A novel bead-based fluorescence immunoassay for aldosterone

Aldosterone quantification helps evaluate the rennin-angiotensin-aldosterone system. The new bead-based mul-tiplex platform has not been applied in aldosterone detection to achieve simultaneous measurements of multiple hormones. A new sensitive competitive bead immunoassay based on Luminex technology for detecting aldoster-one in small sample volumes was developed using two-antibody coupled beads and biotinylated aldosterone as tracer in combination with an extraction step. The assay was validated in human and mouse samples and exhibited a linear working range from 10 to 1,000 pg/mL. The assay was reproducible and precise with intra-assay coeffi-cient of variations (CVs) from 6.0% to 11.2%, inter-assay CVs from 8.0% to 13.0% and good recovery [(90-110)%] and linearity [(89-107)%]. Excellent correlation was found between this new assay and the reference method (r = 0.96, P < 0.000,1). The successful establishment of this assay provides high possibility for carrying out bead-based multiplex assay measuring aldosterone and other parameters simultaneously in one 50 μL sample so that the efficiency can be improved and precious samples can be saved.