An analytical test device incorporating a dry porous carrier to which a liquid sample, eg. urine, suspected of containing an analyte such as HCG or LH can be applied indirectly, the device also incorporating a labelled specific binding reagent which is freely mobile in the porous carrier when in the moist state, and an unlabelled specific binding reagent which is permanently immobilized in a detection zone on the carrier material, the labelled and unlabelled specific binding reagents being capable of participating in either a sandwich reaction or a competition reacts on in the presence of the analyte, in which prior to the application to the device of a liquid sample suspected of containing the analyte, the labelled specific binding reagent is retained in the dry state in a macroporous body, eg. of plastics material having a pore size of 10 microns or greater, through which the applied liquid sample must pass en route to the porous carrier material, the labelled specific binding reagent being freely soluble or dispersible in any liquid sample which enters the macroporous body.
1. An immunoassay test device, comprising: a test strip comprising: a porous sample receiving member configured to receive a liquid sample, a macroporous body, a porous nitrocellulose strip comprising a detection zone, an analyte or an analogue thereof immobilized in the detection zone, and a labeled reagent comprising a particulate label portion and a first binding reagent capable of binding the analyte or the analogue thereof, the particulate label comprising a colored particle, the labeled reagent is disposed in the macroporous body in a dry state and is mobilizable by the liquid sample that passes along a flow path, and the labeled binding reagent is configured to competitively form a complex with analyte present in the liquid sample or with the analyte or the analogue thereof immobilized in the detection zone, wherein, the test strip defines the flow path along which the liquid sample received by the sample receiving member can pass to the macroporous body and thereafter to the porous strip and formation of an immobilized complex in the detection zone is indicative of the absence of the analyte in the liquid sample.
2. The immunoassay test device of claim 1 , wherein the macroporous body and the porous carrier are made of different materials.