Table 2.

Assessment of the bias of 25(OH)D₃ detected by LC-MS/MS using NIST certified SRM-972a

SRM-972a 25(OH)D3	Certified values by NIST		LC-MS/MS
	Target values (ng/mL)	Uncertainty	Detected values (ng/mL)	SD (n = 3)	Bias(%)
Level 1	28.80	1.10	28.43	0.61	−1.27
Level 2	18.10	0.40	18.63	0.34	2.94
Level 3	19.80	0.40	20.09	0.23	1.47
Level 4	28.40	0.90	29.77	0.26	1.25

SRM standard reference material, NIST National Institute of Standards & Technology