Table 2.

25(OH)D values in nmol/L by each immunoassay and LC-MS/MS before and 30 days after a single dosage of 200,000 IU vitamin D₂

	Before treatment (nmol/L)	After treatment (nmol/L)
Centaur	35.4 ± 6.2	43.9 ± 8.7†,‡
Elecsys	37.6 ± 11.8	46.7 ± 13.4†,‡
LC-MS/MS 25(OH)D2	0.6 ± 2.2§	15.6 ± 7.6‡
LC-MS/MS 25(OH)D3	37.8 ± 10.2	40.6 ± 12.7‡
LC-MS/MS total	38.3 ± 10.7	56.0 ± 14.7†,‡

^†p<0.05, comparing the three assays in the same before or after treatment group, using Friedman M test; ^‡p<0.05, comparing the corresponding before and after treatment value, using paired t test; ^§most 25(OH)D₂ levels before treatment were undetectable (<5.5 nmol/L), which we regarded as 0.