Patent ID: 7405084

Claim:
A method for detecting an analyte in a sample in a flow matrix by use of biospecific affinity reaction, which method comprises: i. allowing an analytically detectable reactant (Reactant*) and a sample comprising the analyte to migrate through flow channels in a flow matrix to a detection zone (DZ) located in the matrix, in which there is a firmly anchored biospecific affinity reactant (Capturer), and ii. capturing the Reactant* in the DZ in an amount related to the amount of analyte in the sample, wherein A) the Reactant* has labeled particles as an analytically detectable group, and B) the Capturer is anchored to the matrix by immobilized particles which exhibit hydrophilic groups on their surface, wherein the hydrophilic groups are hydroxy, carboxy, amino or sulphonate groups and wherein the particles anchoring the Capturer have a diameter smaller than a smallest inner dimension of the flow channels of the flow matrix and do not interfere with detection of Reactant* in the detection zone.