An apparatus for use in an immunoassay process for the detection of a target antigen in a a fluid sample which includes a ''dip-stick'' type device (12) having affixed to a portion of the surface thereof a solid polymeric carrier member (14) with a capture reagent (20) against the target antigen strongly bound to a portion of its surface and at least one container in which a target antigen containing sample and a labelled capture reagent against the target antigen may be admixed and the dip-stick device (12) may be inserted to contact the admixture of the target antigen containing sample and the labelled capture reagent to the target antigen. The presence of labelled capture reagent on the ''dip-stick'' device is indicative of the presence of the antigen in the sample.
