Abstract: Disclosed is a primary chromatographic support containing an immobilized flocculating agent for use as a separation media for a secondary support consisting of microparticles used in affinity separation and heterogeneous immunoassays. In a specific embodiment, a flocculating agent such as polyethyleneimine is immobilized on a chromatographic resin packed in a column. The column so formed is then used to trap microparticles having an affinity ligand or binder for the ligand affixed thereon. Such microparticles are used as a solid support for the affinity reaction involved in a variety of immunoassay formats.

Abstract: Antivenoms to snake, spider, scorpion and jelly fish venoms are produced for the treatment of humans and animals, and for analytical use. The antivenom is purified with an antigen matrix containing a single whole venom or a plurality of whole venoms covalently attached to an insoluble support such as aldehyde-activated agarose. Preferably, the whole venoms forming the plurality of whole venoms are selected from the four whole venoms from C. atrox, B. atrox, C. adamanteus and C. durissus terrificus. A combination of immobilized C. atrox and C. durissus terrificus whole venoms can substantially purify antivenom reactive with all four venoms. The antivenom can be horse or avian such as chicken antivenom.

Abstract: A chelating agent is covalently bonded to a biologically active molecule such as an enzyme or antibody, the biologically active molecule is contacted with a support containing a bound transition metal ion whereby the metal ion is chelated by the chelating agent and the oxidation state of the metal ion is changed by treatment with an oxidizing or a reducing agent to provide a kinetically inert: oxidation state to immobilize the biologically active molecule on the support. The transition metal ion is preferably Co(II), Cr(II) or Ru(III) and the oxidation state of the metal ion is changed to Co(III), Cr(III) or Ru(II), respectively. The chelating agent can be iminodiacetic acid, nitrilotriacetic acid, terpyridine, bipyridine, triethylenetetraamine, biethylenetriamine, 1,4,7-triazacyclonane or a chelating peptide. Certain chelating agents can immobilize more than one biologically active molecule at a metal ion site on the support.

Abstract: A method for carrying out a binding assay is described wherein a member of a specific binding pair (sbp) and a sample are combined with a matrix of non-porous beads in a liquid medium under conditions such that the beads bind to the sbp member. The liquid medium is removed from the beads by aspiration using an aspiration tube having one or more orifices each of a diameter smaller than the minimum diameter of the smallest bead thereby allowing removal of the liquid medium while prohibiting aspiration of the beads.

Abstract: A biological fluid collection container comprising a cup member, a lid assembly removably mounted to the cup member having a housing with a downwardly extending cylindrical skirt, a luer lock with a throughgoing bore extending from one side of the lid housing. A hollow tube extends from the other side of the lid housing adjacent the luer lock and is axially aligned with the throughgoing bore of the luer lock. The hollow tube is provided with a plurality of throughgoing holes leading into its lumen along its surface to provide for a sampling along various liquid level layers of the biological fluid specimen collected in the cup member so that when the biological fluid specimen is removed from the cup member a representative sampling is obtained.

Abstract: On a slab-like board formed of a transparent material is closely attached a wedge-shaped transparent cover member provided with a recess in a central inner portion, thereby to form a clearance. The height of the clearance between the recess and the board is configured to decrease continuously or in steps. When an immunological active substance such as a monoclonal antibody is caused to sensitize carrier particles F, and a reagent having the carrier particles F dispersed into a liquid medium mainly composed of the water is mixed with a specimen, the reaction will occur in which the flocculate is formed from plural carrier particles. When this reaction liquid is poured into the clearance through the opening, the reaction liquid penetrates in the direction having a narrower vertical spacing due to surface tension. A single carrier particle unflocculated can move deep within the recess because it is small in diameter, but the flocculate G is trapped on its way and can not move because of its size.

Abstract: Disclosed is a primary chromatographic support containing an immobilized flocculating agent for use as a separation media for a secondary support consisting of microparticles used in affinity separation and heterogeneous immunoassays. In a specific embodiment, a flocculating agent such as polyethyleneimine is immobilized on a chromatographic resin packed in a column. The column so formed is then used to trap microparticles having an affinity ligand or binder for the ligand affixed thereon. Such microparticles are used as a solid support for the affinity reaction involved in a variety of immunoassay formats.

Abstract: Methods and devices are provided for carrying out assays with minimal technical training where quantitative visual determinations may be made. The devices provide for a flow-path where a sample receiving element is moved from a sample receiving position to a position where it serves to bridge a transport element and a measurement element, so that the sample may be transported from the sample element to the measurement region. Labelled conjugates are provided which migrate a distance into the measurement region related to the amount of analyte in the sample.

Abstract: A method is provided, in one embodiment, for the determination of an analyte in a biological fluid sample in the presence of a substance interfering with an assay for the analyte. This embodiment is implemented by using antibodies to cause the selective immunoreaction of at least one of the analyte or the interfering substance and then conducting an assay for the analyte in at least one of the immunoreactants or the non-reactants. Another embodiment provides a disposable reaction device to implement the method. The invention is applicable to the detection of a wide variety of analytes, including cholesterol in a targeted lipoprotein class in the presence of cholesterol in another class; to targeted isozymes of enzymes such as creatine kinase, lactate dehydrogenase, amylase, and alkaline or acid phosphatases in the presence of other isozymes; as well as to targeted immunoglobulins in the presence of non-targeted immunoglobulins.

Abstract: A biologic sample such as feces, sputum, cervical tissue, pleural fluids, exudates, cytologic specimens, or the like, is tested for the presence or absence of: ova; parasites; microorganisms; inflammatory, neoplastic tissue cells; or other target materials which are indicative of infestation, disease or infection. The sample is mixed with a buffer fluid and placed in a transparent tube which contains a volume-constricting cylindrical insert for gravimetric separation of components of the sample. The mixture is centrifuged, and the annular space between the insert and tube bore is examined under magnification for the presence of the target materials.

Abstract: A method is provided for removing a second ligand from a particle surface without substantially affecting the particle surface, comprising the step of exposing the particle to a first ligand immobilized onto a support, wherein the particle is exposed under conditions and for a residence time sufficient to allow the second ligand to desorb from the particle surface, and wherein the first ligand has an affinity for the second ligand that is at least two orders of magnitude greater than the affinity of the second ligand for the particle surface, such that the second ligand is removed from the particle surface without substantially affecting the particle surface.

Abstract: There is disclosed a process and a device for detecting and measuring (1) the amount of enzyme present as a detecting system following a nucleic acid hybridization reaction or immunoreaction; (2) the level and activity of free enzyme in a biological sample; (3) the level of enzyme from contaminating microorganisms present in a sample; and (4) enzymes from pure culture isolates for microbial identification and antimicrobial susceptibility testing.

Abstract: A patient's health is diagnosed by centrifuging blood samples in a transparent tube, which tube contains one or more groups of particles such as lyposomes or plastic beads of different densities for each group. Each group of density-defined particles carries antigens or antibodies which are specific to a complement antigen or antibody which may be in the blood sample being tested, and which are indicative of the patient's health. A label-tagged antibody which is specific to all bound antibody/antigen couples is added to the blood sample so as to form labeled antibody+antigen-antibody complexes (AAAC) in the blood sample. Upon centrifugation, the complexed particles will settle out in different areas in the tube according to the respective density of the particles, and the degree of label emission of the particle layers can enable qualitative or quantitative analyses of the blood sample to be made.

Abstract: A method of detecting target antibodies or antigens by reaction with specific binding partners thereto is disclosed. One of the target or the binding partner is bound to a carrier, and the other is unbound. The complex between the target and the binding partner, with one being carrier-bound, forms an optically detectable binding complex. A microreaction vessel having an upper portion, a transition portion and a lower portion is utilized, wherein the upper portion has a greater diameter or width than the lower portion, and the transition portion is situated between the upper portion and the lower portion, and is funnel shaped. The microreaction vessel contains a slurry or suspension of inert particles, and unbound target or binding partner thereto. A solution of the carrier bound target or binding partner thereto is added to the vessel, which is then centrifuged to produce an optical determination of the target.

Abstract: The present invention relates to a process for determining or detecting by immuno adherence a biological substance present in a sample, which consists in introducing the sample into a receptacle on whose walls there is a component which has a specific immunological affinity for the substance to be tested for, in adding magnetic particles on which there is a substance which has a specific immunological affinity for the substance to be tested for, in subjecting them to several successive magnetic actions in order to accelerate the deposition of the said particles onto the walls and to displace those which have not formed specific bonds with the substance to be tested for which adheres to the walls via the component with affinity which is fixed thereto, and in observing the particles deposited.

Abstract: A porous shaped substrate such as a porous bead is formed from polyacrylonitrile or a copolymer thereof containing nitrile groups. The substrate has a hydrophilic surface containing amide groups constituting about 1.8 mole percent to less than about 15 mole percent of the total nitrile groups, and containing no amide or carboxyl groups. The substrate is substantially non-swellable in water and is able to resist pressures in a columnar bed of up to about 3000 psi without collapsing. In forming the amide groups, polyacrylonitrile or copolymer thereof containing nitrile groups, an alkaline catalyst such as sodium hydroxide and a nonsolvent for the substrate such as methanol are combined to form a suspension. A peroxide is added to the suspension and the suspension is heated to hydrolyze nitrile groups to amide groups. Succinylated aminoethyl groups or activated carboxyl groups can be formed on the substrate and a bioactive ligand such as p-aminobenzamidine covalently bonded to the substrate.

Abstract: Disclosed is a primary chromatographic support containing an immobilized flocculating agent for use as a separation media for a secondary support consisting of microparticles used in affinity separation and heterogeneous immunoassays. In a specific embodiment, a flocculating agent such as polyethyleneimine is immobilized on a chromatographic resin packed in a column. The column so formed is then used to trap microparticles having an affinity ligand or binder for the ligand affixed thereon. Such microparticles are used as a solid support for the affinity reaction involved in a variety of immunoassay formats.

Abstract: A method and assay for determination of functionality of steroid receptors present in breast or other tumors. The method is useful for determination of cancer responsiveness to hormonal therapy by establishing a correlation between functioning estrogen receptors and those which are dysfunctional or nonfunctional. The assay is useful for determination whether the cancer, particularly the breast cancer, will respond to anti-estrogen hormonal therapy.

Abstract: A microorganism detection system provides initial warning, confirmation of dentity, and recognition of pathogenic factors in microorganisms from environmental samples. The method and apparatus of the invention uses different sized antibody coated microspheres which react with unknown antigens, are sized by electronic volume sizing, and are sorted by size. The sized particles are quantitated in addition to being sized. The microsphere sizes indicate the presence of specific microorganism groups.The samples can be further analyzed using fluorescent microspheres which agglutinate with the sized microspheres. The presence of specific microorganisms is indicated by a change in the fluorescence of the sample.

Abstract: A cell surface antigen determination method for determining an immunocyte having an immune antigen-antibody complex composed of an antigen and an antibody combined therewith in a liquid which contains immunocytes having various antigens and also containing many kinds of antibodies, and an apparatus used in this method. In accordance with the inventive method and apparatus, non-specific reactions are restrained so as to reduce the background without using a complement.

Abstract: The present invention provides a process for the specific determination of pancreatic .alpha.-amylase in the presence of salivary .alpha.-amylase in body fluids by reaction with a system for the detection of .alpha.-amylase with the use of an inhibitor for salivary .alpha.-amylase, wherein, as substrate, there is used a compound of the general formula: ##STR1## in which R.sub.1 is a straight-chained or branched alkyl or alkoyl radical containing up to 6 carbon atoms, a cycloalkyl or cycloalkoxyl radical containing 3 to 6 carbon atoms or a benzoyl, benzyl or phenyl radical which is optionally hydrophilically substituted, R.sub.2 is a hydrogen atom or in which R.sub.1 and R.sub.2 together form a methylene bridge, the hydrogen atoms of which, independently of one another, can each be substituted by an alkyl radical containing up to 5 carbon atoms or a phenyl radical, Gluc is a glucose molecule, n is 1, 2 or 3 and X is an optically determinable residue.

Abstract: Specific binding methods are used for diagnostic assays and purification separations whereby the specific binding capture reagent is prepared from copolymers having highly reactive carboxy groups. These groups are extended from the polymer surface with a linking group having from 8 to 50 atoms in the chain and two or more alkylene, arylene, alkylenearylene or arylenealkylene groups. To these reactive groups is attached a biologically active substance such as a protein or oligonucleotide which then participates in the diagnostic assays or purification separation methods.

Abstract: An adsorbent for an autoantibody or immune complex produced by combining an autoantibody with its homologous antigen, which comprises a water-insoluble porous material and a compound having an anionic functional group immobilized onto said material, an apparatus for removing an autoantibody or immune complex thereof using the above-mentioned adsorbent and a method for removing an autoantibody or immune complex thereof from body fluid by passing body fluid through the above-mentioned removing apparatus. According to the present invention, the autoantibody or immune complex thereof can be selectively removed from body fluid without removing useful components in body fluid.

Abstract: Use of a lithium salt, particularly lithium thiocyanate, as an agent for lysing red blood cells and denaturing hemoglobin in the performance of an immunoassay to detect the relative amount of a hemoglobin derivative in a blood sample. The method is particularly useful in the determination of hemoglobin Alc. The method provides a rapid means for releasing hemoglobin from red blood cells by lysis and for exposing the epitope that is characteristic of the Alc form. Low concentrations of the lithium salt provide rapid release and denaturation of hemoglobin without the need for dilution prior to the performance of the immunoassay.

Abstract: Physiological samples are typed for HLA-B27 by contacting the sample with an antibody which binds to HLA-B7 and is not cross-reactive between HLA-B7 and B27, separating the sample from any complexes which are formed, and then testing the sample for the presence of HLA-B27 with an antibody which is cross-reactive for HLA-B7 and B27 in a STAT test. Particularly, an enzyme conjugate is used which binds to a membrane allowing for the detection of any HLA-B27 bound to the membrane.

Abstract: A biologic sample such as feces, sputum, cervical tissue, pleural fluids, exudates, cytologic specimens, or the like, is tested for the presence or absence of: ova; parasites; microorganisms; inflammatory, neoplastic tissue cells; or other target materials which are indicative of infestation, disease or infection. The sample is mixed with a buffer fluid and placed in a transparent tube which contains a volume-constricting cylindrical insert for gravimetric separation of components of the sample. The mixture is centrifuged, and the annular space between the insert and tube bore is examined under magnification for the presence of the target materials.

Abstract: A method of assessing glycosylated haemoglobin in a sample, wherein the method comprises the steps of (a) contacting the sample with signal-forming molecules comprising a conjugate of one or more dihydroxyboryl residues or salts thereof, linked to a signal-forming label; (b) separating by selective precipitation from a homogenous solution, glycosylated and non-glycosylated haemoglobin and any molecules bound thereto, from the reaction mixture of step (a) above; and (c) assessing signal-forming molecules selected from the group consisting of signal-forming molecules which have bound to the separated haemoglobin, and non-haemoglobin bound signal-forming molecules. Steps (a) and (b) may be performed simultaneously or sequentially. The sample may optionally be haemolyzed to liberate any cell bound haemoglobin. The invention also comprises an analytical test kit for use in accordance with the method of the invention.

Abstract: A method for performing a diagnostic immunoassay by a solid phase separation. To a reaction mixture of a test sample and labeled antibody, which forms a complex of any analyte present in the test sample, is added a solid phase material having a compound capable of binding any excess labeled antibody. The solid phase material is chosen to rapidly settle whereby a solid and liquid phase is formed. The liquid phase can then be extracted to measure the amount of analyte-labeled antibody present therein.

Abstract: The invention is directed to a method of purifying sequentially synthesized peptides and oligonucleotides by affinity techniques. Selected products are capped with and N-terminus capping agent for peptides or a 5'-terminus capping agents for oligonucleotides, and then bound with affinity agents that are selective for the corresponding capping agents.

Abstract: Processes using affinity cell separation are used to increase the yield and purities of target cells by increasing the cell:affinity surface contact rate, limiting the shear force on the attaching cells and/or using an appropriate affinity surface area.

Abstract: There is disclosed a process and a device for detecting and measuring (1) the amount of enzyme present as a detecting system following a nucleic acid hybridization reaction or immunoreaction; (2) the level and activity of free enzyme in a biological sample; (3) the level of enzyme from contaminating microorganisms present in a sample; and (4) enzymes from pure culture isolates for microbial identification and antimicrobial susceptibility testing.

Abstract: The invention relates to a method of binding biologically active organic ligands to hydroxyl groups of polymeric carriers. The method involves bringing 4-fluorobenzenesulfonyl Chloride into reactive contact with the hydroxyl groups of polymeric carriers in such a manner to form sulfonate groups in place of the hydroxyl groups. The ligand is then brought into reactive contact with the hydroxyl groups of polymeric carriers to replace the sulfonate groups reacted with the organic ligand. The polymeric carrier containing the bound ligand can be used to isolate a biologically active material from a heterogeneous solution.

Abstract: An immunoassay procedure for detection of analytes in urine wherein an immunological reaction is conducted in an aqueous phase containing the urine and a filterable immunocomposite containing an inherently colored gold sol particle is formed if the assay is positive. The colored, gold sol particle containing immunocomposite is collected for direct visual observation on a filter element.

Abstract: A method of purifying LFA-3 using affinity chromatography. Purified LFA-3 is useful for quantitating or separating out CD-2-containing cells.

Abstract: A monoclonal antibody reactive with a C-terminal half of human lymphotoxin, and fragments thereof; a hybridoma cell line producing a monoclonal antibody reactive with a C-terminal half of human lymphotoxin; a process for the production of a monoclonal antibody reactive with a C-terminal half of human lymphotoxin, comprising the steps of culturing the above-mentioned hybridoma in a medium to secrete the antibody, and recovering the antibody from the culture supernatant; a process for the production of a monoclonal antibody reactive with a C-terminal half of human lymphotoxin, comprising the steps of inoculating a hybridoma to a mammal, obtaining ascites from the mammal, and recovering the monoclonal antibody from the ascites; a process for the production of a hybridoma cell line producing a monoclonal antibody reactive with a C-terminal half of human lymphotoxin, comprising the step of immunizing a mammal with a conjugate of zinc and a purified recombinant human lymphotoxin, obtaining spleen cells from the imm

Abstract: A method of immunologically determining free human protein S in an assay sample, which comprises contacting a primary antibody fixed to an insoluble solid carrier and a labelled secondary antibody with the assay sample, the primary and secondary antibodies having the property of binding to different epitopes of free human protein S, and one of the primary and secondary antibodies being a monoclonal antibody having the property of not binding to a complex of the human protein S and human complement cofactor C4b-binding protein (C4bp) but specifically binding to the free human protein S.

Abstract: Disclosed are methods that permit the determination of both lipid moiety (LM) and apolipoprotein expressed epitope immunoreactivity (EEI) of intact isolated lipoprotein species. One format of the method isolates a lipoprotein species by means of a ligand binding to a solid phase, and quantitates thereafter the LM and/or the EEI. A complementary variant format provides for nonquantitative study of a constant number of lipoprotein particles exploring the sizes of the particles (LM) and scanning the apolipoprotein epitopes (EEI). Disclosed also is a method using lipid moiety dynamics (LMD) and expressed epitopes immunoreactivity dynamics (EEID) to explore the lipid loading and unloading of the lipoprotein species during a fast-feeding cycle. Both the LMD and EEID of lipoprotein particles may be performed as a panel, individual or in any combination. This can be used to detect abnormalities in lipid metabolism that precede the hyperlipidemias associated with cardiovascular disease.

Abstract: A device for immunological techniques is prepared containing a macroporous hydrophobic synthetic polymer cloth having antibodies or antigens directly adsorbed therein and directly absorbed and immobilized thereon. The cloth has a thickness of more than about 200 .mu.m and has spaces between fibres exceeding about 20 .mu.m in diameter, and preferably has a Frazier Air permeability, in CFM/ft.sup.2 at 0.5" H.sub.2 O of from about 215 to about 750 for thickness of from about 11 to about 40 mils such that it can accommodate a large volume of liquid per surface area, that it has a large surface area, and that it has minimum flow resistance. In immunoassays antibodies may be directly adsorbed therein and directly absorbed and immobilized thereon, and specific antigens from a selected test sample, may then be captured by the antibodies, to be detected conventionally.

Abstract: A method for the preparation of a labelled target-specific virus where the binding sites on the virus are not inactivated by the label material. And a three-step process for detection of a targeted microorganism, the first step comprising contacting of labelled target-specific virus with a sample suspected of containing a target microorganism, the second step comprising the capture of the labelled virus/microorganism complexes onto a solid matrix, and the third step comprising the detection of said complexes on the solid matrix. The process is highly sensitive and can be used for rapid detection of target microorganisms in clinical, food, pharmaceutical, cosmetic and environmental samples. The invention further concerns a device and a kit based on the inventive process.

Abstract: The present invention provides a method for selectively recovering fetal cells from a maternal blood sample. The method comprises the following steps. Cells of the sample are combined with a first and a second antibody labeled with different fluorochromes for a period of time sufficient for antibody binding to produce labeled cells. The antibodies are specific for two different antigens expressed by two material HLA alleles. In a preferred embodiment, the alleles are of an HLA locus for which the woman is heterozygous. Cells having two different fluorescent labels are separated from cells having either a single fluorescent label or unlabeled cells using fluorescence-activated cell sorting. The separated single-labeled and unlabeled cells are recovered. The separated fetal cells can be used in a variety of procedures including DNA amplification methods and karyotyping.

Abstract: The invention relates to an assay for one or more analytes which comprises contacting a sample suspected of containing one or more analytes with a solid phase containing one or more different antigen specific antibodies separately immobilized to defined areas on the solid phase, followed by indirectly detecting the presence of bound antigen by titrating the unbound immobilized antibodies with a titrating antibody which is specific for the first antibody. This assay allows the simultaneous detection of a multiplicity of antigens in a single assay.

Abstract: A method for evaluating the potential immunogenicity of a protein derived from recombinant DNA technology. The method involves injecting an animal with the recombinant protein and then isolating antiserum from the animal. The antiserum is depleted of antibodies to a reference protein, i.e., a plasma derived protein, by adsorbing the antiserum against the reference protein. The adsorbed antiserum is then blotted against the recombinant protein, to see if any antibodies were produced which recognize the recombinant protein, but did not recognize the plasma-derived protein during adsorption.

Abstract: Means for the detection of free ligand analogue conjugate in fluids from competitive ligand-receptor assay processes. Ligand analogue antibodies that bind the ligand analogue conjugate with substantially greater affinity than their affinity for target ligand are selected and used in competitive ligand-receptor assay processes to bind the free fraction of the ligand analogue conjugate. This means permits the detection of the free fraction of ligand analogue conjugate even in the presence of substantially higher concentrations of free target ligand. For the purposes of the present invention, ligand analogue antibodies are antibodies that exhibit at least 100.times.greater affinity for the ligand analogue conjugate compared to their affinity for the target ligand.

Abstract: The present invention provides cleavable conjugates whose linkers contain a labile bond that is cleavable under a variety of mild conditions, including weakly acidic. Since the agent may be bonded directly to the linker, cleavage can result in release of native agent. The invention also provides methods for producing cleavable conjugates. Preferred agents include drugs, toxins, biological response modifiers, radiodiagnostic compounds, radiotherapeutic compounds, and derivatives thereof. The targeting molecule employed in the invention may be an intact molecule, a fragment thereof, or a functional equivalent thereof. In a particularly preferred embodiment, the targeting molecule is a monoclonal antibody directed towards a tumor-associated antigen in man. The invention further provides methods for delivering to the cytoplasm of a target cell an agent free of its targeting molecule carrier.

Abstract: A method for separating plasma from red blood cells and a device utilizing the method in which a low-pressure filter is interposed in a pathway between an inlet port and a reaction area. The sole driving force for the movement of plasma from the filter to the reaction area is capillary force provided by a tubular capillary. The filter is selected from glass microfiber filters of specified characteristics, which can operate in the absence of agglutinins, and filters capable of separating agglutinated red cells from plasma, which require the use of an agglutinin.

Abstract: A method for evaluating the potential immunogenicity of a protein derived from recombinant DNA technology. The method involves injecting an animal with the recombinant protein and then isolating antiserum from the animal. The antiserum is depleted of antibodies to a reference protein, i.e., a plasma derived protein, by adsorbing the antiserum against the reference protein. The adsorbed antiserum is then blotted against the recombinant protein, to see if any antibodies were produced which recognize the recombinant protein, but did not recognize the plasma-derived protein during adsorption.

Abstract: A method of quantitatively analyzing an analyte contained in a whole blood sample, wherein a dry multi-layered analysis element is used. The method provides particular merits when the used multi-layered analysis element has no light-shielding layer which is interposed, in the conventional analysis element, between a coloring reagent layer and a blood cell separating layer, so that red coloring matters of blood cells are detected from the support side during the step of measuring the optical density of the reflected light.

Abstract: A quantitative immunoassay for a beta-lactam antibiotic in a sample, which may contain open and closed ring forms of the antibiotic, is disclosed. Closed-ring forms of the antibiotic in the sample are converted to open-ring protein conjugates and detected through immunospecific reaction with antibodies raised against the open-ring protein conjugate form of the beta-lactam antibiotic.

Abstract: The performance of double receptor, specific binding assays is improved by use of a receptor complex having the structureA.sub.BL (BL).sub.n A.sub.1wherein BL is a binding ligand, A.sub.BL is a receptor specific for binding ligand, A.sub.1 is a receptor, BL is covalently bonded to A.sub.1 and A.sub.BL is reversibly bonded to BL. Generally A.sub.BL is absorbed onto an insoluble surface and A.sub.1 is an antibody to the substance being assayed. The complex has particular utility in coated tube and rechargeable radioimmunoassay systems.

Abstract: Methods and compositions are provided for concentrating particles in a minute area on a solid surface. The method permits the detection of small amounts of analytes by providing for an observable signal in relation to the concentration of particles in the area.