. Author manuscript; available in PMC: 2020 Apr 1.

Published in final edited form as: J Steroid Biochem Mol Biol. 2019 Jan 9;188:90–94. doi: 10.1016/j.jsbmb.2018.12.011

Table 1:

Certified and Reference Concentration Values for Vitamin D Metabolites in Serum: SRM 972 and SRM 972a

Certified Concentration Values
	SRM 972		SRM 972a
	ng/mL	nmol/L	ng/mL	nmol/L
Level 1
25-Hydroxyvitamin D₂	—	—	—	—
25-Hydroxyvitamin D₃	23.9 ±0.8	59.6 ±2.1	28.8 ± 1.10	71.8 ±2.7
3-epi-25-Hydroxyvitamin D₃	—	—	1.81 ± 0.10	4.5 ± 0.2
Level 2
25-Hydroxyvitamin D₂	1.71 ±0.08	4.14 ± 0.19	0.81 ±0.06	2.0 ±0.2
25-Hydroxyvitamin D₃	12.3 ± 0.6	30.8 ± 1.5	18.1 ±0.4	45.1 ±1.0
3-epi-25-Hydroxyvitamin D₃	—	—	1.28 ± 0.09	3.2 ± 0.2
Level 3
25-Hydroxyvitamin D₂	26.4 ±2.0	64.1 ±4.8	13.3 ±0.3	32.3 ±0.8
25-Hydroxyvitamin D₃	18.5 ±1.1	46.2 ±2.8	19.8 ±0.4	49.5 ± 1.1
3-epi-25-Hydroxyvitamin D₃	—	—	—	—
Level 4
25-Hydroxyvitamin D₂	2.40 ± 0.21	5.81 ± 0.52	—	—
25-Hydroxyvitamin D₃	33.0 ±0.8	82.3 ±2.0	29.4 ±0.9	73.4 ± 2.3
3-epi-25-Hydroxyvitamin D₃	37.7 ± 1.2	94.1 ± 2.9	26.0 ±2.2	64.8 ± 5.4
Reference Concentration Values
	SRM 972		SRM 972a
	ng/mL	nmol/L	ng/mL	nmol/L
Level 1
25-Hydroxyvitamin D₂	0.60 ±0.20	1.46 ±0.49	0.54 ±0.06	1.3 ± 0.2
25-Hydroxyvitamin D₃	—	—	—	—
3-epi-25-Hydroxyvitamin D₃	1.39 ± 0.04	3.46 ± 0.11	—	—
Level 3
25-Hydroxyvitamin D₂	—	—	—	—
25-Hydroxyvitamin D₃	—	—	—	—
3-epi-25-Hydroxyvitamin D₃	0.76 ±0.02	1.19 ± 0.06	1.17 ± 0.14	2.9 ± 0.4
Level 4
25-Hydroxyvitamin D₂	—	—	0.55 ± 0.10	1.3 ± 0.2
25-Hydroxyvitamin D₃	—	—	—	—
3-epi-25-Hydroxyvitamin D₃	1.06 ± 0.03	2.65 ± 0.06	—	—