Abstract: A test card incorporates a colorimetric indicator test to determine the presence of a minute amount of a specific substance in a liquid medium. The test card includes top and bottom sheets adhesively secured to an intermediate frame member which, together with the top and bottom sheets, defines a filter chamber having a flat filter therein which incorporates a test portion. The test portion of the filter has a binding substrate to which antibodies of the specific substance have been bound. This binding substrate is in communication with a test port. In the method of the invention a substance to be tested is administered through the test port and contains an unknown amount of antigen. After the sample is administered an aqueous solution of enzyme labelled antigen is administered and, subsequently, a liquid substrate is added to cause a color change in the filter below the test port inversely proportional to the amount of antigen contained in the sample administered at the test port.

Abstract: An analytical device for fluid samples includes a fluid sample well means connected to a sample initiation area in such a fashion that the assay will not commence unless sufficient sample is introduced into the sample well means to conduct the assay. Once sufficient sample has been deposited into the sample well means, the sample flows into an initiation area and the assay commences.

Abstract: An analyzer system for automatic column chromatography includes chromatographic columns which are mounted in a rack. A drop removal mechanism system shakes the rack to transfer the last drop of eluate from the tip of a chromatographic column to a receptacle below the tip before the column is repositioned over another receptacle and another fluid or operation is introduced into the column. This prevents one eluate from contaminating another. The chromatographic column may have an upper end which is sealed by a foil member. During use, the foil member is ruptured by lowering a pressure cylinder with a seal-punching head against it. The pressure cylinder, which is part of the pressure tip unit, is then withdrawn so that fluid can be introduced into the column via the ruptured foil member. The pressure tip unit is then lowered into sealing engagement with the column so that pressure can be applied via a bore in the pressure cylinder.

Abstract: An apparatus for filtering multiple biological samples using a filter membrane is disclosed. The apparatus comprises a base plate, a well plate, a gasket, and a first vacuum member for vacuum-clamping the base plate, well plate, gasket and filter membrane together. The apparatus may further comprise a second vacuum member for drawing the biological samples from the well plate into contact with the filter membrane.

Abstract: An apparatus for use in a ligand-receptor assay procedure for the quantitative determination of the concentration of a target ligand in a liquid sample. The apparatus contains top and middle plates having holes therethrough. The holes in the two plates are in axial alignment and the holes in the middle plate have sidewalls that extend below the bottom surface of the middle plate. The apparatus contains a bottom chamber having an opening on the upper side thereof facing the bottom surface of said middle plate. The chamber contains at least one port extending through a surface thereof to permit a vacuum to be created within said chamber and means for accepting a microtiter plate containing a plurality of wells. When the microtiter plate is positioned within the chamber, the ends of the holes extending beneath the bottom surface of the middle plate are located within the wells.

Abstract: Screening methods to obtain suitable antibodies for use in immunoassays for analytes not ordinarily susceptible to detection by this means involves in vitro screening of panels of cells secreting a representative selection of antibodies. An application of this method also permits the preparation of specific mimotopes which mimic the immunological activity of the desired analyte, which mimotopes can then be used as competitors in the immunoassay or can be used to immunize subject mammals in order to improve the specificity and affinity of the antibodies. Methods to identify a particular analyte by its pattern of binding strength to a panel of related antibodies and to match an arbitrary analyte with an immunoreactive member of a panel of candidate antibodies are also disclosed.

Abstract: For collecting a batch of liquid samples, such as in the laboratory testing of body fluids, there is provided a collecting sheet having an array of resiliently deflectable fingers formed in the sheet. The fingers can be deflected out of the plane of the sheet to dip into respective liquid containers such as wells in a microtiter plate so as to absorb liquid samples therefrom. When released, the fingers snap back into the plane of the sheet retaining the liquid samples therein.

Abstract: A reagent coating material has been developed to modify the surface of articles used in assay procedures. Polymers of chitosan solubilized with an organic acid form into thin films when contacted to glass, plastic, metal or cellulose articles. The coated article may be used directly for immobilizing agents for assay, or may be further modified to increase the range of usefulness. The reagent coating solution itself may also be reacted to produce an activated reagent with surface coating properties. The invention embodies a kit of use in immunoassay procedures.

Abstract: An analyzer system for automatic column chromatography, and method for its use, includes an array of chromatograph columns and multi-cell cuvettes associated with each column. Chromatographic separation takes place under a constant, low fluid pressure. A pressure system distributes air to each column during chromatographic separation but prevents leakage of air if the column array is partially empty. The multi-cell cuvette collects and separates the eluates associated with a single column. The system provides for automatic removal of caps from the bottoms of the chromatograph columns and provides for automatic optical density reading.

Abstract: A miniature chamber assembly that provides a miniature capillary environment in which a liquid medium containing microscopic-size particulate material can be placed for study under a microscope. The assembly includes components which do not wet relative to the liquid medium. The assembly provides a miniaturized capillary environment that can contain the liquid medium for a period of time sufficient to enable observation while preventing deterioration of the medium.

Abstract: A method for performing a microparticle diagnostic assay in a device having a shallow sample well for receiving a sample and reagents for forming a reaction mixture, a read well positioned adjacent to said sample well and separated from said sample well by a wall which is constructed and arranged such that when wash fluid is injected into said sample well, sample and reaction mixtures are washed from said shallow sample well, over the wall and into said read well. The steps of the method comprise forming microparticle analyte complexes in said shallow sample well; washing said microparticle analyte complexes from said shallow sample well over the wall and into said read well where a fibrous matrix retains and immobilizes said microparticle analyte complexes; adding to said read well an indicator substance capable of forming an assay signal when said microparticle analyte complexes are present; and detecting said assay signal produced by said indicator substance.

Abstract: Methods for identifying individuals at increased risk of diabetes are disclosed. The methods disclosed utilize the discovery of the DQw3.2 variant, which identifies a specific allelic polymorphism at a sinle gene locus. One preferred method utilizes a labeled probe to detect the DQw3.2 allele. This method involves estimating the size of the hybridizable DNA fragment generated by a specific restriction endonuclease and therefrom determining the presence of the allele. A second preferred method involves the serologic detection of the DQw3.2 allele. Within this method, immunocomplexes formed between two different MAb's and separate portions of a cell collection are detected and the presence or absence of the allele determined.

Abstract: A method for drying mammalian cells, such as erythrocytes, lymphocytes, leukocytes and platelets onto a solid-phase support for use in solid-phase immunoassays through use of a drying solution and an article for use in immunoassays prepared by such method. The method comprises immobilizing a monolayer of cells onto the solid-phase support by non-covalent binding. This is accomplished by staining the solid-phase support with an organic dye having a net positive charge which permits non-covalent binding of the cells which carry a net negative charge to the solid-phase support. These cells are dried or fixed to the solid-phase support by addition of a drying solution which comprises an aqueous solution of a monosaccharide, disaccharide, trisaccharide or cyclitol and a salt. The preferred monosaccharide is D-(-)glucose and the preferred salt is sodium chloride. The preferred drying solution comprises a 1.0 M solution of dextrose and a 154 mM solution of sodium chloride.

Abstract: Single base pair differences between otherwise identical DNA fragments can result in an altering of the melting behavior which can be detected by denaturing gradient gelelectrophoresis (DGGE). A method has been developed for efficient transfer of genomic DNA fragments from the gel following DGGE. The DGGE is run in a polyacrylamide gel (PAG) containing 2% low gelling temperature agarose (LGT). The PAG is crosslinked with a reversible crosslinker, and after electrophoresis the crosslinks are cleaved and 80-100% of the DNA fragments are transferred to nylon membranes by alkaline transfer. Hybridization with gene specific probes is then performed. The technique has been used to identify an RFLP in the COLIA2 gene.

Abstract: A filter apparatus for filtering a plurality of liquid or gas fluid samples containing particles to be filtered, such as bacteria or cells. The apparatus includes a filter; a device for simultaneously and independently filtering fluid samples on the filter; and apparatus for force filtering the samples. The device for simultaneously and independently filtering fluid samples includes at least one gasket including a plurality of through perforations held clamped in a sealed manner against one face of the filter by appropriate clamps. The clamps have perforations located for being brought into alignment with the perforations through the gasket and for cooperating therewith to put an upstream face of the gasket into communication, via the filter, with a plurality of independent inlets for samples of fluid to be filtered, and to put a downstream face of the gasket into communication with a plurality of likewise independent outlets for the fluid samples.

Abstract: The vehicle comprises a sample receiving reservoir (15), a plurality of test stations each comprising an FCFD or other capillary fill sensor cell (3), and passage (22) for providing fluid communication between the reservoir and a conduit with which end portions of said cells communicated such that in use sample from the reservoir may be fed to the plurality of cells substantially simultaneously. The vehicle makes it easier to know time zero for each assay. Passage (22) providing fluid connection may comprise at least one pore in a wall of the reservoir, the or each pore being of a size such that surface tension of the liquid normally prevents escape of ligand. Rotation of the vehicle breaks surface tension and liquid is released into the conduit.

Abstract: A microbiological analysis cup having a flat bottom, a wall with a circular section connected to this flat bottom and an open end. Moving from the flat bottom wall of the cup, there are at least three superposed tapered zones whose respective base diameters increase from the flat bottom to the open end.The cup makes it possible to work with very small volumes of bacterial suspension for short incubation periods, which makes it very economical to use.

Abstract: A method and kit for typing platelets in whole blood for human leucocyte antigens (HLA). A panel of HLA antigens is made on a microtiter plate. Each well is contacted with serum to be typed and the amount of reaction is followed with anti-human (Fab '2) alkaline phosphatase and disodium p-phenylphosphate.

Abstract: A dipping element for immunoassay or quantitative analysis of an immunoreactive analyte is disclosed having a first matrix having a carrier therein containing an immobilized antibody capable of an immunochemical reaction with a sample antigen. The immobilized antibody is not released into the aqueous liquid sample upon contact. The element further comprises a second matrix which contains labelled antigen which does dissolve in the aqueous liquid sample upon contact. On dipping, the marker-labelled antigen reacts with the immobilized antibody in competition with the antigen-antibody reaction between the analyte antigen and the immobilized antibody. if the analyte is an antibody, then the second matrix contains a marker labelled antibody and the first matrix contains an immobilized antigen. Methods for the quantitative analysis of an analyte antigen or antibody are also disclosed.

Abstract: A method of determining levels of extrinsic and intrinsic clotting factors and protein C based upon the reaction rate of the observed clot formation and the first derivative of the reaction rate of observed clot formation is provided. In accordance with the teachings of the invention, the reaction rate of the observed clot formation in a prothrombin time test or an activated partial thromboplastin time assay is determined for both test and normal plasma samples and the reaction rates compared. In another embodiment, the first derivative of the reaction rate of the observed clot formation is determined and the results compared.

Abstract: An improved simplified enzyme-linked immunosorbent assay (ELISA) for the diagnosis of viral, fungal, bacterial and parasitic diseases. The diagnostic test is designed for use in non-laboratory settings where the usual equipment and supplies, including running water, may not be available. Collected blood samples are applied to a previously prepared test plate having an antigen coating covered by a layer of agar. After incubation to cause antibodies from the samples to bind to the antigen coating, the agar layer is stripped off and a conjugate is applied in the form of a species specific enzyme-linked anti-immunoglobulin. After incubation to cause this conjugate to bind to the antibody-antigen coating, a previously prepared chromogen agar paper (CAP) impregnated with an enzyme substrate and acceptor, if needed, in agar is applied over the conjugate. After incubation to cause a color reaction, the results are read and interpreted in comparison with known standards.

Abstract: An instrument (50) automatically determines the concentrations of HDL cholesterol, LDL cholesterol, total cholesterol and triglycerides for a sample (80) of whole, anticoagulated blood placed in a doughnut shaped container (10). The sample (80) is first separated into its blood cell and plasma (84) constituents using high speed centrifugation (54) and a thixotropic gel (82). Part of the plasma (84) is then deposited in an HDL separation chamber (14) where LDL cholesterol and VLDL cholesterol are precipitated by a reagent and the precipitant is sedimented by high speed centrifugation (54) against V-shaped grooves (40) in the outermost wall (38) of the HDL separation chamber (14). Part of the plasma (84) is diluted ten-fold. The supernatant in the HDL separation chamber is then placed in a cuvette reaction chamber (b 18) where it reacts with a cholesterol reagent. The diluted plasma is placed in two other cuvette reaction chambers (18) where it reacts with chloesterol and triglycerides reagents, respectively.

Abstract: Separation of anionic oligosaccharides on a preparative scale with high resolution can be achieved by anionic exchange chromatography using PEI-derivatized supports.

Abstract: A sample of a body fluid, such as blood, is collected in a cartridge having a sample chamber for storing the sample and one or more calibration chambers, each for storing a respective calibration fluid. The fluid sample is drawn ino the sample chamber by placing the sample chamber in fluid communication with a needle inserted into the fluid sample and applying a vacuum to the chamber using either a syringe or internal vacuum. A body fluid sample may also be drawn into the sample chamber from a syringe or capillary tube containing the fluid sample. The cartridge may be either planar or cylindrical. The chambers of a cylindrical cartridge may be either elongated voids symmetrically positioned about the longitudinal axis of the cartridge or axially spaced annular voids.

Abstract: A rotary fluid manipulator utilizable as a diagnostic device includes a porous body having fluid passages defined therein by fluid blocking means in the porosities of the body such as openings or slots in the body or compaction of areas of the porous body to define fluid passages therebetween. Various substances or binding partners such as receptors, immunoassay or other assay test materials and test specimens can be deposited on the porous body to permit various types of tests to be made by rotation of the manipulator to cause conjunctive centrifugal and wicking induced flow of fluids deposited thereupon.

Abstract: There are described assay devices having a control surface on which controls are deposited to produce a representational symbol that preferably indicates a satisfactory test procedure, or a failure in the test procedure. In one aspect of the invention, the symbol comprises exclusively the positive control areas and the negative control area, so that the negative control area will convert the "satisfactory" symbolism into "unsatisfactory" symbolism. In another aspect, the symbols that are formed are "OK" and "OK", respectively.

Abstract: A solid phase immuno-assay system for assaying at least one analyte, in the form of a solid support having a plurality of receptors bound thereto. At least two of the receptors conjugate with the same analyte.A reaction container comprising a plurality of longitudinally arranged individual compartments, and a longitudinally extending single compartment.A card for assaying a plurality of samples for the same analyte, having a plurality of receptors for the analyte at different locations on the card.A method of performing an assay for the same analyte in more than one sample, by providing a receptor for the analyte at more than a single location on a solid substrate; exposing each of the receptors to different samples; and developing each of the receptor locations to indicate the presence of the analyte in each of the samples.

Abstract: A biochemical reagent comprises an oligosaccharide, preferably one which has been liberated from an immunogenic glycoprotein or proteoglycan, which is immobilized on a carrier via an intermediate spacer molecule such as a lipid. The lipid molecule should preferably have at least two long lipid tails so that the oligosaccharide is held in spaced relationship to the carrier where is exhibits antibody-binding ability which is almost indistinguishable from that of the original glycoprotein or proteoglycan. The reagent has its application in biochemical testing of oligosaccharides and systems which bind to them.

Abstract: An immunoassay which is capable of simultaneously detecting any desired number of antigens of one infectious agent, or combinations of antigens of several infectious agents, or any desired number of immunoglobulins of one infectious agent, or combinations of immunoglobulins of several infectious agents on a single solid support. A test sample is contacted with a solid support on which one or more antigens are immobilized as discrete test sites. Antigen-antibody complexes are formed and detected on the solid support.

Abstract: The present invention provides a one-step process for the detection of the presence of an allergy and for the specific detection of the allergen responsible for the allergy, in which the leukocytes of a sample to be investigated are incubated with an allergen or with another stimulation factor in an aqueous medium together with a chromogenic protease substrate and calcium ions, the liberated protease is reacted with the chromogen and the resulting chromophor is determined. The protease activity is measured kinetically after an incubation period by the increase of the chromophor concentration. The present invention also provides a reagent and a device for carrying out this process, as well as a process for the determination of antiallergic and anti-inflammatory substances. The device consists of a microtiter plate with a plurality of different reagents arranged in rows.

Abstract: A multi-well test plate which includes a base and a plurality of well strips. The well strips are removable from the base and the individual wells of each strip are separable. The wells in each strip are joined by T-shaped connecting members which hold the wells in a flat linear array when the well strips are either held in or removed from the base and the T-shaped members are readily severable to permit easy separation of individual wells. The bottom wall of each well is a microporous membrane.

Abstract: A method and apparatus for the measurement of clot formation times, clot dissolution times, or clotting parameters is disclosed. This method performs these measurements by monitoring movement of magnetic particles incorporated in the sample being assayed, where the movement is induced by a magnetic field.

Abstract: An inoculation device preferably for use in the testing of a fluid sample such as urine. The device includes a capillary flow system which allows for immediate and contemporaneous inoculation of a plurality of reagent pads forming part of a test substrate. The flow system includes a plurality of nozzles and a support structure which directs flow into the individual reagent pads while avoiding cross-contamination.

Abstract: An antibody matrix immunoassay device for determination of number and proportion of subpopulations of leukocytes is described. The device can be used to evaluate and monitor the immune status of an individual and to diagnose and monitor the progression of AIDS.

Abstract: An apparatus and method for in vitro bleeding time determination. Blood is placed in a tube having a window covered with a clot promoting material having a slit. The time required before blood stops flowing through the slit is recorded, and is the bleeding time. It is preferred that the clot-promoting material be nylon fabric impregnated with collagen and blood clot promoting proteins.

Abstract: A multi-well test plate which includes a base and a plurality of well strips. The well strips are removable from the base and the individual wells of each strip are separable. The wells in each strip are joined by T-shaped connecting members which hold the wells in a flat linear array when the well strips are either held in or removed from the base and the T-shaped members are readily severable to permit easy separation of individual wells.

Abstract: The invention comprises a prefilled and presealed apparatus for carrying out chemical, particularly immunochemical, analyses in non-laboratory environments. The apparatus comprises a test base containing therein wells, into which are introduced all the reagents necessary for performing the assay reaction in question. The apparatus further comprises a reagent stick having at one end a sharp reactive point onto which a sample to be assayed can be adsorbed. The base and wells are covered with an impervious foil layer which can easily be pierced with the sharp reactive end of the testing stick included in the apparatus, thereby allowing the adsorbed sample to contact the reagents used in carrying out the assay.

Abstract: Cells which produce antibodies which bind carbohydrate epitopes of glycoproteins are identified by screening with mucinous body fluids in raw, or preferably partially purified, form. Fine differences in antibody specificity may be detected by further screening with mucinous body fluids treated to alter the carbohydrate epitope interest, e.g., removal of sialic acid from a sialosyl Lewis-a epitope. The selected antibodies may be used in immunopurification, immunodiagnosis and immunotherapy.By this method, antibodies have been found whose binding to carbohydrate epitopes such as sialosyl Lewis-a is relatively insensitive to pH. Such antibodies are of particular value in immunological methods where pH is a consideration.

Abstract: Methods and devices for separating bound label from unbound label within an assay mixture and for predispensing assay reactants in self-contained assay vessels, as well as a method for detecting the presence and/or amount of an analyte within a fluid sample, and a reusable detection vessel for use therein and with specific binding assays in general are disclosed. Significant to the separation of bound label from unbound label is the use of a cushion comprising generally one primary layer and in some cases one or more secondary layers.

Abstract: The invention concerns an immunological assay system, wherein the inner face of the cuvettes is used as the solid phase. The equipment includes a displaceable carriage (8) for the cuvette set as well as, above the carriage, a dosage head (9), to which the liquid dosimeter (11) and the measurement device (19) are attached. All the operations take place automatically.

Abstract: A method for performing an assay to differentiate between related taxa of micoorganisms, comprising the steps of providing a support having a plurality of zones, each zone comprising immobilized antibody to an enzyme found in a particular microorganism, wherein the antibody in the zone is specific to the enzyme, but not to corresponding enzyme of other taxa to be determined in the assay; contacting the zones with a sample suspected of containing one of the particular microorganisms; permitting enzyme in the sample to become bound by antibody in one or more of the zones; and determining which of the taxa were present in the sample by determining to which of the zones the enzyme has become bound. The determining step may comprise adding a substrate for the enzyme to the support after the enzyme has become bound thereto, wherein the substrate, after being acted on by the enzyme, creates a detectable signal.

Abstract: Determination of a plurality of species of antibodies or antigens is attained by a method which comprises forming a plurality of different kinds of reaction membranes each having a different species of antibody or antigen on an electrophoretic carrier, superposing these reaction membranes, optionally superposing a filter on the laminate of reaction membranes, inserting the laminate in an electrolyte, adding a plurality of different species of antigens or antibodies corresponding to the plurality of species of antibodies or antigens supported in the aforementioned reaction membranes, electrophoretically moving the added antigens or antibodies through the electrolyte and enabling them to react with the antibodies or antigens supported on the reaction membranes, and measuring the concentrations of either the antigens or antibodies resulting from the reaction or the antibodies or antigens supported in an unreacted form on the reaction membranes.

Abstract: An automated immunoassay analyzser comprising a transfer route on which test plates each having a plurality of chambers for immunological reaction opened upwards are transferred continually with a constant interval of time, and devices of at least A, B, C and D described below which are arranged on the transfer route from upstream to downstream in the order referred to in which the device A is for injecting the sample comprising a vertically and horizonally driven support, a pipet fixed to the support, and a nozzle tip usable for a single sample and removably attached to the lower end of the pipet, the device B is for B/F separation and the device C is for injecting the substrate solution and both devices are integratedly combined and comprise a vertically and horizontally driven support, a washing tube supported by the support, a temperature controllable solution reservoir block fixed to the support, a substrate injection tube provided to the lower side of the reservoir block, the washing tube and the substr

Abstract: An automated pipetting system for performing programmed pipetting procedures on an array of fluid containing test tubes, vials or wells. The system includes a frame which is placed above a horizontal table which holds the array. The frame is equipped with a pair of X-axis guide shafts and a pair of X-axis helical screw shafts. A subframe which is mounted on the X-axis guide shafts is equipped with a pair of Y-axis guide shafts and a Y-axis helical screw shaft. A carriage is mounted on the Y-axis guide shafts and at least one row of probes is mounted on the carriage. A Z-axis drive independently drives the probes in a Z-axis direction relative to the array.

Abstract: An analyzer system for automatic column chromatography, and method for its use, includes an array of chromatograph columns and multi-cell cuvettes associated with each column. Chromatographic separation takes place under a constant, low fluid pressure. A pressure system distributes air to each column during chromatographic separation but prevents leakage of air if the column array is partially empty. The multi-cell cuvette collects and separates the eluates associated with a single column. The system provides for automatic removal of caps from the bottoms of the chromatograph columns and provides for automatic optical density reading.

Abstract: A kit and method have been developed which can be used to simultaneously detect antibodies to two HTLV or HIV antigens. The kit includes a solid carrier material, such as a microtest plate, having immobilized thereon a mixture of first and second viral antigens. The antigens are from any of HTLV-I, HTLV-II, HIV-I and HIV-II provided, however, that HTLV-II antigen is mixed only with HTLV-I antigen. The kit also comprises labeled-antibodies which are reactive with both the first and second antibodies in a test sample. A biological sample, such as a blood sample, is assayed by contacting it with the immobilized antigens to form reaction products between the immobilized antigens and the antibodies in the sample, followed by contact with the labeled antibodies to form labeled reaction products which can be detected in a suitable manner. The kit and method are useful for rapid screening of biological fluids.

Abstract: Apparatus for performing and measuring chemical reactions includes a reaction test apparatus having reaction wells wherein reactants are controllably mixed, and exposure apparatus which receives and positions the reaction test apparatus adjacent a photographic film. Each of the reaction wells includes at least two reaction cups, arranged one above the other. The uppermost reaction cups have orifices in the bottoms, so that liquid can be mixed and reacted in the uppermost cup, and then controllably transferred to the lower cup to be mixed with additional reactants. In a preferred embodiment, the reaction cups are supported in plates that are structurally integral with the cups, and are superimposed to make a test block. The test block is retained in the exposure apparatus, and liquid is forced from the upper cup to the lower cup by application of pressure to the top of the upper cup.

Abstract: An agglutination analyzing vessel for use in an immunological agglutination reaction in which there is provided a liquid-absorbable member made of porous material in at least a portion of an inclined bottom surface of a well provided in the analyzing vessel. A solution for a test liquid is absorbed into the liquid-absorbable member to cause a liquid flow directed downwardly in the test liquid. This downward liquid flow promotes the sedimentation of particles. Thus, both agglutination and non-agglutination particle patterns can be formed on the bottom surface of the vessel within a short time period.

Abstract: An assay device is provided which includes a support, generally planar and elongated in shape, upon which a biological binding reaction may take place. This assay support includes in its broadest aspect, three sections, a sample receiving well section at one end and a gripping section at the opposite end, with a connecting section therebetween. The sample receiving well section includes at least two spaced-apart receiving wells, generally at the end of the assay support, for the addition of binding reactants. Each of the wells has an open end on a first face of the support, a concave inner surface extending concavely into the support, and a convex outer surface which projects convexly from an opposed face of the support. These wells may serve as a depository to contain aliquots of binding reagents, as well as a sample under analysis, the sample under analysis possibly containing a substance that will bind to the binding reagents.

Abstract: An aqueous wash solution is buffered to a pH of from about 5 to about 9 and contains at least about 0.01 weight percent of a compound comprising a dodecyl sulfate anion and an alkali metal or ammonium cation, such as sodium dodecyl sulfate. This wash solution is particularly useful in a method for the determination of an immunological ligand. Particularly, it is useful for washing the immunological complex formed between the ligand and a receptor molecule therefor. Unreacted materials can be readily separated from the complex by the washing, particularly if the separation is carried out using a filtration membrane in a test device. a test kit for ligand determination comprises the wash solution as well as one or more receptors for the ligand, at least one of which is labeled for detection. This kit is particularly useful for measuring human chorionic gonadotropin (hCG) as an early indicator of pregnancy.