Patent ID: 7892857

Claim:
A method of affinity assay for analytes that are affinity reactants comprising: introducing a high-molecular weight osmoticum solution into at least one aspiration chamber ( 1 ), wherein the aspiration chamber is bordered by an ultrafiltration membrane ( 5 ), thereby moving a liquid phase out of a filling chamber ( 2 ) through a flow path ( 3 ) into a measuring chamber ( 4 ), the measuring chamber being separated from the aspiration chamber by the ultrafiltration membrane, wherein the flow path connects the filling chamber to the measuring chamber, whereby due to a reaction of the analyte with another affinity reactant the liquid phase comprises labeled high molecular weight affinity reactants or reaction products of the analyte in analyte-dependent concentration, the labeled affinity reactants or reaction products being labeled with a functional group allowing a sensitive determination of their quantity; concentrating the high-molecular weight labeled affinity reactants or reaction products to be detected inside the measuring chamber; detecting the high-molecular weight labeled reactants or reaction products inside the measuring chamber; and flowing the liquid phase with low-molecular weight constituents through pores of the ultrafiltration membrane into the aspiration chamber.