Analyte assaying by means of immunochromatography with lateral migration

A device for determining an analyte in a liquid sample, comprising:

• a capillary action support, defining a reference capillary direction and comprising:
• a liquid sample deposit area;
• and
• an analyte-detection area disposed downstream of said deposit area, the analyte-detection area comprising a first detection area, and a second detection area disposed downstream of the first detection area;
• an area comprising a first analyte-specific binding reagent that is merged with the liquid sample deposit area, the first analyte-specific binding reagent being conjugated to a visible and/or measurable marker and being free to migrate when wet by means of capillary action in the capillary action support along the reference direction, and
• a second analyte-specific binding reagent immobilized in the first detection area,
• wherein:
• the analyte, or an analogue of the analyte, is directly fixed the capillary action support within the second detection area and disposed at a distance from the second specific binding reagent;
• the first detection area is configured to determine the analyte in the liquid sample by a sandwich assay;
• the second detection area is configured to determine the analyte in the liquid sample by a competition assay;
• and
• the device is configured to detect:
• a weak analyte concentration by the absence of a first signal in the first detection area and the presence of a second signal in the second detection area;
• a strong analyte concentration by the absence of the first and second signals in the first and second detection areas, respectively;
• and
• a normal analyte concentration by the presence of the first and second signals in the first and second detection areas, respectively.