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 immobilised 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 reaction 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.