Abstract: Test carrier for analysis of a sample liquid with the help of a specific binding reaction of two bioaffine binding partners, one of which is contained in the sample and one in the reagent system of the test carrier, with several capillary-active test zones (11-16; 21-25) arranged substantially next to one another on a base layer (2). The test zones are in liquid contact with one another so that they form a liquid transport path (20, 30) along which a liquid flows, driven by capillary forces, from a start zone (11, 21), a reaction thereby taking place between the first binding partner and the reagent system containing the second reaction partner, which reaction leads to a labelled species characteristic for the desired analysis.

Abstract: A novel material and device useful in solid-phase binding assays to determine the presence or amount of an analyte in a test sample, particularly antigens, antibodies, or other ligands or DNA segments. The material and device comprises a reaction site having procedural controls and an analyte binding area capable of being simultaneously contacted by the sample and reagent used in the performance of the assay. The procedural controls and analyte binding areas operate to provide readable results as to the presence or absence of analyte and simultaneously verify the assay procedure and therefore the assay result.

Abstract: Certain phenalenimine fluorescent compounds represented by the structure ##STR1## wherein R' and R" are independently hydrogen, alkyl, cycloalkyl, aryl or a heterocycle, or R' comprises the carbon and heteroatoms which form a fused ring with the compound nucleus, are useful in biomedical and analytical determinations. These compounds can be used for staining cells, as well as for the determination of various analytes found in human or animal biological fluids. Such determinations can be carried out in solution or by using dry analytical elements. The fluorescent compounds can be reacted with quinone nuclei to form reducible compounds which are also useful in analytical methods. In addition, the compounds can be incorporated into what are known as "loadable" latex particles to form detectable labels and biological reagents.

Abstract: An analytical element has a peroxidase-labeled ligand analog distributed within a water-soluble binder composition comprising at least about 50 percent, by weight, of poly(vinyl alcohol). As a result, the peroxidase retains more of its stability prior to use. Such elements can be used to determine any of a number of immunologically reactive analytes, such as digoxin.

Abstract: Hydrogen peroxide stabilized in the presence of blood components by the addition of a metal oxide oxidant, an anionic chelating agent, particularly hydroxylic carboxylate and nitroprusside, and a catalase inhibitor. The composition finds particular application for stabilizing hydrogen peroxide in a diagnostic assay on a bibulous support.

Abstract: Described here are procedures and kits for the selective detection of toxicants in environmental samples. Specifically exemplified are procedures and kits which are used to detect heavy metals. The presence of heavy metals is detected by observing the inhibition by the toxicant of a microbially produced enzyme.

Abstract: A culture medium device in the form of a sheet comprises a base sheet member composed of an upper sheet having a hydrophilic property such as filter paper, a lower sheet having a water repellent property covering a lower surface of the upper hydrophilic sheet and a sheet member having a water repellent property preferably in the form of a film having a character suitable for bacteria to be treated. A gel agent or gelatinizer containing bacteria culturing nutrient is dispersed on an upper surface of the upper hydrophilic sheet of the base sheet member and the gel agent or gelatinizer is absorbed in the upper hydrophilic sheet and then solidified. The upper water repellent sheet member is applied so as to cover the upper surface of the upper hydrophilic sheet of the base sheet member.

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: A device for determining HDL cholesterol by obtaining plasma from whole blood and determining the HDL cholesterol level from the plasma. The device includes an inert substrate support or an active substrate support (e.g. one or the other layers), a physical transport medium, a microporous plasma separation membrane connected to the physical transport medium, at least one plasma collecting test membrane, a filtering membrane, LDL and VLDL reactants to form LDL and VLDL precipitates and an optional carrier precipitation membrane. The plasma collecting test membrane has reactants which will react with HDL cholesterol and indicate the HDL cholesterol level quantitatively. The filtering membrane may be located between the microporous plasma separation membrane and the transport medium or between the microporous plasma membrane and the plasma collecting test membrane and its function is to block the precipitated particles from reaching the test zone.

Abstract: The deazauracil containing probes of the invention are able to withstand higher temperatures, thereby allowing unmatched probes and mismatched probes to be washed off at higher hybridization stringency, thereby eliminating background readings and improving ease and accuracy of probe use.

Abstract: Single or multiple blood plasma component concentrations are measured by a disposable stick having one or more blood plasma component reactive areas covered by a semipermeable membrane which is permeable by blood plasma or serum components and impermeable by blood cellular and particulate matter. A second overlay may be superposed with the semipermeable membrane over the reactive areas to receive a blood sample and meter and distribute that sample uniformly to the semipermeable membrane which in turn passes the plasma components uniformly to the reactive areas. The overlays are subsequently separable from the reactive area to remove the cellular components and particulate matter and expose the reactive areas for inspection by, for example, color comparison to standardized charts.

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: Oxygen-independent methods, systems and devices for the enzymatic colorimetric assay and detection of biochemical analytes. Two systems are described, both of which produce less than one equivalent of dye per equivalent of substrate, maintaining dye concentrations in the range where Beer's law predicts a linear color-concentration relationship. One system produces an analog color signal from an analog analyte input, the other system produces a digital color signal from an analog analyte input.

Abstract: General classes of 2-thiazolyl tetrazolium salt compounds have been found to be characterized by a reflectance spectrum exhibiting an extended plateau above about 600-650 nm. Such compounds are useful as chromogenic indicators for reducing substances such as NADH. The reflectance plateau confers improved accuracy to analytical assays, particularly for the determination of analytes of medical diagnostic significance, in which a colorimetric response on a reagent carrier matrix is measured by reflectance.

Abstract: A test device and method of determining the presence and concentration of proteins, including albumin and Bence Jones proteins, in a test sample are disclosed. The test device includes a test pad comprising a new and improved carrier matrix incorporating an indicator reagent composition capable of interacting with proteins to produce a visually or instrumentally detectable and/or measurable response. The new and improved carrier matrix of the test pad comprises a fibrous, bibulous substrate, such as filter paper, homogeneously impregnated with a polymerized urethane-based compound dispersed in a liquid vehicle comprising an aprotic solvent and an alcohol. The resulting non-greening carrier matrix provides improved color resolution and increased sensitivity to proteins in dry phase test strip assays, thereby affording a more accurate and trustworthy protein assay of liquid test samples, such as urine.

Abstract: A dry multilayer analysis element which allows easy permeation of a high molecular weight component or hydrophobic component, which has, in order, at least a water permeable porous reagent layer, a water permeable light reflecting/screen layer, and a water permeable porous spreading layer on a water-impermeable transparent support, a reagent composition capable of producing an optically detectable substance in the presence of a component to be detected being incorporated in at least one of the water-permeable layers including said reagent layer, said light reflecting/screen layer being porous and comprised microcapsules having a core containing light reflective/screen grains and a shell made of a high molecular weight compound, wherein each of said reagent layer, spreading layer, and reflecting/screen layer allows permeation of a high molecular weight or hydrophobic component therethrough.

Abstract: A carrier fleece is prepared for use as reagent carrier from which reagents can be dissolved in as assay such as immunological analysis. The carrier fleece contains from 5 to 60% by weight of cellulose-containing fibers, from 40 to 95% by weight of polyester or polyamide polymer fibers or a combination thereof and from 5 to 30% by weight of the fibers of an organic binding agent which has a hydroxyl or an ester group or a combination thereof. In an immunological analysis, the carrier fleece is impregnated with an immunologically active agent such as a beta-galactosidase conjugate and then introduced into a solution of a sample containing an immunologically active substance to be analyzed. The immunologically active agent is eluted into the sample solution and the presence of the immunologically active substance in the sample is determined.

Abstract: An assay technique for qualitative and quantitative detection of a chemical, biochemical or biological detection of a chemical, biochemical or biological species in sample. The technique comprises: (a) coating at least a predetermined part of a pre-formed surface on a substrate with a thin film of a material capable of binding the species to be assayed, the pre-formed surface being optically active with respect to radiation at least over a predetermined band of wavelengths; (b) contacting the coated surface with sample; and (c) observing the optical properties of said pre-formed surface in order to determine a qualitative and quantitative change in optical properties as a result of the binding of the species onto said thin film of material. The optical properties as a result of the pre-formed surface may be observed before and after step (b) in order to determine any change in optical properties, or they may be monitored during step (b). The pre-formed surface is preferably a grating.

Abstract: A method for the multiplex sequencing on DNA is disclosed which comprises the electroblotting or specific base terminated DNA fragments, which have been resolved by gel electrophoresis, onto the surface of a neutral non-aromatic polymeric microporous membrane exhibiting low background fluorescence which has been surface modified to contain amino groups. Polypropylene membranes are preferably and the introduction of amino groups is accomplished by subjecting the membrane to radio or microwave frequency plasma discharge in the presence of an aminating agent, preferably ammonia. The membrane, containing physically adsorbed DNA fragments on its surface after the electroblotting, is then treated with crosslinking means such as UV radiation or a glutaraldehyde spray to chemically bind the DNA fragments to the membrane through said smino groups contained on the surface thereof.

Abstract: This invention pertains to an improved method for detecting a nucleic acid target sequence with a replicatable RNA reporter system. Two polymerase-mediated reactions are used to generate a target-specific gene containing a DNA sequence for a replicatable RNA. Transcription of the target-specific gene yields a replicatable RNA which is amplified by replication. Synthesis of the gene and the replicatable RNA is strictly dependent upon specific interaction with the target sequence. Consequently, the amplified signal (RNA) is target-dependent and background signal is reduced.

Abstract: A test carrier for the analytical determination of a component of a liquid sample, especially for the diagnosis of diseases, by means of a reaction sequence taking place on the test carrier with several test layers, which, in the initial state, are dry and, in the case of using the sample liquid, are wetted, comprising a base layer on which are present next to one another a sample application region and an evaluation region, a liquid transport path which extends from the sample application region into the evaluation region and a color-forming layer in which, on the basis of a color-formation reaction with the help of a color-forming reagent system, at least one color-forming reagent of which is present in the color-forming layer, there takes place an optically detectable change characteristic for the component to be determined.

Abstract: Certain water-compatible reducible compounds are useful in analytical compositions and elements for assay of various analytes, e.g. microorganisms. These compounds comprise a moiety which provides a detectable species (e.g. a dye) when released from the compound at physiological pH. Further, these compounds are aromatic derivatives or quinones having water-compatibilizing substituents which allow them to be used in compositions without the use of surfactants.

Abstract: Disclosed are devices and methods for interrupting capillary flow of a liquid between two pieces of bibulous material which, prior to actuation, are in a capillary flow relationship to each other. In particular, the capillary flow relationship of two pieces of bibulous material is interrupted by utilizing a liquid expandable piece of bibulous material.

Abstract: On a carrier layer there are arranged several test layers which are at least partly in fluid contact with one another, enabling liquid exchange. On the carrier layer are arranged an application zone, a detection zone for the production of a detectable signal characteristic of the analytical determination, which contains at least one said test layer which is a reaction layer, and an absorption zone with a test layer which is an absorptive layer of an absorbent material, wherein the reaction layer and absorption zone are positioned next to each other. Between the application and the absorption zone is a capillary-active transport path on the carrier layer which connects the application zone and the absorption zone. The reaction layer is arranged parallel to the transport path between the application zone and the absorption zone in such a manner that it is in liquid contact with a liquid transported in the transport path.

Abstract: A method and specimen slide for obtaining fecal occult blood specimens. The slide includes first and second portions each including front and back panels. The first portion includes one or more apertures formed through its front panel which exposes a reagent-carrying sheet and the back panel of the first portion includes a flap that may be opened for the application of additional reagents to the back of the sheet. The second portion includes an aperture in its front panel and a flap formed in its back panel. A sheet is carried between the front and back panels of the second portion onto which a fecal specimen may be smeared. The sheet includes pre-perforated removable portions that may be easily accessed through the flap. As an alternative embodiment, the back panel of the second portion may include a removable tab to which is fixed the specimen sheet. The tab and specimen sheet may be removed for easy access to the removable portions of the specimen sheet.

Abstract: Packages which are subject to tampering while in a store or deterioration over time due to the presence of oxygen may be readily identified by placing therein a multi-component visual indicator system which is sensitive to the presence of oxygen. The system, which may be prepared aerobically and then placed into an anaerobic environment for use, is not effected by the presence of reducing agents found commonly in foods, drugs, and cosmetics.

Abstract: A diagnostic test slide for performing diagnostic tests for detecting the presence of microogranisms, enzymes or metabolites comprising a plastic film having a coating therein comprising a carrier and a reagent. The coated film is placed in a mount that is constructed and arranged to form a border around a portion of the film. A method is provided for making the test slide utilizing conventional, automated devices for making coated photographic films, and conventional, automated devices for mounting slide film in mounts.

Abstract: A test device and method of determining the presence and concentration of proteins in a test sample are disclosed. The test device includes a test pad comprising a new and improved carrier matrix incorporating an indicator reagent composition capable of interacting with proteins to produce a detectable or measurable response. The new and improved carrier matrix of the test pad comprises a film, membrane or layer of a polymerized urethane-based compound, a water insoluble inorganic compound and an insoluble organic compound. The carrier matrix provides improved color resolution and increased sensitivity to proteins in dry phase test strip assays, thereby achieving an accurate and trustworthy protein assay of a liquid test sample, such as urine, having a protein concentration as low as about 5 mg/dL. Also disclosed is a method of making the test device.

Abstract: A rapid and sensitive assay method for the detection of IgM antibody or the simultaneous detection of IgG and IgM antibody to retroviruses, including HIV-1 and HIV-2, and diagnostic test kits for carrying out the method is provided. According to the method of the invention, results are obtainable within 70 minutes.

Abstract: A device useful for growing aerobic microorganisms, particularly molds. The device employs a relatively small amount of water-reconstitutable medium that can be sealed in order to prevent desiccation and contamination of the medium yet still provide an adequate supply of air to the medium, by the use of a membrane underlying the medium, to support the growth of aerobic microorganisms.

Abstract: Methods and compositions are provided for assays involving members of a specific binding pair ("sbp members") and members of a signal producing system ("sps members"). The signal producing system is capable of producing a detectible signal in relation to the presence or amount of an analyte in a sample suspected of containing the analyte. Exemplary of sps members are enzymes and enzyme substrates, which react with each other to produce a signal. The improvement of the present invention comprises temporarily delaying the production of the signal without subsequent reagent addition. The delay can be achieved by employing an inhibitor which can be an alternate substrate for the enzyme or a compound which reacts with the product of the enzyme and its substrate in an effective amount.

Abstract: This invention is directed to a ligand-receptor assay for determining the presence or amount of at least one target ligand, capable of competing with a ligand analogue conjugate for binding sites available on a ligand receptor, said ligand analogue conjugate comprising at least one ligand analogue coupled to a signal development element capable of emitting a detectable signal, in a fluid sample suspected of containing said target ligand, comprising the steps of:a. contacting said fluid sample with ligand analogue conjugate and ligand receptor to form a reaction mixture, the relative amounts of ligand analogue conjugate and ligand receptor being such that in the absence of target ligand, and subsequent to substantially equilibrium binding, substantially all of the ligand analogue conjugate is bound to ligand receptor;b. detecting the unbound ligand analogue conjugate;c. relating the detectable signal to the presence or amount of target ligand in the fluid sample.

Abstract: A new and improved test device and method of determining the presence or concentration of a peroxidatively active substance, such as hemoglobin, in a test sample are disclosed. The test device includes a test pad comprising a suitable carrier matrix incorporating an indicator reagent composition capable of interacting with a perioxidatively active substance to produce a detectable or measurable response. In addition, a new and improved indicator reagent composition, comprising an indicator dye, such as a redox indicator, like a benzidine indicator; a hydroperoxide; an amine borate compound having the general structural formula: ##STR1## wherein R.sub.1, R.sub.2, and R.sub.3 are, independently, methyl groups or ethyl groups, and m, n and p are numerals ranging from one to about three; a buffer, is incorporated into a suitable carrier matrix to provide a more accurate and trustworthy assay of a test sample for a peroxidatively active substance.

Abstract: A diagnostic kit is disclosed for the detection of hemoglobin, myoglobin, ferritin, or the like substances having peroxidase-like activity in different mixtures of biological origin, such as fecal blood in toilet bowl, occult blood in the breath of internally bleeding horses, or myoglobin in the urine of severely muscle damaged victims. The kit includes, in an air, moisture, and light proof package, an inert water insoluble matrix, such as a sheet of paper, which has an area where a chemical composition containing a water soluble polymer, or polymers, is deposited in at least two separate steps of thin film coating, for the detection of the above substances. The composition further includes one or more oxygen donors, one or more organic peroxides or other suitable oxidizing agents, and a leuco-dye which gives a colored oxidation product when it is oxidized by the oxidizing agents with the hemoglobin or like substance acting as the catalyst.

Abstract: A test for microbial growth is carried out by culturing a microorgnism to be tested in a lliquid culture medium containing an enzymatically hydrolyzable fluorogenic substrate for a period of less than about 7 hours, measuring fluorescence of the culture medium resulting from hydrolysis of the fluorogenic substrate by growth of the microorganism, continuing culturing of the microorganism in the culture medium for an additional period, and measuring microorganism growth by a non-fluorescent method as a confirmatory test of growth determined from fluorescence. Preferably, the additional culture period is overnight and the non-fluorescent method is by visual inspection. The culture medium may be in the wall of a microtitre plate, and the culture medium can contain an antibiotic to test for sensitivity of a microorganism to the antibiotic or to test for minimum inhibitory concentration of the antibiotic.

Abstract: A new class of peroxidase substrates consists of o-diaminobenzenes having a substituent in the 4 position. The new substrates may be used in immunoassays in which a peroxidase is the label, or in assays for the peroxidase itself. Immunoassays using other enzyme labels which cause formation of hydrogen peroxide may be followed using the substrate of the invention by adding the substrate and a peroxidase to the assay fluid and detecting color formed as a result of oxidation of the substrate by the formed peroxide.

Abstract: A semi-automated biological sample analyzer and subsystems are provided to simultaneously perform a plurality of enzyme immuno assays for human IgE class antibodies specific to a panel of preselected allergens in each of a plurality of biological samples. A carousel is provided to position and hold a plurality of reaction cartridges. Each reaction cartridge includes a plurality of isolated test sites formed in a two dimensional array in a solid phase binding layer contained within a reaction well which is adapted to contain a biological sample to be assayed. The carousel and cartridges contain structures which cooperate to precisely position the cartridges in each of three separate dimensions so that each cartridge is positioned uniformly. An optical reader operating on a principle of diffuse reflectance is provided to read the results of the assays from each test site of each cartridge.

Abstract: A method and apparatus for the quantitative determination of an analyte in a liquid employs a liquid-permeable solid medium defining a liquid flow path. The medium includes a number of reaction-containing reaction zones spaced apart along the flow path and in which reaction occurs with the analyte or an analyte derivative (e.g., a labeled analyte) to result in the formation of a predetermined product. Detector means are employed to detect analyte, analyte derivatives, reactant or predetermined product in the reaction zones, the number of such zones in which such detection occurs indicating the amount of analyte in the liquid.

Abstract: The test paper for urinalysis of the present invention is made up of water-soluble paper which consists of 99-45 weight per cent of carboxymethyl cellulose and 1-55 weight per cent of wood pulp. This water-soluble paper is covered or impregnated with one or more reagents needed for urinalysis in order to form an appropriate shape of spots. The urinary test paper of the present invention can be flushed down a toilet bowl or a urinal in a flush toilet after use thereof.

Abstract: A device for carrying out extemporaneous quantitative diagnostic tests on the whole blood which comprises:a) a rigid plastic strip, to the end of which there is cemented a substrate containing a reactive substance which undergoes a selective color reaction respectively with the substance to be determined in the blood, anda visual colorimetric reference scale specific for each of the examined substances and possibly corrected so as to directly read the content of the examined substance in the plasma from the test carried out the whole blood.

Abstract: A dry-type analytical element suitable for measuring the activity of alanine aminotransferase in a liquid sample, characterized by incorporating a dye capable of absorbing the electromagnetic waves of 400 to 500 nm into at least one water-permeable layer. The coloring sensitivity of the dry-type analytical element does not increase substantially even under a fluorescent light, and thereby, an accurate measured value can easily be obtained.

Abstract: The specification discloses a fecal occult blood test device capable of determining whether the blood found during the test originated in the upper or lower gastrointestinal track. A fecal sample is applied to a test medium charged to be differentially attractive to blood components originating in the upper and lower gastrointestinal track respectively. A solvent is applied to the test specimen to cause differential migration of the blood components and an indicator is then applied to indicate the presence of the blood components, if any.

Abstract: A stable dry multi-layer analytical element for enzyme or triglyceride analysis in a fluid sample is prepared containing first and second layers on a support. The first layer contains a tetrazolium salt as a dye forming precursor. The second layer is adjacent the first layer and contains an electron-transmitting agent. Either layer contains a co-enzyme in oxidized form and either layer contains a reagent containing an enzyme substrate, enzyme or co-enzyme other than the oxidized co-enzyme. The analytical element has improved storage stability and low fog density before and after storage.

Abstract: The present invention provides a dry reagent for blood coagulation tests in which an at least partial course of the coagulation cascade takes place, comprising a carrier material which contains a chromophoric substrate of a protease of the blood coagulation system, at least one factor and/or co-factor of the blood coagulation system and a buffer.

Abstract: The present invention relates to diagnostic methods for detecting or evaluating the presence of periodontal diseases, especially gingivitis, in humans or lower animals by measuring the presence of leukocyte esterase. These diagnostic methods comprise measuring the amount of leukocyte esterase present in the oral cavity of the human or lower aniaml being diagnosed.The present invention further relates to diagnostic products useful in vivo for detecting or evaluating the presence of periodontal diseases, especially gingivitis, in humans. These diagnostic products contain at least one agent useful in detecting the presence of leukocyte esterase, and a carrier material. These diagnostic products must be sterile and safe for in vivo contact with the tissue in the oral cavity of the human being diagnosed.Finally, the present invention further relates to diagnostic kits useful for detecting or evaluating the presence of periodontal diseases, especially gingivitis, in humans.

Abstract: An in situ method of determining the quality of a medium capable of suppong cellular growth comprises obtaining viable cells which are anchored to a substrate, determining the value of at least one characteristic of the cell which is proportional by a factor to the number of the cells present under conditions which preserve cell viability, calculating the number of cells present by multiplying the value of the characteristic by the factor, exposing the cells to the medium by in situ immersing the substrate with the anchored cells in the medium for a period of time and under conditions which preserve the viability of the cells and permit cell growth, withdrawiing the cells from the medium, repeating the steps for determining the value of the characteristic of the cells and for calculating the number of cells present, calculating the cell growth rate or the variation in the number of anchored cells per unit of time during the period of time from the formula cell variation/t=(N-N.sub.

Abstract: A method for determining the presence of an analyte in a fluid is described along with various components of an apparatus specifically designed to carry out the method. The method involves taking a reflectance reading from one surface of an inert porous matrix impregnated with a reagent that will interact with the analyte to produce a light-absorbing reaction product when the fluid being analyzed is applied to another surface and migrates through the matrix to the surface being read. Reflectance measurements are made at two separate wavelengths in order to eliminate interferences, and a timing circuit is triggered by an initial decrease in reflectance by the wetting of the surface whose reflectance is being measured by the fluid which passes through the inert matrix. The method and apparatus are particularly suitable for the measurement of glucose levels in blood without requiring separation of red blood cells from serum or plasma.

Abstract: A method for measuring creatine in a sample by the use of creatine amidinohydrolase which comprises decomposing the N-ethylglycine present in the sample enzymatically and thereafter reacting sarcosine oxidase upon the sample; and a reagent for use in the measurement of creatine comprising the first reagent and the second reagent, wherein the first reagent comprises a sarcosine oxidase of which Km value to N-ethylglycine at pH 8, 37.degree. C. is 20 mM or below and catalase or comprises said sarcosine oxidase, a hydrogen donor oxidatively condensable with 4-aminoantipyrine and peroxidase and the second reagent comprises creatine amidinohydrolase, a sarcosin oxidase of which Km value to N-ethylglycine at pH 8, 37.degree. C. is 50 mM or above, peroxidase and a color reagent for H.sub.2 O.sub.2.

Abstract: An assay system useful for the determination of NAD(P)H, NAD(P), or a substrate of an enzyme which reacts with the formation or comsumption of NAD(P)H. Concentrations of organic substrates for example alcohol, cholesterol, uric acid, in a biological fluid such as saliva, blood or urine may be determined. The system includes a diaphorase which catalyzes a NAD(P)H-dependent reduction of a chromogen to cause a visible color change; this color change is indicative of the concentration sought to be determined. The system includes a chromogen which is a first substrate for the diaphorase which causes a color change when reduced by NAD(P)H, and a second substrate which is a competing substrate for the diaphorase; the competing substrate is irreversibly reduced by the diaphorase. The system is capable of measuring colorimetrically without dilution concentrations of organic compounds in biological fluids which previously could not be measured in such concentration.

Abstract: A method for determining the presence of a predetermined minimum detectible amount of one or more analytes in a sample suspected of containing the analyte is disclosed. Each analyte is a member of a specific binding pair ("sbp member") consisting of ligand and its complementary receptor. The method comprises contacting with a test solution containing the sample and predetermined amounts of two or more of a plurality of first sbp members, each respectively analogous to one of the analytes, a contact portion of a piece of bibulous material capable of being traversed in at least one direction by the test solution by capillary migration. The bibulous material contains predetermined amounts of two or more of a plurality of second sbp members, each respectively capable of binding one of the analytes and corresponding first sbp member.