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. Author manuscript; available in PMC: 2016 Jul 1.
Published in final edited form as: Anal Bioanal Chem. 2015 May 13;407(19):5615–5624. doi: 10.1007/s00216-015-8733-z

Table 4.

Trueness of the candidate reference measurement procedure for quantitation of 25(OH)D2 and 25(OH)D3 using NIST SRM materials with certified values

SRM
972a - Level 2 972a – Level 3 972a – Level 4 972 – Level 1 972 - Level 3
25(OH)D2
na 10 10 0 0 10
Target ± U,b nmol/L 2.0 ± 0.2 32.3 ± 0.8 0.54 ± 0.1 1.46 ± 0.49 64.1 ± 4.8
Meanc (95% CI), nmol/L 1.97 (1.94–2.00) 32.7 (32.5–32.9) __ __ 64.2 (63.3–65.1)
Truenessd (95% CI), % 98.5 (97.0–99.9) 101.4 (100.6–102.0) __ __ 101.1 (101.1–102.1)
25(OH)D3
na 10 10 3 5 10
Target ± U, nmol/L 45.1 ± 1.1 49.4 ± 1.1 28.7 ± 0.7 59.6 ± 2.1 46.2 ± 2.8
Meanb (95% CI), nmol/L 45.9 (45.4–46.3) 49.3 (48.5–50.1) 28.4 (28.4–28.5) 59.6 (58.0–61.3) 46.2 (45.5–46.9)
Truenessc (95% CI), % 101.7 (100.7–102.7) 99.8 (98.2–101.4) 99.1 (98.9–99.3) 100.4 (97.9–102.9) 100.0 (98.6–101.5)
a

number of independent analysis measurement series

b

The target value and the uncertainty listed in the NIST certificates of analysis [34,35]

c

Singlicate analysis of SRM using candidate RMP in each independent measurement series

d

Difference between candidate RMP and target concentration as a percentage of target concentration