The DiaSource ImmunoAssays 1,25(OH)₂ Vitamin D RIA is a competitive RIA assay, based on the Gold Standard extraction methodology.
The assay shows equal or superior sensitivity, precision and cross-reactivity profile to all other RIA assays in the market.
Only samples and controls, not the calibrators, are extracted with a mix of solvents and applied on cartridges to separate 1,25(OH)₂ Vitamin-D from other Vitamin-D metabolites.
After elution of samples and controls, the calibrators, samples and controls are incubated in coated tubes. A fixed amount of 125I labelled 1,25(OH)₂ Vitamin D competes with the 1,25(OH)₂ Vitamin D to be measured present in the sample or in the calibrator for a fixed amount of antibody sites immobilized on the wall of a polystyrene tube.
After an overnight incubation at room temperature, an aspiration step terminates the competition reaction. The tubes are then washed with washing solution and aspirated. A calibration curve is plotted and the 1,25(OH)₂ Vitamin D concentrations of the samples are determined by dose interpolation from the calibration curve.