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Table. 2. The assigned concentrations and uncertainties for human serum AFP concentrations in the BCCL Can-RMs
Variables Candidate reference materials
L1 L2 L3 L4 L5 L6
uchar (%) 1.2 5.9 3.9 6.8 2.8 5.8
ubb (%) 0.8 0.5 0.7 0.2 0.7 0.9
ults (%) 0.8 2.5 1.2 1.9 2.8 3.6
uWHO (%) 2.4 2.4 2.4 2.4 2.4 2.4
Relative standard uncertainty uc (%) 2.9 6.9 4.8 7.5 4.7 7.3
Relative expanded uncertainty, 2× uc (%) 5.9 13.7 9.7 14.9 9.4 14.6
Expanded uncertainty (µg/L) 0.7 3.7 8.1 18.9 21.9 97.3
Assigned value (µg/L) 12.0 27.0 84.2 126.0 232.2 666.4

Abbreviations: AFP, alpha-fetoprotein; BCCL, Beijing Center for Clinical Laboratories; Can-RM, candidate reference material; uchar, uncertainty of the measurement; ubb, uncertainty from homogeneity of the material; ults, uncertainty due to the long-term stability; uWHO, uncertainty of WHO standard materials; uc, combined standard uncertainty.

Ann Lab Med 2024;44:507~517 https://doi.org/10.3343/alm.2023.0447

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