Capillary immunoassay and device therefor comprising mobilizable particulate labelled reagents

An analytical test device for detecting an analyte suspected of being present in a liquid biological sample and requiring solely the application thereto of said liquid biological sample to enable a test to be performed and a test result to be provided, said device comprising:

• a hollow casing constructed of moisture impervious solid material;
• a test strip, comprising a dry porous carrier disposed in said casing, said dry porous carrier comprising a test result zone and a control zone;
• and
• a labeled reagent capable of specifically binding with said analyte to form a first complex of said labeled reagent and said analyte, said labeled reagent being positioned within said casing as part of said dry porous carrier prior to use, said labeled reagent being a particulate direct label,
• said casing comprising a sample application aperture through which liquid biological sample can be applied directly or indirectly to said carrier, said labeled reagent being located upstream from said test result zone prior to use and released into mobile form by application of said liquid biological sample,
• wherein said carrier comprises, immobilized in said test result zone, means for binding said first complex, and wherein migration of said applied liquid biological sample through said dry porous carrier conveys by capillarity said first complex to said test result zone of said dry porous carrier, whereat said binding means binds said first complex thereby to form a second complex and to thereby indicate the presence of said analyte in said liquid biological sample,
• said casing further comprising a test result observation aperture remote from said sample application aperture, said test result zone at least being visible through said test result observation aperture, said sample application aperture and said test result observation aperture being spaced apart and disposed so that sample liquid can be applied to said sample application aperture to initiate said test but said test strip is substantially shielded from accidental initial application of sample liquid directly to a portion of said test strip downstream from said location of said labeled reagent in the dry state,
• wherein said control zone comprises a material for indicating that said liquid biological sample has been conveyed thereto by capillarity along said carrier irrespective of a presence or absence of said analyte in said liquid biological sample.