Total 25(OH)D concentrations were measured by a chemiluminescence microparticle immunoassay method (CMIA), using an Architect 25-OH Vitamin D kit (5P02, Abbott Diagnosis, Chicago, IL, USA) and an i1000SR analyzer (Abbott Laboratories, Chicago, IL, USA). The cutoff value was determined as 20 ng/mL, according to a 2011 report on dietary reference intakes for vitamin D from the IOM [12 (link)].
ALB concentrations were measured by a colorimetric test study (Roche/Hitachi Cobas C, Mannheim, Germany), according to the procedure of the manufacturer.
DBP concentration in serum was measured according to the procedure using a quantikine human vitamin DBP monoclonal immunoassay kit (Catalogue number DVDBP0, R&D Systems, Minneapolis, MN, USA), according to the literature [40 (link)].
ALB concentrations were measured by a colorimetric test study (Roche/Hitachi Cobas C, Mannheim, Germany), according to the procedure of the manufacturer.
DBP concentration in serum was measured according to the procedure using a quantikine human vitamin DBP monoclonal immunoassay kit (Catalogue number DVDBP0, R&D Systems, Minneapolis, MN, USA), according to the literature [40 (link)].