Influence of Vitamin D Binding Protein on Accuracy of 25-Hydroxyvitamin D Measurement Using the ADVIA Centaur Vitamin D Total Assay

Table 2

Serum concentrations of 25(OH)D in healthy subjects, DBP-spiked samples from healthy subjects, pregnant women, and dialysis patients.

	Number of  samples	ADVIA Centaur Vitamin D Total assay	ADVIA Centaur Vitamin D Total assay	LC-MS/MS	LC-MS/MS
		Average ± SD (ng/mL)	Range (ng/mL)	Average ± SD (ng/mL)	Range (ng/mL)
Healthy not spiked (endogenous)	5	44.8 ± 20.1^a	24.0–75.0	44.6 ± 19.8	24.3–75.3
Healthy; (endogenous and endogenous + spiked)	30	43.7 ± 16.7^c,d	22.9–75.3	44.6 ± 18.0^e	24.0–75.0
Healthy (endogenous + spiked)	25	43.5 ± 16.7^b,d	22.9–75.3	44.6 ± 18.0^e	24.0–75.0
Pregnancy	36	25.3 ± 8.7	3.7–40.8	27.3 ± 9.6	4.0–44.9
Dialysis	40	29.0 ± 15.3	6.5–72.6	28.1 ± 14.8	6.0–67.0

To convert 25(OH)D concentrations to nanomoles per liter (nmol/L), multiply by 2.5.
^aP < 0.05 compared to the pregnancy group; ^bP < 0.01 compared to the dialysis group; ^cP < 0.001 compared to the dialysis group; ^dP < 0.0001 compared to the pregnancy group; ^eP < 0.001 compared to the pregnancy and dialysis groups.
DBP: vitamin D binding protein.