In the present kit, DIAsource has introduced a pre-treatment step in order to improve the clinical performance of the assay.
It is well established that the binding proteins interfere with the radioimmunoassay for SM-C.
The pre-treatment step used by DIAsource is the acid-ethanol procedure of Daughaday et al.
A fixed amount of 125I labelled SM-C competes with the SM-C to be measured present in the sample or in the calibrator for a fixed amount of antibody sites being immobilized to the wall of a polystyrene tube.
After an overnight incubation at 2-8°C, an aspiration step stops the competition reaction.
The tubes are then washed with 3 ml of wash solution and aspirated again.
A calibration curve is plotted and the SM-C concentrations of the samples are determined by dose interpolation from the calibration curve.