Abstract: An assay device comprises a sample-collecting wick made from non-woven fabric material laminated to plastics sheet. Preferably, the fabric is a 30:70 blend of viscose and polyester, and has a fibrous structure in which more than two thirds of the fibers run substantially parallel to the intended direction of liquid flow in the wick.

Abstract: An assay result reader, for use in conjunction with an assay device comprising a porous liquid-permeable carrier in the form of a strip or sheet through the thickness of which electromagnetic radiation is transmissible, the carrier including a detection zone in which an assay result is revealed by specific binding of a detectable material directly or indirectly to a binding agent immobilized in the detection zone, detection of the detectable material being effected by determining the extent to which electromagnetic radiation transmitted through the thickness of said carrier is attenuated by the presence of the detectable material bound in the detection zone.

Abstract: Storage stability of an assay device, comprising an assay strip and sensitive reagents such as antibodies within a plastics casing, is maintained by moulding some or all of the casing from dessicant-containing plastics material, especially a blend of about 60-65% polystyrene and about 30% silica dust. Ideally the desiccant-containing plastics material is used in the moulding of a removable cap for the device. The cap can be made by sandwich injection moulding, using the dessicant-containing polystyrene as a core, surrounded by conventional polystyrene.

Abstract: Enhanced extraction and assay of solubilized lipopolysaccharide antigens from bacteria such as Chlamydia by the use of a buffer containing an anionic polysaccharide, especially heparin, and surface active agent, especially CHAPS or CHAPSO.

Abstract: An antibody specific for a target analyte is purified by affinity chromatography on a substrate bearing a low-affinity analogue of the target analyte. The antibody is displaced from the substrate by contact with a second analogue of intermediate affinity, which remains complexed with the antibody. This complex can be used in a conventional assay for the target analyte, which displaces the intermediate-affinity analogue. The complexed antibody is rendered more storage-stable because the second analogue protects the antibody binding reagion.

Abstract: A magnetic stirrer wherein a relatively weakly magnetised disposable stirrer bar inside a closed container, for example a stirrer bar moulded wholly of non-isotropic ferrite, is moved with a stirring action from outside the container by a relatively powerful magnetic driver, preferably consisting of a pair of permanent magnets of neodymium boron driven in rotation as an assembly.

Abstract: An analytical device for determining the presence and/or concentration of an analyte in a sample liquid comprises a hollow casing; an assay strip within said casing for selectively capturing an analyte in sample liquid applied to the device; a bibulous sample liquid receiving member at or adjacent to a first extremity of said casing which collects sample liquid and transports it into the casing; a window in the casing at a location remote from the first extremity of the casing; and a single cap which can be applied in turn over the window during sample collection, and then over the sample receiving member.