Abstract: An integral multilayer analytical element which comprises a water-impermeable light-transmissive support, a hydrophilic layer containing a water-absorptive hydrophilic polymer binder and a spreading layer superposed in this order, and contains at least one reagent capable of reacting with a component of a sample to produce a detectable species capable of detecting by light, which is characterized in that light-scattering particulates in an amount to make light transmittance to 10 to 2.5% are contained in the above hydrophilic layer and/or a layer located on the side of the support therefrom. This element may decrease the influence of a conventional reagent layer up to the extent being negligible without lowering the sensitivity. Precision of the measurement at a low concentration range is also high, and reproducibility of the meaurement is well. Manufacture of this element is easy.

Abstract: The interference of dehydroascorbic acid, an oxidation product of ascorbic acid, in analytical methods is reduced with the use of certain nitrogen-containing organic buffers. Dehydroascorbic acid tends to cause premature reduction of reducible compounds which are used to provide detectable species in the presence of an analyte. These organic buffers, as opposed to inorganic buffers, prevent premature reduction of the reducible compounds. An analytical method can be carried out in solution or in a dry analytical element.

Abstract: Disclosed herein is an assay useful for the quantitative determination of hemoglobin in whole blood. This assay utilizes a multizone element comprising a registration zone comprising particulate barium sulfate distributed in a "blush" polymer, and a spreading zone having a void volume and an average pore size (e.g. greater than 5 microns) effective to accommodate whole blood. The element also contains an interactive composition capable of converting substantially all forms of hemoglobin into a detectable end product. One particularly useful interactive composition comprises a hemoglobin oxidizing agent (e.g. ferricyanide) and thiocyanate. Another useful interactive composition comprises an ionic surfactant, e.g. sodium octyl sulfate or sodium dodecyl sulfate.

Abstract: A method for quantitative determination of bilirubin is disclosed. The method comprises bringing a bilirubin-containing aqueous liquid sample into contact with a hydrophobic bilirubin extracting composition containing a hydrophobic amine capable of extracting bilirubin. The amine extracts the bilirubin in said aqueous liquid sample. Photometry is then used to determine the concentration of bilirubin extracted with the bilirubin extracting composition. A device for use in this method is also disclosed. The device has a layer containing a hydrophobic bilirubin extracting composition containing a hydrophobic amine capable of extracting bilirubin.

Abstract: A method of preparing an integral multilayer analytical element such as for analysis of calcium comprising a water-impermeable light-transmissive support, a reagent layer containing a water-soluble indicator capable of reacting with an analyte to produce an optically detectable change, and a porous spreading layer containing a spreading action controller and/or an acid capable of decomposing the calcium compounds in a sample, superposed in this order, wherein the spreading action controller and/or the acid is dissolved in an organic solvent which does not dissolve the above water-soluble indicator, this solution is incorporated into the porous spreading layer, and this superposed material is dried. In the method of the present invention, the migration of the water-soluble indicator in the reagent layer at the time of incorporating the spreading action controller or the acid into the spreading layer is inhibited by using a particular organic solvent.

Abstract: A dry type multilayer analysis element comprises at least one porous medium layer comprising a membrane filter, to which an antigen (or antibody) is immobilized, and at least one reagent layer through which a substance(s) which did not participate in an antigen-antibody reaction can permeate.The multilayer analysis element is effective for assaying components present in body fluids, blood, urine, etc., in a simple manner.

Abstract: The present invention provides an analysis element for the determination of coagulation parameters with the help of a detectable or a detection reaction-initiating substrate of a protease of the blood coagulation system and at least one factor and/or co-factor of the blood coagulation system and a buffer substance, wherein the factor and/or co-factor, together with a water-soluble, non-ionic polymer which does not falsely influence the course of the coagulation cascade, is impregnated on an open, planar composite structure which consists of a material which does not have a disturbing influence on the course of the coagulation.

Abstract: A member of an analytical element for the analysis of a liquid sample containing solid material, comprising a volume filtration layer composed of a fibrous material and a spreading layer having a liquid-retaining capacity larger than that of the volume filtration layer, in which the volume filtration layer and the spreading layer are united to give an integrated structure. The spreading layer may be composed of a fibrous material, a woven cloth, a knitted cloth or a non-fibrous porous medium.

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 inpermeable by blood cellular and particulate matter. A second overlap 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: The present invention provides a test carrier (1) for the analytical determination of a component of a body fluid with a base layer (2) and at least two planar test layers which, in the initial state of the test carrier, before carrying out the determination, are separate from one another but can be brought into contact with one another by external manipulation, wherein a first test layer (8) and a second test layer (10) are arranged on the base layer essentially next to one another but separated in the initial state by a gap, a contact element (11, 17, 18, 20) being provided which consists of a capillary-active material which is so dimensioned that it can bridge the gap (12) and which is so mounted and arranged that, in a first position, it cannot contact at least one of the test layers (8, 10) but, by external pressure, it can be brought into a second position in which it contacts both test layers in such a manner that a liquid exchange between the test layers is possible.

Abstract: Apparatuses and methods are disclosed which can be used in the field (i.e., outside the laboratory environment) to determine qualitatively and at least semiquantitatively the presence or absence of minute quantities of ligand. The apparatus can be in the form of a strip comprising a support means provided with a groove intermediate its ends forming a crease line upon which the strip can be folded upon itself with bibulous elements and spaced from the crease line and arranged so that when the strip is folded upon itself the bibulous elements become aligned with each other and come into liquid contact.

Abstract: A transparent reagent carrier layers in analytical agents for dry chemical detection of constituents of aqueous sample solutions, the reagent carrier layer consisting of a water-soluble or water-swellable component and a film-forming component.

Abstract: A method for detecting a component of a biological system, which comprises contacting a biological component detecting device composed of a light reflecting substrate (I) substantially free from diffused reflection, a light interference layer (II) formed on the substrate (I), and a layer (III) of a substance for detecting said biological component provided at least in a region on the layer (II), with a solution presumed to contain the biological component to be detected, then forming a light-transmitting reflecting layer (IV) on its surface, and thereafter detecting the color of light interference or the brightness of the reflected light on the surface of the device.

Abstract: A device for separating plasma or serum from whole blood and analyzing the same, wherein the device includes a layer of glass fibers with an average diameter of from 0.2 to 5 microns and having a density of from 0.1 to 0.5 g./cm.sup.3 and an adsorption volume at least twice that of the plasma or serum to be separated and, preferably, more than 3.3 times the volume.

Abstract: A method for detecting basic narcotics or drugs in body fluids which comprises filtering body fluids through a cellulosic filtering means treated with a binding agent for the narcotics or drugs and the filtering means. The binding agent is a polycarboxylic acid. The narcotics or drugs are then treated with a subsequent reagent to produce a color reaction. A device for detecting basic narcotics or drugs in also disclosed which contains the filtering means treated with the binding agent so as to concentrate the narcotic or drug prior to reaction with a suitable indicator.

Abstract: A multilayer analytical element exhibits improved precision in the assay of total lactate dehydrogenase (LDH). The element also provides reduced susceptibility to total protein and hemoglobin interferences in the assay. The element contains a porous spreading layer composed of a particulate structure. A fluorinated surfactant is also used in the assay. This surfactant has one or more fluorocarbon moieties provided, that when the surfactant has more than one such moiety, they are substantially linear. The surfactant can be incorporated in the element or added at the time of the assay.

Abstract: A process for preparing test aids for detecting substances to be analyzed by means of redox reactions containing single component oxidation indicators as the indicator substance in which oxidizable aromatic amine or hydrazino compounds, which are not capable of coupling with themselves, are added as decolorants.

Abstract: A test strip is disclosed which provides for transport and separation of heterogenous fluid samples. This test strip can be used for analysis of whole blood by reflectance measurement. This test strip, which can be especially adapted for use in a disposable blood sampling fixture, comprises two functional components: (1) a wicking element for reception of the whole blood sample and transport of the sample to a dry chemistry reagent system, and (2) a porous membrane which has been impregnated with a dry chemistry reagent system specific for analysis of an analyte within the whole blood sample. A barrier layer is provided between the wicking layer and the porous membrane to preclude contact therebetween. In the preferred embodiments of this invention, an aperture is cut or formed in the barrier layer to allow for the flow of sample for the wick to the surface of the porous membrane.

Abstract: A colorimetric assay for the determination of conjugated, unconjugated or total bilirubin in biological fluids can be carried out with an improved analytical element. This element comprises a support having thereon a substantially gelatin-free mordant layer comprising a positively-charged interactive mordant having at least one binding site for bilirubin, a radiation-blocking layer, and a porous spreading layer. This element does not contain any colorimetric or fluorometric interactive compositions for bilirubin other than the mordant.

Abstract: The present invention provides a test carrier for the determination of coagulation parameters, wherein it includes a test layer which contains silanized glass fibres which are coated with polyvinyl alcohol or polyvinyl alcohol/vinyl acetate.

Abstract: An analytical element for quantitative analysis of analyte contained in a body fluid or the like, which has at least one reagent layer comprising a reactive reagent and a binder, characterized in that a portion or whole of the binder is a polycarboxylic acid carrying a nonionic surface active agent attached through ester linkage to at least a portion of the carboxyl groups contained therein.

Abstract: Hydrophilic glass fibers which have bonded to their surfaces a layer of silane molecules of the formula ##STR1## are useful for the separation of plasma from blood for haemostasiological testing. In the formula: the molecule is bonded at its end oxygen to a surface of a glass fibre; R.sub.1 is C.sub.2 -C.sub.6 alkylene; X is OH, C.sub.1 -C.sub.6 alkoxy, having n carbon atoms and up to (n-1) OH groups in which n is 1-6, or an amino acid or peptide residue; and each of R'.sub.3 and R".sub.3 is C.sub.1 -C.sub.6 alkyl, an oxygen bridge to the silicon atom of another silane molecule or an oxygen bridge to the glass surface. The fibres have an average diameter of from 0.2 to 5 microns and a density of 0.1 to 0.5 g/cm.sup.3.

Abstract: A multilayer chemical analytical element is employable in quantitative analysis of analyte in a biological fluid such as blood. The element consists of a porous spreading layer, a light-blocking layer and a reagent layer on a water-impermeable light-transmissive support in order. The light-blocking layer contains a titanium dioxide fine powder with no provision of aluminum oxide compound or silicon oxide.

Abstract: A composition of a polysaccharide with a detectable material appended thereto and a 1,3-dione having a methylene group between the two carbonyls of the 1,3-dione, which methylene group has at least one ionizable hydrogen, provides accurate results in assays of hydrolyzing enzymes such as amylase. The composition can be incorporated in the reagent zone of a dry test element having a reagent zone and a registration zone.

Abstract: A test vial for the detection of gas components in air, containing a packing changing along the longitudinal axis of the test vial is improved in such a manner that, at a constant flow resistance, a sensitivity for the hazardous substance to be detected is obtained, which varies along the test vial. The provision is made that the packing consists of a combination of applied indicator and carrier substance at ratios varying along the longitudinal axis.

Abstract: A heterogeneous, competitive binding immunoassay for either phenytoin or phenobarbital is conducted with a labeled conjugate comprising a derivative of hydantoin and a label. The hydantoin derivative is 5-ethyl,5-phenyl hydantoin and it is linked to the label (e.g. an enzyme) with a linkage derived from an aliphatic monocarboxylic acid. The immunoassay can be carried out either in solution or with a dry analytical element.

Abstract: An analytical element for the detection of hydrogen peroxide comprising a peroxidase-functional material, a hydrogen donor and a coupler, wherein the peroxidase-functional material and hydrogen donor are arranged so as to be separate from each other, for example in separate layers, but are made interactive by the application of a fluid sample.

Abstract: A method and device for separating blood into fluid and cellular fractions for diagnostic tests. The whole blood is introduced to a carrier containing a layer of carbohydrate which results in the rapid separation of the fluid from the cellular fractions. In a preferred embodiment, the device is fabricated in a sandwich design containing layers of carbohydrate and reagent material between two layers of plastic.

Abstract: A heterogeneous, competitive binding immunoassay is conducted with a dry analytical element. The immunoassay is useful for determining a ligand (e.g. a therapeutic drug) and includes contacting a finite area of the element spreading layer with a sample of a liquid in the presence of a labeled ligand analog and an immobilized receptor. An immobilized ligand-receptor complex is formed within the finite area. Simultaneously, the uncomplexed ligand migrates horizontally away from the immobilized complex which remains in the center of the finite area. At least five seconds after the completion of the contacting, the amount of immobilized complex is measured in the center of the finite area.

Abstract: A particular class of triarylmethane leuco dyes are useful in analytical compositions, elements and methods. These leuco dyes are triarylmethane compounds having an aromatic heterocyclic moiety attached to the central methane carbon and which, upon interaction with hydrogen peroxide, provide dyes having a maximum absorption at a wavelength equal to or greater than about 600 nm. Particularly useful leuco dyes have the structure: ##STR1## wherein R is a 5- to 15-membered aromatic heterocyclic moiety; and R' and R" are independently open chain or cyclic amines. These compounds are useful for providing detectable dyes in compositions and elements useful for detection of hydrogen peroxide or other analytes which react to produce hydrogen peroxide in aqueous liquids, e.g. biological fluids.

Abstract: A test means for determining the presence of an ion in an aqueous test sample, a method for preparing it and a method for using it. The test means comprises a hydrophilic carrier matrix incorporated with finely divided globules of a hydrophobic vehicle. The hydrophobic vehicle contains an ionophore capable of forming a complex with the ion and a reporter substance capable of interacting with the complex of ionophore and ion to produce a detectable response. The test means of this invention is useful for clinical determinations of serum potassium. The test means forms the reagent layer in a multilayer format which is particularly suited to whole blood electrolyte determinations and does not require washing or wiping before use.

Abstract: Disclosed herein is an assay useful for the determination of an analyte in whole blood. In particular, this assay is useful for the quantitative determination of peroxide-generating analytes, such as glucose or cholesterol, in whole blood. This assay utilizes a multizone element consisting essentially of a support having thereon, in order and in fluid contact, a registration zone and a reagent/spreading zone. The reagent/spreading zone has a void volume and average pore size effective to accommodate whole blood, and contains an interactive composition necessary for the analysis. Such composition is capable of providing, upon interaction with the analyte, a dye which can be spectrophotometrically detected at a wavelength greater than about 600 nm.

Abstract: An improved multilayer analytical element for the determination of calcium comprising a liquid impermeable, optically transparent support; at least one reagent layer positioned with a first side on said support and containing at least one reagent capable of reacting with a calcium component in a fluid sample; and at least one porous developing layer on the second side of said reagent layer, said porous developing layer being permeable to calcium from said fluid sample thereby transporting said calcium to said reagent layer. The improvement comprises at least one of said reagent layer and developing layer containing a basic substance of the formula M.sub.v H.sub.w PO.sub.4 .multidot.ZH.sub.

Abstract: There is disclosed an analytical element comprising a support; a reagent layer which is positioned on one side of the support and contains a reagent reactive with a component in a fluid sample; and a porous spreading layer which is positioned on the reagent layer on the opposite side to that of the support for permitting the component in the fluid sample to permeate into the reagent layer; wherein at least one layer contains 5% by weight or more of a polymer formed by, (i) a copolymerizable ethylenically unsaturated acid with (ii) a copolymerizable ethylenically unsaturated monomer.The analytical element according to the present invention can determine a component in a fluid sample quantitatively.

Abstract: A reagent composition, dry analytical element and a method of using same to determine total bilirubin in aqueous liquids are disclosed. The reagent composition comprises a diazonium salt, or reagents capable of producing a diazonium salt when contacted with water, and 3,3-dimethylglutaric acid or a salt thereof present in an amount effective to buffer the composition at a pH of about 3.5 or less when the composition is contacted with a 2 .mu.L sample of pooled human serum. The composition and elements described herein provide a means to eliminate the effect of an undetermined interferent which is either preformed or formed in situ in diazo-based total bilirubin determinations of biological fluids (e.g. uremic serum).

Abstract: An integral multilayer analytical element for the analysis of ammonia or an ammonia forming substrate in a liquid sample is disclosed. The element comprises a transparent support on which an indicator layer for ammonia, a liquid blocking layer, a reagent layer incorporated with a reagent which may react with the substrate to form ammonia, and a spreading layer, are integrally superposed in this order. The improvement is that the liquid blocking layer is made of a porous material which is permeable to ammonia but substantially impermeable to liquids.

Abstract: A multizone analytical element for the determination of an analyte in an aqueous liquid comprises a registration zone and a porous spreading zone to receive and transport the aqueous liquid. The spreading zone contains a nonpolymeric quaternary ammonium compound represented by either of the structures: ##STR1## wherein represents a single or double bond; R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently alkyl; aryl; cycloalkyl; or alkaryl; provided that R.sub.1, R.sub.2, R.sub.3 and R.sub.4 together comprise at least 12 carbon atoms; or R.sub.1 and R.sub.2 taken together with the nitrogen atom, form a quaternary 5- to 16-membered heterocyclic ring; or R.sub.1, R.sub.2 and R.sub.3 taken together with the nitrogen atom, form a quaternary 5- to 16-membered heterocyclic ring; and X.sup.- is a monovalent anion.

Abstract: A dry element capable of use for the analysis or transport of liquids comprises an isotropically porous zone which comprises a blush polymer having dispersed therein a particulate material and a nonpolymeric heterocyclic, aliphatic or carbocyclic quaternary ammonium compound comprising at least 12 carbon atoms therein. This compound is present in the porous zone in an amount of at least about 2 weight percent, based on the dry weight of the blush polymer. The porous zone of this element has improved cohesive strength which improves its resistance to abrasion. The element can be used to determine an analyte in an aqueous liquid, such as biological fluids.

Abstract: A device for the quantitative determination of heparin in mammalian blood plasma, a method for the preparation of such device and a method for determining the plasma's heparin concentration using the device. The device, which is prepared using a freeze-drying technique, comprises a first upper layer of a carrier matrix material containing a buffer, AT-III and thrombin and a second, lower layer of a carrier matrix containing a thrombin sensitive fluorogenic or chromogenic substrate being capable of interacting with thrombin in such a manner that a time-related chemical change detectable by fluorometric or spectrophotometric means takes place when thrombin and the substrate are contacted in a suitable liquid environment.

Abstract: A test device for determining the presence of a substance in a test sample is disclosed, as well as methods for making and using it. The device comprises a support member having a reagent layer affixed to it which contains a reagent system which produces a detectable response in the presence of the analyte. The reagent layer has an upper layer affixed to the side opposite the support member. The upper layer comprises a polymer which is at least partially crosslinked.The method of use comprises contacting the device with the test sample, wiping the upper layer free of test sample residue, and observing a detectable response.

Abstract: In a method for assaying an analyte comprising applying a liquid sample containing an analyte to a spreading layer of a multilayer analysis element comprising a support having laminated thereon at least one reagent layer containing a substrate capable of converting a detectable chemical species upon reaction with the analyte and a liquid sample-spreading layer and then detecting the chemical species, a wetting liquid is applied onto the spreading layer, prior to applying the liquid sample to the spreading layer. A liquid sample having a high analyte content can be measured with high accuracy.

Abstract: A process for rapidly differentiating between gram-positive and gram-negative microorganisms by mixing an anionic surfactant to inhibit the reduction capability of the gram-positive microorganisms, an electron transfer agent and a compound capable of being reduced to a detectable species by both gram-positive and gram-negative microorganisms in the absence of an anionic surfactant.

Abstract: An analytical element comprising a light-transmissive and liquid-impervious support, at least one reagent layer containing at least one reagent which reacts with a component in a fluid sample and at least one development layer provided at a position on the reagent layer on the opposite side to that of the support for permitting the component in said fluid sample to permeate into the reagent layer, at least one layer of reagent layers being constituted of polymeric particulate units each having a core-shell multi-layer structure comprising a core, which is hydrophobic and substantially unswellable with a fluid sample, and a hydrophilic outer shell.

Abstract: A quantitative analysis film comprising a reagent layer comprising a cationic dye-forming color indicator for detecting hydrogen peroxide and an anionic polymer. By the use of such a color indicator and an anionic polymer in combination, a cationic dye is formed; the formed cationic dye is then bound and fixed to the anionic polymer to provide an intensified color. A method for the colorimetric assay of hydrogen peroxide or a precursor thereof with high sensitivity and high efficiency is also disclosed.

Abstract: A multizone element, for quantitative analyte determination in whole blood, containing a porous spreading zone separated from a reagent zone by a barrier zone, said barrier zone comprising a non-porous film comprising a polymer of: from 30 to 95 percent by weight of polymerized monomer having the structure ##STR1## from 0.25 to 30 percent by weight of polymerized monomer having the structure ##STR2## and from 0.1 to 50 percent by weight of polymerized monomer having the structure ##STR3## wherein: R.sup.1, R.sup.3, and R.sup.5 are independently selected from the group consisting of hydrogen and methyl,R.sup.2 is alkyl of from 1 to 16 carbon atoms,R.sup.4 and R.sup.6 are independently selected from the group consisting of alkylene groups having from 1 to 6 carbon atoms, ##STR4## wherein R.sup.7 is hydrogen, alkyl of 1 to 10 carbon atoms, or cycloalkyl of 5 to 10 carbon atoms, andM is NR.sup.8 R.sup.9 H.sup.+ X or SO.sub.3.sup.- X wherein R.sup.8 and R.sup.

Abstract: A composition and process for permitting the separation of plasma or serum from whole blood. The composition includes glass fibers having an average diameter of from 0.2.mu. to 5.mu. and a density of 0.1 g/cm.sup.2 to 0.5 g/cm.sup.2. The process includes the steps of slowly trickling whole blood onto one side of a layer composed of the composition of glass fibers, whereby plasma or serum separated from the blood becomes available at another side of the layer. The total volume of the plasma or serum separated from the blood is limited to at most 50% of the absorption volume of the glass fiber layer.

Abstract: A multilayer element for the analysis of a liquid containing an analyte comprising a reaction layer which retains a predetermined amount of a diffusible reagent containing a detectable species; said reagent adapted to be rendered substantially non-diffusible by said analyte as a function of the concentration of said analyte; a registration layer adapted to receive reagent diffusing thereto; means for detecting said reagent in said registration layer and an insulating layer intermediate said reaction layer adapted to provide discrimination between detectable species in said reagent layer and said registration layer.

Abstract: A direct, spectrophotometric method for determining the total bilirubin content of an aqueous liquid is provided by detecting the absorption spectrum of the aqueous liquid at a wavelength at which the absorption characteristics of unconjugated bilirubin and conjugated bilirubin are effectively identical. The method is carried out, for example, at a wavelength in the range of from about 385 to 425 nm. An interactive mordant for bilirubin is useful in the assay method to increase assay sensitivity. The assay can be performed as a solution assay or with a "dry chemistry" test element, for example, a multilayer analytical test element.

Abstract: A multilayer analytical element for detecting a ligand in or the ligand binding capacity of a liquid sample of the type having a reagent layer incorporating reagents which are responsive to the ligand in or the ligand binding capacity of the sample to give a detectable response, a radiation diffusing and blocking layer, and a support layer, the improvement wherein the radiation diffusing and blocking layer is (a) interposed between the reagent layer and the support layer; (b) impermeable to the ligand, reagents of the reagent layer, and products of their interreaction; and (c) inert to the ligand, reagents of the reagent layer, and products of their interreaction.

Abstract: A multilayer analytical element for determining an assay of a component in whole blood sample is disclosed, which comprises at least two water-permeable layers, wherein one layer is a sample spreading layer and the other layer is a reagent layer, wherein one layer or more of said water-permeable layers contain a composition which interacts with said component in whole blood sample, wherein the composition forms a dye capable of being detected by a spectrophotometry at a wavelength of 600 n.m. or longer, when the composition interacts with said component in whole blood sample.