Abstract: A method of monitoring the aggregation of cells in, for example, an immuno-agglutination assay, comprises promoting agglutination sonically in a capillary and inverting the capillary to cause agglutinated particles to settle at a meniscus. The granular appearance of agglutinated cells can be distinguished visually from the smooth distribution of non-aggregated cells.

Abstract: The present invention provides reagents for a detectable label for use in specific binding assays. Specifically, modified .beta.-galactosidase enzyme donors (ED) and acceptors (EA) are utilized. Both ED and EA are modified to form separate ED and EA complexes by coupling each with a linking element and a binding moiety which is specific to a binding site in the analyte. The ED and EA complexes are incapable of forming active enzyme in the absence of the analyte. However, when analyte is present, ED and EA complexes which bind to a common analyte in a sample, active .beta.-galactosidase is formed.

Abstract: A novel bidentate conjugate has two different chemical moieties, or bidentate members, attached through an adequate spacer moiety. Each bidentate member acts as a small molecule ligand and is capable of specifically binding to a different macromolecular substance. The bidentate members are relatively small molecules, usually less than about 7,000 Daltons in size. The spacer moiety is selected so that both bidentate members can simultaneously bind to their respective specific binding partners. Where the specific binding partners are multivalent, large complexes can be formed. The formation of these complexes can be inhibited by the presence of an unconjugated monovalent bidentate member, such as free analyte from a test sample. The bidentate is of particular use in turbidimetric or nephelometric inhibition immunoassay procedures.

Abstract: A rapid, competitive enzyme linked immunosorbent assay (cELISA) for the determination of Bluetongue virus antibodies in serum is described. This method utilizes either a biotinylated monoclonal antibody to Bluetongue virus and streptavadin-enzyme in conjunction with synthetic substrate, or an enzyme-conjugated monoclonal to detect antibodies specific for Bluetongue virus.

Abstract: A sandwich method, in which heparin coupled to a carrier, a sample and an antibody labeled with a labeling agent, brings about a high sensitivity for detecting and/or measuring FGF.

Abstract: An agent for the determination of apolipoprotein B in blood, plasma or serum by an agglutination method, containing a dispersion of particles to which antibodies against Apo B are bound, as well as an agglutination method, are described.

Abstract: In order to measure the concentration of an analyte in a liquid sample the sample is contacted with a receptor molecule having binding sites for the analyte and labelled with a first marker, whereby a fraction of the binding sites on the receptor molecule become occupied by the analyte, the sample being contacted with such a small amount of the receptor, having regard to its affinity constant with the analyte, that only an insignificant fraction of the analyte becomes bound to the receptor. The receptor having fractionally occupied binding sites is then back-titrated by means of a back-titration technique involving a system including a second marker different from the first, and the relative strengths of the two signals produced by the two markers are measured to provide a value representative of the fractional occupancy of the binding sites on the receptor molecule by the analyte.

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: A method for determining the amount of an analyte in a sample fluid utilizes a multilayer assay element which comprises at least one reagent layer and a light-blocking layer. The assay method includes the steps of optically reading a signal producing species, e.g. a fluorescent label, a first time before the sample fluid is applied to the assay element and a second time, at the same wavelength and in the same location within the assay element, after the sample fluid has been applied to the assay element and the sample analyte has interacted with the reagent(s) present in the assay element. The ratio of the two signals is taken and compared with that for known amounts of the analyte to determine the amount of analyte in the sample fluid.

Abstract: A new ligand binding assay is based upon measurements of relaxation rates of the solvent, which are obtained with a magnetic resonance (MR) spectrometer. It is termed a solvent mediated relaxation assay system (SMRAS). SMRAS is based on the observation that the enhancement of proton relaxation rates produced by a magnetic material can be modulated by the binding of various analytes to a magnetic material. Hence the relaxation rate of the solvent can be interpreted to give information on the concentration of an analyte.

Abstract: A system for analyzing a chemical reaction provides control of the temperature and volume of the reagents to improve the accuracy and precision in quantitative measurements of specific proteins and other immunochemistries in body fluids. The reaction occurs in a cuvette within a nephelometric optics module. A sensor senses the temperatures of reaction buffer liquids as they flow into the cuvette, and a heat exchanging device increases or decreases the temperatures of the buffer liquids. A control circuit responsive to the temperature sensor controls the heat exchanging device to maintain the temperature of the buffer liquids and the cuvette within a selected temperature range. The system may also include a sample pickup station, a sample probe for withdrawing a selected sample from the sample pickup station, a sample preparation station, and a sample transport for carrying said sample from the sample preparation station to the reaction cuvette.

Abstract: To determine the biological activity of protein S in a sample of human plasma, the suitably diluted sample is added to a substrate formed from plasma deficient in protein S, in which protein C is activated. The functionality of protein is evaluated by a coagulometric test using bovine thromboplastin with added calcium as the phospholipid source. Also disclosed is a kit for determining the activity of Protein S in a human plasma sample. The kit includes a first reagent which is human plasma deficient in protein S, a second reagent which contains an activator for protein C, and a third reagent which contains bovine thromboplastin.

Abstract: An improved, copolymer-based immunoassay system, method, and apparatus is highly sensitive and effective in accurately measuring extremely low concentrations, such as 10.sup.-6 to 10.sup.-12 grams per milliliter, of biologically active substances, such as monoclonal or polyclonal antibodies and antigens, cancer markers, proteins, bacteria, viruses, therapeutic drugs, drugs of abuse, and food and water contaminants in fluid samples. The system requires no sample preparation, and is reliable, easy to use, sufficiently low in cost to be readily usable in doctors' offices, small labs, and other low-volume facilities, but is also readily adaptable to hospital and high-volume use. The new system, method, and apparatus for agglutination immunoassay systems includes novel and coordinated carrier particle technology, light application and measurement and chemistry, coacting to provide the multiple advantages of simplicity and accuracy in use, and extreme sensitivity in application, in quantifying immunoassays.

Abstract: Conjugates of salicylic acid and certain poly(amino acids), which are either antigenic or enzymes, are provided. Antibodies raised against the antigenic poly(amino acids) and the enzyme conjugates are used as reagents in immunoassays.

Abstract: A time-resolved fluorometer, having a light tight enclosure, for detecting the presence of an analyte in a sample. Within the light tight enclosure are a pulsed dye laser that produces a pulsed light beam for sample excitation, a light tight sample excitation station through which samples, treated with a reagent composition, are passed into the path of the pulsed light excitation beam to produce a delayed fluorescence emission, a fused silica lens system through which the delayed fluorescence emission passes and an assembly which selectively amplifies, counts and characterizes the resulting emissions. The operation and coordination of the time resolved fluorometer are under computerized control as are the readings reported. Significant improvements relate to the fused silica lens systems and interference filters, cooling of the emission measurement apparatus and particularly the improved performance resulting from the combination of these aspects.

Abstract: The present invention provides a process for the determination of a bindable analyte according to the principle of heterogeneous immunoassay by incubation of a sample solution which contains the analyte with a labelled first receptor specifically bindable with the analyte and present in dissolved phase and a second receptor present in a solid phase which does not cross-react with the first receptor and can fix a complex which contains the analyte and first receptor, separation of the phases after incubation and quantitative measurement of the labelling bound to the solid phase, wherein there is determined the back dissociation velocity of the labelling bound to the solid phase into the dissolved phase and the quotients of the back dissociation velocity and measurement value are used as a measure for the correctness of the test result of the first measurement.

Abstract: Chemiluminescent 1,2-dioxetane compounds are disclosed in which the molecule is stabilized at the 3-position on the dioxetane ring against decomposition prior to the molecule's coming in contact with a labile group-removing substance (e.g., an enzyme that will cleave the labile group to cause the molecule to decompose to form at least one light-emitting fluorophore) and substituted at the 4-position on the dioxetane ring with a fused polycyclic ring-containing fluorophore moiety bearing a labile ring substituent whose point of attachment to the fused polycyclic ring, in relation to this ring's point(s) of attachment to the dioxetane ring, is such that the total number of ring atoms separating these points of attachment, including the ring atoms at the points of attachment, is an odd whole number. These odd pattern substituted compounds decompose to emit light of greater intensity and of a different wavelength than that emitted by the corresponding even pattern substituted isomers.

Abstract: A new reporter mechanism for biospecific reactions is disclosed. This mechanism involves interligand metal ion transfer in which a metal ion is directly transferred from one chelate complex to another following the occurance of the biospecific reaction. The second chelate complex is separate from and detectably different than the first chelate complex. This invention can take the form of methods of chemical analysis and kits for conducting such methods. In preferred embodiments of this invention the detectable difference is a difference in fluorescence, such as an increase or decrease which occurs as a result of the formation of the second chelate. In further preferred embodiments the difference in fluorescence is detected using fluorescent background rejection methods.

Abstract: A method and apparatus for use in quantifying, in a whole blood sample in which the red cells are lysed, a component which will react with a reagent to form an antigen-antibody complex, the method comprising mixing the sample with the reagent to obtain the complex, exposing the sample to a source of radiation and measuring the intensity of radiation scattered through a given angle by the complex, and the apparatus including a container for receiving the sample which has been treated with the reagent to the component, the container being transparent to radiation having a wavelength falling within a given band width, typically 460-530 nm. A source of radiation within this band width is provided together with a device for detecting the intensity of radiation scattered through a given angle by the sample.

Abstract: A method is described for kinetic measurement of enzyme activity bound to a solid matrix which improves both the sensitivity and speed of one immunoassay method. The immunoassay typically consists of reaction of the analyte with two specific antibodies, one fixed to the surface of a polymeric bead or wall of a test tube, the other added in solution and labeled by covalent coupling to an enzyme. By reaction between analyte and both antibodies, the enzyme-labeled antibody becomes fixed to the surface in a quantity proportional to the quantity of the analyte. After washing sufficiently to remove unreacted enzyme-labeled antibody, fixed enzyme activity is measured by incubation with a substrate and measurement of the rate of the reaction catalyzed. Fixation of the enzyme causes the reaction products to be localized near the surface. To measure the concentration of reactant or product repeatedly during the reaction, the solution must be mixed before each measurement, which can interfere with the measurement.

Abstract: This invention provides a means for determining the concentration of any of a wide range of antibody or antigen molecules with a high degree of specificity, accuracy and sensitivity. Antigen or antibody concentration is determined by effecting an agglutination reaction in a liquid medium and determining the cluster size distribution of agglutinated particles by optical pulse particle size analysis. The measured cluster size distribution then is compared with a standard quantitative relationship between the cluster size distribution and concentration of the antigen or antibody being tested. By this means one may specifically ascertain the absolute concentration of the antigen or antibody in question in the sample being analyzed. In addition to detecting antigen or antibody molecules, the process of this invention can be used to determine the concentration of any substance capable of specifically promoting or inhibiting an agglutination reaction such as viruses, white blood cells or the like.

Abstract: An element and method for easily performing liquid assays are disclosed. The element uses capillary action to draw a predetermined volume of a liquid sample into a reaction chamber charged with reagent, where reaction between the liquid sample and the reagent is monitored.

Abstract: An immunological assay method, wherein the concentration of a substance to be assayed is calculated from a calibration curve, which is formed in the preparation of a reagent or in the assay of a sample based on parameter(s) determined in the preparation of the reagent, without the need of forming any additional calibration curve each time, is disclosed. By the immunological assay method of the present invention, the concentration of the substance to be assayed can be efficiently and discontinuously determined, when compared with conventional ones. The method of the present invention is particularly suitable for quantitatively determining an antigen or an antibody.

Abstract: The peak verify time for kinetic nephelometric measurements of reactions between antigens and antibodies is adjusted as a function of the magnitude of the peak rate order to reduce the time required for peak verification. The scatter signal is zeroed following the end of the peak verification period and the reaction is tested for antigen excess. Reactions during the antigen excess check having rates that exceed a threshold value are accepted as being valid, and no additional measurements are made for such samples. Reactions during the antigen excess check having rates that are less than the threshold value are rejected as being in antigen excess. Samples found to be in antigen excess are diluted and then reanalyzed.

Abstract: A method for immunological assay of IgM antibodies against at least one said antigen in a liquid sample containing at least IgM and IgG antibodies, such as a biological fluid, comprising reaction of said liquid sample and of antibodies against IgG, and addition to the so obtained reaction product of the said antigen bound to finely divided particles and of a free said antigen, the amount of IgM being inversely proportional to the amount of unagglutinated finely divided particles.

Abstract: A method is provided for simultaneously measuring total cellular DNA and incorporated nucleoside analog. The method entails altering the cellular DNA of cells grown in the presence of a nucleoside analog so that single stranded and double stranded portions are present. Separate stains are used against the two portions. An immunochemical stain is used against the single stranded portion to provide a measure of incorporated nucleoside analog, and a double strand DNA-specific stain is used against the double stranded portion to simultaneously provide a measure of total cellular DNA.The method permits rapid flow cytometric analysis of cell populations, rapid identification of cycling and noncycling subpopulations, and determination of the efficacy of S phase cytotoxic anticancer agents.

Abstract: A method is described for the in vitro determination of hypersensitivity to an allergen. The method consists of adding the allergen to a sample containing basophilic leucocytes from the blood of a patient, and then measuring the amount of degranulation of the leucocytes. The allergen is added slowly and continuously, such that the threshold concentration needed to cause degranulation of sensitized leucocytes is reached sometime during the addition step and is present for a long enough period of time to allow degranulation to occur.

Abstract: The present invention discloses a method and a kit for monitoring human exposure to genotoxic agents. The method comprises an immunoassay for detecting in human serum specific antibodies against DNA adducted to an agent suspected of being genotoxic. A kit comprising various components for performing the assay is also disclosed.

Abstract: In its broadest aspect, the present invention provides a method of assaying a ligand in a sample which comprises contacting the sample with a predetermined quantity of a specific binding partner to the ligand, said specific binding partner being immobilized on the effective gate electrode of a field effect transistor, and determining whether (and, if desired, the extent to which) an appropriate transistor characteristic is changed as a result of complex formation between the ligand and the specific binding partner.

Abstract: A photometric method and apparatus for measuring agglutination in a biological agglutination reaction system test sample using a laser beam source and at least one photodetector for detecting light scattered by the test sample. The method includes the following steps: (1) arranging the at least one photodetector so as to be capable of detecting scattered light from the test sample at a scatter angle of 30 to 60 with respect to a laser beam directed at the test sample from the laser beam source; (2) irradiating the test sample with the laser beam from the laser beam source; (3) selectively detecting the intensity of scattered light from the test sample at the scatter angle of 30 to 60 using the at least one photodetector which provides an output indicative thereof; and (4) determining the first derivative of the output of the at least one photodetector with respect to time and obtaining the maximum value thereof.

Abstract: Endotoxin contents in samples can be determined qualitatively, or quantitatively, singly or in parallel, with high precision in a short time by a process comprising applying a light to each sample solution, measuring an initial transmitted light amount I.sub.0 and a transmitted light amount at a time t, I(t), to give a ratio R(t)=I(t)/I.sub.0, and judging a gelation point by a threshold value of R(t), or further obtaining a gelation time from the gelation point. An apparatus used therefor is also disclosed.

Abstract: Competitive or inhibition assays are disclosed in which sample (e.g., containing target antigen), a reagent containing first particles (e.g., antibody-coated light particles) and a reagent containing second particles (e.g., antigen coated heavy particles) are reacted in a centrifugal field. Differential migration of first particles, of second particles and of first particles linked to second particles leaves a concentration of particles at a locus in solution after a time, which concentration is a function of the analyte concentration in the sample.

Abstract: A sample is mixed with a reagent containing stably suspended particles coated with a binding pair member complementary to or competitive with the target binding pair member. A centrifugal force applied during reaction is sufficient to change the concentration of particles at a locus relative to overall particle concentration. Light transmission or scattering is measured kinetically at the locus, especially in a microcentrifugal analyzer.

Abstract: An immunoassay of the type which utilizes the hemolysis of microcapsules such as red blood cells. Microcapsules which can be lysed by complement activity, which contain an optically determinable substance, on whose surfaces an antibody to be quantified is bound are prepared. The microcapsules, a test sample containing the antigen or the antibody to be quantified, and complement are mixed to react each other. Thereafter, an optical measurement is conducted at different wavelengths for the reaction mixture which is still suspending the intact microcapsules.

Abstract: The present invention relates to polyfunctional hydrophilic spherical microparticles of uniform size which contain from 5 to 95% of units originating from the copolymerization of an aldehyde of the formula ##STR1## R.sub.1 being an alkyl radical, from 5 to 90% of units originating from the copolymerization of an acrylic acid ester of the formula ##STR2## in which R.sub.2 is H or alkyl and R.sub.3 is a hydroxyalkyl group, less than 15% of units originating from an acrylic acid derivative chosen from amongst ##STR3## R.sub.4, R.sub.5 and R.sub.6 being alkyl radicals, and from 0.1 to 10% of units originating from a crosslinking product.The invention also relates to a process for the preparation of the said microparticles and to the use of these microparticles for the nephelometric determination of HB.sub.s antigen.

Abstract: The method for determining endotoxin concentrations in samples and, if present, interfering factors by adding defined amounts of endotoxin to the sample and computational evaluation of the reaction kinetics can be improved by adding, to at least two identical preparations of a sample, different amounts of endotoxin. These endotoxin amounts, however, are at least ten times the amount of the endotoxin to be determined in the sample. By determining a regression line as the reference curve from the measured values, the endotoxin amount of a preparation of the sample to which no endotoxin has been added is determined. The effect caused by interfering factors and the endotoxin neutralization capacity can be determined from the slope and position of the regression line. The absorbance in a turbidimetric measurement may be enhanced by using a small amount of a chromogenic substrate whereby a reduction in the amount of the sample preparation to be assayed will be possible.

Abstract: A method for determining allergenic sensitivity of a mammal is disclosed. The method involves measuring the time required for hemostasis of a blood sample with an allergen in the presence of a blood clotting inhibitor and comparing the time required for hemostasis in the presence of a blood clotting inhibitor and the absence of the allergen. The sensitivity to the allergen is determined by determining the difference in time required for hemostasis.

Abstract: Serological investigations according to the principle of the Complement Fixation Test (CFT) can be evaluated by means of a kinetic method by using an excess of complement. Preferably the amount of the complement in the reagents and the control samples are balanced against one another.

Abstract: An improved radioimmunoassay test method and device based upon competitive binding test methods wherein immunoreactions are halted at a time when the rate of change of the quantity of bound radiolabeled analyte of interest is inversely proportional to the concentration of analyte of interest in an unknown sera. Based thereon, a test device is created having a single calibration curve 36 which is accurate throughout the shelf life of the device.

Abstract: There is disclosed a method for immunoassay and/or competitive binding assay, wherein an excess amount of unlabeled antigen is added after the start of the reaction between the labeled ligand, the unlabeled ligand, and the binding agent or antibody, to saturate or flood the antibody binding sites. This provides increased sensitivity allowing for more reliable and precise measurements of ligands including antigens than heretofore. The present method extends the scope of applicability of competitive binding technique for assay of hormones, drugs and other compounds.

Abstract: Methods and compositions are provided for performing an assay on whole blood samples. The method is for a determination of an analyte which is a member of a specific binding pair (sbp) consisting of ligand and homologous receptor. The method involves a binding agent for the red blood cells in such sample, a solid bibulous element to which is bound at least one sbp member, and a signal-producing system. The method comprises combining the whole blood sample, the binding agent, and none or, where appropriate, one or more members of the signal producing system. The medium is next contacted with a portion of a solid bibulous element to which is bound one of the members of the specific binding pair to allow the medium to traverse such element (immunochromatography). The solid bibulous element is contacted with any remaining members of the signal producing system. Signal resulting from the signal producing system is detected and is related to the amount of the analyte in the sample.

Abstract: Homogeneous assay for determining thyroid binding capacity by use of a fluorescent T.sub.3 tracer, such as T.sub.3 coupled to a fluorescein dye through a radical derived from L-lysine.

Abstract: An immunoassay method for detection of antigen is disclosed. The method employs complement mediated lysis of vesicles loaded with In-111 or other gamma-emitting cation, and quantitative detection of the lysis by gamma-ray perturbed angular correlation (PAC) spectroscopy. The vesicles are labeled with a substance competitive to the antigen to be measured, and the concentration of the antigen in the sample measured by assessing the diminution in lysis due to the presence of the competing antigen.The method may also be used to assess the immunologic competence of a subject by injecting suitably sensitized vesicles and monitoring the in vivo lysis pattern by (PAC).

Abstract: A biologically active latex conjugate prepared by the acidification of latex particles of a core/shell polymer having acetal groups in the shell, whereby said acetal groups are converted to aldehyde groups, and then bonding a biologically active substance having an amino group to said aldehyde groups by reductive amination.

Abstract: The disclosed methods improve conventional agglutination processes for assaying immunoreactive and like substances, primarily by improving the measurement of the agglutination itself. Suspensions containing agglutinated particles are automatically inspected, preferably intermittently during the agglutinating reaction, and the resulting data are processed to identify individual particle aggregates of a selected limited class, which may, for example, comprise aggregates having sizes within a limited size interval. The numbers of such aggregates are compared with corresponding reference values obtained with standard solutions and suitable controls to evaluate the concentration of one of the reactive substances, or other information. The aggregate size intervals and other parameters which are used to define aggregate classes are preferably selected with attention to the detailed behavior of each test system.

Abstract: A highly sensitive and rapid method for quantitatively assaying analytes in liquid media by directly measuring changes in particle size distribution of reagent particles having analyte insolubilized thereon in a system undergoing antibody-induced aggregation has been developed. The amount of analyte initially present can be determined by measuring the change in the distribution of particle size with time, the concentration of a particular size particle at a given time, the rate of formation of a particular size particle, or the steady-state maximum concentration for a particular size particle.

Abstract: A layer of bioactive molecules is coated on a dielectric substrate and is contacted with a solution to be analyzed containing a complex conjugate of said molecule. The rate of complexion of said conjugate moiety with the layer which is a function of its concentration in the analyte is measured by optical means and correlated with corresponding rates obtained from standard reference measurements, thus providing data for determining the unknown concentration of said conjugate moiety in the solution to be analyzed.

Abstract: A method of determining the presence of abnormal immunoglobulin levels in animal body fluids involves (a) forming a reaction mixture of a body fluid and an effective amount of an appropriate aldehyde; (b) timing the rate of reaction of the aldehyde to gel formation; and (c) comparing the rate of reaction of the reaction mixture to a known rate of reaction of a known mixture of the same aldehyde and body fluid containing a known quantity of an immunoglobulin.

Abstract: A process for the detection and for the determination of immunocomplexes in liquids is described. It is based on determining the rate at which the immunoglobulin or the antigen present in the complex reacts with an appropriate immuno-partner, and relating this rate to the rate at which this immunoglobulin or antigen reacts with the corresponding immuno-partner in an immunocomplex-free liquid.

Abstract: Method and apparatus for the measurement of properties of a liquid present in a vessel (2), for example for the measurement of the absorbance of a liquid, of the properties of an agglutination, precipitate (4) or any other reaction result placed on the bottom of a vessel, by means of radiation and of a detector (3) receiving radiation while the vessel moves along with a rotor revolving around the vertical axis (15) of a centrifuge. Thereby the beam of measurement (5) coming from the source of radiation (1) passes substantially horizontally and the intensity of the radiation passing through, or reflected from, the contents of the vessel is measured.