei province has excellent performance. 6σ provides a unified and simple evaluation criterion, which is more convenient and intuitive for IQC comparisons.

Key words: laboratories； &sigma, metric method, quality control