Procedure and device for determining the concentrations of at least two ligands

A device for determining the concentrations of at least two ligands in a sample for analysis, with a metering chamber comprising at least one inlet opening and a drain opening, said metering chamber having a substrate on which a first receptor and a second receptor are immobilized on a first test site and a second test site, respectively, wherein said first receptor and said second receptor are bond-specific for a first ligand and a second ligand, respectively, and wherein a competitor is bond-specific for said second receptor, wherein a first sensor to capture a first metering signal relative to the concentration of the ligand bound to the first receptor and a second sensor are arranged on the first test site and the second test site, respectively, wherein the device comprises a mixing device for mixing the sample with the competitor that is bond-specific to the second receptor, which mixing device is connected to an infeed opening for the sample and a receiving space containing the competitor;

• that the mixing device comprises an outlet opening for the mixture comprising the sample and the competitor, said outlet opening being connected to the inlet opening of the metering chamber;
• that the mixing device is configured so that the competitor is present in the mixture in a predetermined concentration;
• that the second sensor is configured to capture a second metering signal relative to the concentration of the competitor bound to the second receptor and is connected to a computer, which computer is configured to determine the concentration of the second ligand in the sample from the second metering signal and from the concentration of the competitor in the mixture.