Quantikine elisa human free bdnf immunoassay

Blood samples were collected in the morning following an overnight fast. After resting in a supine position for at least 20 min, the samples were taken from the antecubital vein, and after immediate centrifugation, aliquots were stored at –70°C until analysis. BDNF concentrations were quantitatively measured by enzyme-linked immunosorbent assay (ELISA) using the Quantikine^® ELISA Human Free BDNF Immunoassay from R&D Systems (Minneapolis, MN, USA).

Plasma samples for BDNF analysis were obtained by a series of centrifugations of the whole blood. Plasma BDNF concentrations were determined in duplicate by enzyme-linked immunosorbent assay (ELISA) using a commercial kit (Quantikine^® ELISA Human Free BDNF Immunoassay, R&D Systems, Minneapolis, MN, USA), according to the manufacturer’s guidelines. After terminating the antibody-enzyme-substrate reaction, the optical density in each well was determined using an ELISA microplate reader set to 450 nm, with wavelength correction set to 570 nm. The BDNF plasma concentrations of the samples in each assayed plate were calculated based on the standard curve. The intra- and inter-assay coefficients of variations were minimal (less than 10%).

The Quantikine ELISA Human Free BDNF immunoassay (DBD00, R&D Systems, Abingdon OX14, UK) was used for the BDNF analysis according to the manufacturers' instructions. Serum was diluted 1 : 20 for the analyses. The intra- and interassay CV was 5.0% and 11.3%, respectively, and all samples were tested in doublet to minimize the interassay variability.