Abstract: A method and apparatus for detecting proper strip insertion into an optical reflectance meter. An electrical or electromagnetic device within the optical reflectance meter launches a signal when a test strip is inserted therein. The test strip which is designed for use in such a meter contains a material which enhances the coupling of the signal to a receiver within the meter. The meter then receives the signal and will not produce reading until a signal of a proper level is received. Use of the meter and special test strip of the present invention comprises a more cost effective system for detection of proper test strip insertion which is not dependent upon clean optics as in prior art devices. The present invention therefore ensures reliable protection of strip insertion with the ability to distinguish not only whether the test strip has been inserted incorrectly by the user, but also whether the test strip was designed for use with the meter into which it has been inserted.

Abstract: Disclosed is a testing device and methods for the identification of an analyte of interest in a sample. In a preferred embodiment, the testing device includes a front panel having at least one sample application aperture; a rear panel having at least one solvent application aperture; a sample collection matrix disposed between the rear panel and the front panel, the sample collection matrix being in communication with the sample and solvent application apertures of the front and rear panels; and an insertable test strip containing a reagent enabling detection of the analyte of interest.

Abstract: A strip for testing for the presence of an analyte generally comprises a support member which contains a spreading layer and a reagent layer, and a capillary tube in communication with the support layer and spreading layer for transporting a sample of body fluid thereto. A method of testing a fluid for the presence or concentration of an analyte is also provided which generally includes providing a test strip with a support member, a spreading layer, and a reagent layer on the spreading layer. A capillary tube is provided on the support member whereby a fluid containing an analyte to be tested is introduced into the tube and flows through the tube to the spreading layer and contacts the reagent layer.

Abstract: A culture material is formed containing a water-soluble polymer layer and a porous matrix layer arranged such that when water is applied to the surface of the matrix layer the water diffuses through the matrix layer to dissolve the water-soluble polymer layer which then gradually penetrates into the matrix layer to form a single layer for use as a culture medium on which a microorganism can be grown to form colonies. The water-soluble polymer layer or water added to the matrix layer can contain nutrients for the microorganism, and the microorganism can be added with the water. The culture material has a water content of not more than 50%, and is sufficiently insoluble in water such that it substantially holds its original shape for at least 30 minutes when in contact with water having a temperature of not more than 50° C.

Abstract: Lateral flow device and method are provided for performing semi-quantitative visual or instrument-based detection in a test sample of a large molecule analyte that contains two binding domains, &agr; and &bgr;. The device contains two reagents, a contrast reagent and an indicator reagent, and an analyte test zone (ATZ) that contains a fixed number of immobilized &agr;-domain-specific binding sites. The contrast and indicator reagents each contain signal generators such that the two reagents contrast each other in different regions of a visual, spectrophotometric, calorimetric or fluorometric spectrum. The contrast reagent is prebound to an &agr;-region-fragment of the analyte of interest and, therefore, does not react with the analyte of interest in the test sample. The indicator reagent is attached to a binding ligand specific for the &bgr;-domain of the analyte of interest.

Abstract: A test method and device are described for quantitatively determining the presence and concentration of monopersulfate ion in aqueous solution. Contacting the aqueous solution containing monopersulfate ion with a test strip in accordance with the invention produces a color change in proportion to the concentration of the ion. The invention has particular utility in maintaining the proper level of sanitizers in swimming pool water.

Abstract: A test device for detecting or determining an analyte in a test solution includes an absorbent material having separate contact, competitive binding, and measurement portions. The contact portion is positioned for contact with and uptake of the test solution. The competitive binding portion has a binding material for the analyte non-diffusively bound thereto. The measurement portion has a receptor for the analyte and marker-encapsulating liposomes non-diffusively bound thereto. In a method for using the test device, a solution containing the analyte and the analyte-liposome conjugate is allowed to traverse the absorbent material from the contact portion through the competitive binding portion and on through the measurement portion of the absorbent material. The amount of marker in the measurement portion of the absorbent material, following traversal by the test solution, is then determined as a measure of the analyte in the sample.

Abstract: A method of determining the concentration of IgG antibodies in the biological fluids of mammals. The assay may be performed in a lateral flow cassette or dipstick format where dehydrated immobilized reagents are spaced along a membrane. A sample of a mammalian biological fluid is exposed first to an IgG complexing agent to yield a conjugate. The conjugate then moves along the membrane and is exposed to a standard mammalian IgG applied to the membrane at a test position. Binding of the IgG is indicated by a color change at the test position on the membrane. A control reagent of dehydrated anti-IgG complexing agent may be applied to the membrane at the control position spaced downstream from the test position. Interaction of the IgG complexing agent with the anti-IgG complexing agent forms a visible line at the control position on the membrane.

Abstract: The use of calcium salts, magnesium salts or combination thereof in immunochemical methods for the determination of an analyte in a sample. These salts increase the specificity of such determinations, in particular, the background signal being reduced by addition of these salts in solid phase immunochemical methods.

Abstract: Disclosed is a testing device and methods for the identification of an analyte of interest in a sample. In a preferred embodiment, the testing device includes a front panel having at least one sample application aperture; a rear panel having at least one solvent application aperture; a sample collection matrix disposed between the rear panel and the front panel, the sample collection matrix being in communication with the sample and solvent application apertures of the front and rear panels; and at least one insertable test strip containing a reagent enabling detection of the analyte of interest.

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: A device for the separation of the liquid portion of blood from the cellular components of blood comprises: (1) a pad of porous material permeable to the liquid portion of blood but capable of trapping the cellular components of blood; (2) a substrate supporting the pad; and (3) means, attached to the pad, for facilitating the flow of the liquid portion of the blood: (i) through interstices around the trapped cellular components of the blood and (ii) from the pad of porous material. The separation of the liquid portion of blood from the cellular components of the blood occurs by flow through the pad of porous material without significant hemolysis. The device can be incorporated into a device for the performance of specific binding assays such as immunoassays. The pad of porous material can contain an agglutinating agent such as a lectin or an anti-blood cell antibody, or a carbohydrate such as mannitol.

Abstract: The invention relates in part to the use of independent assay controls (IACs) for the optical communication between an assay device and an instrument in monitoring and performing assays, preferably immunoassays.

Abstract: A diagnostic test strip for determining the presence of a specified analyte in a fluid sample is described. The test strip has a test membrane sandwiched between two layers of a plastic sheath. The upper layer of the sheath has a sample well into which a liquid sample is placed. The test membrane has a sample receiving zone typically containing a buffer and a fatty acid sarcosinate. Adjacent to the sample receiving zone is a reagent zone containing reagent chemicals including gold colloid particles coated with antibodies to the specified analyte. In fluid connection with the reagent zone is a test zone containing immobilized molecules of the specified analyte. Preferably, in fluid connection with the test zone is a control zone containing an indicator that changes color when wetted by the sample and a liquid sink zone to absorb excess liquid in the sample.

Abstract: This invention relates to the measurement of analytes in dried blood samples. It has been discovered by measuring the hemoglobin in the dissolved dried blood sample, an estimate of blood volume may be made and used to make a correction for blood volume. Thus, analytes such as cholesterol, PSA, and other blood analytes can be more accurately determined. The invention further describes a blood collection device and disk material on which blood is dried to provide superior results.

Abstract: An analytical test device useful for example in pregnancy testing, comprises a hollow casing (500) constructed of moisture-impervious solid material, such as plastics materials, containing a dry porous carrier (510) which communicates indirectly with the exterior of the casing via a bibulous sample receiving member (506) which protrudes from the casing such that a liquid test sample can be applied to the receiving member and permeate therefrom to the porous carrier, the carrier containing in a first zone a labelled specific binding reagent is freely mobile within the porous carrier when in the moist state, and in a second zone spatially distinct from the first zone unlabelled specific binding reagent for the same analyte which unlabelled reagent is permanently immobilised on the carrier material and is therefore not mobile in the moist state, the two zones being arranged such that liquid sample applied to the porous carrier can permeate via the first zone into the second zone, and the device incorporating mea

Abstract: A vessel for conducting blood cell agglutination assays is disclosed. A barrier retains reactants in an upper chamber during incubation, then, in response to a force, permits reagents to enter a lower chamber containing a matrix for separating agglutination.

Abstract: Disclosed is a method for determining the concentration of an analyte in a fluid test medium by use of an immunochromatographic test strip through which the test fluid can flow by capillarity. The test strip has at least two capture bands and optionally one or more collection bands which capture labeled anti-analyte antibody to provide a detectable signal. The signals from the label is quantitatively detected in each of the bands to provide a pattern of signals which is unique to the concentration of analyte in the test fluid. The pattern of signals are mathematically combined to create a monotonous dose-response curve to thereby factor out the high analyte hook effect which can be present in this type of assay.

Abstract: For blood or other physiological fluid sample collection kits that use filter paper to collect the sample, the performance of the kit and associated analytical method can be improved by using a material having properties which are superior to those of standard filter paper or modified filter paper routinely used in standard biological assays. Certain materials currently available for uses other than blood collection, storage, or transport have properties that are advantageous as employed in assays of biological fluids, including the use of specific cellulose blotting materials for collecting blood samples for hemoglobin or hemoglobin A1c monitoring.

Abstract: A dry phase reagent test strip for measuring the concentration of an analyte in a biological fluid includes a colored indicator whose hue indicates a calibration of the strip. Preferably, the test strip measures the concentration of glucose in whole blood.

Abstract: An assay device for the performance of immunochromatographic assays and other assays has two principal parts, a first opposable component and a second opposable component. The first opposable component can contain a sample preparation means and a second opposable component can contain a suitable chromatographic medium for detection of an analyte. Alternative embodiments of the invention can also exist. For example, the first opposable component can have a sample preparation means and a chromatographic medium that is not in communication with the sample preparation means and the second opposable component can contain a communicating means that, when the two components are brought into opposition, establishes a communication between the sample preparation means and the chromatographic medium. Assay devices according to the present invention can be used for both unidirectional and bidirectional assays.

Abstract: The invention provides a method for measuring the amount of analyte in a sample of biological fluid using a simple low sample volume reagent test strip with a built in metering system. The test strip may include a microtitration zone to prevent oversampling and an integrated capillary to prevent problems associated with short sampling and act as means of absorbing the fluid sample. The test strip comprises a wicking layer and a reaction matrix embossed layer in the form of a pillow assembled into a microtitration pocket formed in the strip. The test strip is used in single use applications such as the determination of the concentration of glucose in blood.

Abstract: The invention concerns an analytical test element containing an absorbent material with a sample application and detection zone and a blister filled with liquid on a support, wherein the support has a notch within the support surface such that a spike forms there when the support is bent with which the blister can be opened so that liquid escapes and comes into contact with the absorbent material as well as a process for the production of such an analytical test element and a method for determining an analyte by means of such an analytical test element.

Abstract: In a method of determining heparin content, a known amount of thrombin (FIIa) or activated coagulation factor X (FXa) is added to a mixture which comprises a known concentration of chromogenic substrate (S), a known concentration of antithrombin (AT) and a sample having an unknown heparin concentration. The amount of FIIa or FXa is chosen such that at most 20%, of the S present is reacted during the period which the AT needs to deactivate all the FIIa or FXa present. The final concentration of the reacted chromogenic substrate p-nitroanilide ([pNA].sub.final) is determined after completion of the reactions, and the [pNA].sub.final is used to determine the rate constant (k.sub.dec) of the reaction of FIIa or FXa with AT using the relationship: ##EQU1## The heparin concentration in the sample can then be determined using the value of k.sub.dec from a predetermined calibration curve of k.sub.dec against heparin concentration.

Abstract: A method of determining the concentration of an analyte in a sample, said method comprising bringing said analyte in contact with an indicator zone comprising a concentration gradient of a mobile binding member; and bringing said mobile binding member gradient into operable contact with a test zone comprising a fixed binding member, wherein a detectable signal that indicates the concentration of said analyte is produced.

Abstract: Novel magnetic assay methods and systems, as well as systems for conducting spectrophotometric analysis therewith. According to a preferred embodiment, the magnetic assay methods and systems incorporate a chromatographic medium, such as an assay test strip, that is designed to be contacted with a test solution having activated magnetic particles. A magnetic field, generated by a magnet or electromagnet, is additionally provided that if selectively applied to a chromatographic medium which causes the charged particles to become substantially bound at a site all in the chromatographic medium specified by the position of the magnets, to thus form a captured line or zone. To the degree of magnetic force applied to the medium may be selectively adjusted to vary the width or surface area of the capture line or zone. Additionally, in a preferred embodiment, capture lines may be formed while test strips are in motion along a stationary magnetized rail.

Abstract: A reagent useful in immunoassays, comprising a direct particulate level co-sensitized with a specific binding agent having specificity for an analyte or analyte analog and with a non-specific protein which can participate in a control reaction with another specific binding agent which does not bind to the first specific binding agent nor participate in the formation of a complex by means of which detection of the analyte or analyte analog is accomplished. Preferably the first specific binding agent is an antibody raised in a first species and the non-specific protein is an immunoglobulin from another species. Optionally, the reagent additionally comprises a second population of the direct particulate label sensitized solely with the non-specific protein.

Abstract: A process of manufacturing test strips of the type comprising a length of porous carrier material capable of acting as a liquid flow path for a sample liquid and having at least zone downstream from a first end of the strip which zone contains an immobilized specific binding agent to act as a capture means during an assay to reveal the presence of an analyte in applied sample liquid, and in which process the specific binding agent is deposited onto a sheet of the porous carrier material which is then blocked and subdivided into a plurality of individual identical test strips, wherein blocking of the porous carrier material is achieved by applying a solution of blocking agent to the sheet upstream from the zone in an amount sufficient to ensure that the solution permeates downstream to beyond the zone.

Abstract: A method of determining the concentration of a sample antigen in the presence of an interferant by(1) running two immunoassays on the sample: one assay where the interferant influences the binding of both the sample antigen and a labeled antigen and a second assay where the interferant influences the binding of the sample antigen but not the labeled antigen;(2) obtaining a plot of the possible sample antigen concentrations versus the possible interferant concentrations corresponding to the readout for the sample for each of the two immunoassays; and(3) determining the sample antigen concentration and the interferant concentration which correspond to the point that appears in both the immunoassays plots.

Abstract: A method and device are provided for the semi-quantitative and quantitative determination of an analyte in a sample. A non-competitive trap which can bind unreacted labelled receptor to analyte but has virtually no binding capabilities to receptor in the presence of analyte is used. Labelled receptor:analyte complex is trapped in a second trap. The relative amounts of unbound receptor in the non-competitive trap versus the amount of receptor:analyte complex in the second trap is a measure of the amount of analyte in the sample.

Abstract: The present specification describes a sterility indicator device which comprises a container means and a cover means. The container means comprises a plurality of discrete zones, wherein each zone contains biologically active substrate useful in determining the effectiveness of a sterilization process. Each zone is in effect an individual sterility indicator. The device results in increased reliability and accuracy due to the increased number of discrete zones. The number of discrete zones may be of sufficient size so as to provide statistically significant predictive values at the ninety-five percent or better confidence interval for lower numbers of surviving spores.

Abstract: An assay device for detection or determination of an analyte in a sample uses opposable components and is suitable for assay of human chorionic gonadotropin and other protein or glycoprotein hormones.

Abstract: A device for the separation of the liquid portion of blood from the cellular components of blood comprises: (1) a pad of porous material permeable to the liquid portion of blood but capable of trapping the cellular components of blood; (2) a substrate supporting the pad; and (3) means, attached to the pad, for facilitating the flow of the liquid portion of the blood: (i) through interstices around the trapped cellular components of the blood and (ii) from the pad of porous material. The separation of the liquid portion of blood from the cellular components of the blood occurs by flow through the pad of porous material without significant hemolysis. The device can be incorporated into a device for the performance of specific binding assays such as immunoassays. The pad of porous material can contain an agglutinating agent such as a lectin or an anti-blood cell antibody, or a carbohydrate such as mannitol.

Abstract: A method is disclosed for determining the presence or amount of analyte in a fecal sample. The method comprises the steps of (A) contacting the fecal sample with an extraction reagent comprised of at least one detergent and at least one buffer to form a mixture, (B) applying the mixture to an absorbent filter that is in proximity to or in contact with an immunoassay such that analyte present in the sample is transferred to the immunoassay, and (C) detecting the presence of analyte by said immunoassay. In a preferred embodiment, the immunoassay comprises a porous strip containing immunoreagents for detecting analyte.

Abstract: A test device which includes a housing having an immunochromatographic test strip therein is disclosed. The test strip is color-coded so that the presence or absence of a substance or substances in a fluid sample may be detected and identified. The strip also indicates the locations of the immunoreactions that will take place on the test strip by means of colored lines. Sample is applied onto the strip through a window and is spontaneously wicked up the test strip mobilizing a dye-microspherical antibody located in a first zone on the strip. The dye particles then move along the membrane strip by capillary action to a second zone. In the absence of specific antigen in the sample, the dye-microsphere particles attach to the antigen in the second and third zones through immunocomplexation, forming definite, visible lines. This is a negative test.

Abstract: The invention is an improved single-step test device for detecting the presence of a pre-selected analyte in a urine stream. The device includes a hollow rectangular outer casing and an assay material disposed within co-joined upper and lower sections of the casing. The outer casing includes a urine inlet port; a viewing window in the upper section; at least the upper section consisting of transparent material; and may also include at least one drainage vent spaced about the urine inlet port. The assay material is a sorptive material including: a urine sample application region adjacent to, and in fluid communication with the urine inlet port; a capture region adjacent to the viewing window; and a fluid flow path for transporting a liquid sample between the urine sample application region and the analyte capture region. The flow of urine in the fluid path is observable through the transparent upper section for confirming a test is operative.

Abstract: This invention relates to the measurement of analytes in dried blood samples. It has been discovered by measuring the hemoglobin in the dissolved dried blood sample, an estimate of blood volume may be made and used to make a correction for blood volume. Thus, analytes such as cholesterol, PSA, and other blood analytes can be more accurately determined. The invention further describes a blood collection device and disk material on which blood is dried to provide superior results.

Abstract: An improved multi-layered diagnostic sanitary test strip for receiving a heterogenous fluid, such as whole blood, to test for presence and/or amount of a suspected analyte in the fluid by facilitating a color change in the strip corresponding to the amount of the analyte in the fluid, wherein the test strip includes fluid volume control dams to prevent spillage of the fluid from the strip and a chemical reagent solution that facilitates end-point testing. The improved test strip comprises (a) an upper support strip having a fluid receiving port and (b) a lower support strip having a color change viewing port and securely sandwiched therebetween (c) a spreading mesh screen for uniformly distributing the fluid, (d) a chemically treated separating layer for removing an undesirable element, e.g.

Abstract: An immunochemical assay device comprising a base member, an array disposed on the base member, and at least one assay indicia zone. The array comprises (i) a reservoir pad to receive sample liquid, (ii) a wicking membrane, and (iii) at least one filter zone interposed between the wicking membrane and the reservoir pad. The filter zone being operable to permit passage of any specific immunocomplex to the wicking membrane while impeding passage of larger components.

Abstract: An article for detecting thermostable nuclease positive, potentially enterotoxigenic, staphylococci, containing unhydrolyzed nucleotides, toluidine blue O, and a binder, wherein the article is adapted for placement against a sample suspected of containing enterotoxigenic staphylococci. A method of detecting thermostable nuclease positive staphylococci in a sample utilizing the article, and a kit for the detection of thermostable nuclease positive staphylococci containing the article, are also described.

Abstract: An assaying device and a method of manufacturing same are provided. The assaying device includes a unitary, absorbent membrane having multiple reagent stripes incorporated therein. The reagent stripes display an observable reaction if a sample component is present in a fluid sample being tested. The reagent stripes are deposited simultaneously on a continuous membrane ribbon and individual membranes are die cut therefrom. Each individual membrane includes commonly connected channels having die cut slots therebetween. The channels are preferably disposed perpendicularly with respect to the reagent stripes and provide means for causing contact between the fluid and reagent stripes. The present invention preferably includes a cassette for containing the membrane and for facilitating analysis of test results.

Abstract: A device for the separation of the liquid portion of blood from the cellular components of blood comprises: (1) a pad of porous material permeable to the liquid portion of blood but capable of trapping the cellular components of blood; (2) a substrate supporting the pad; and (3) means, attached to the pad, for facilitating the flow of the liquid portion of the blood: (i) through interstices around the trapped cellular components of the blood and (ii) from the pad of porous material. The separation of the liquid portion of blood from the cellular components of the blood occurs by flow through the pad of porous material without significant hemolysis. The device can be incorporated into a device for the performance of specific binding assays such as immunoassays. The pad of porous material can contain an agglutinating agent such as a lectin or an anti-blood cell antibody, or a carbohydrate such as mannitol.

Abstract: A method of assaying a preselected volume of sample on an chromatographic strip includes providing a sample receiving reservoir. This reservoir can receive a preselected volume of sample or a preselected volume of sample and reagent. The sample receiving reservoir has an overflow outlet. A moat is communicated to the overflow outlet of the sample receiving reservoir for receiving the sample or sample and reagent when the sample receiving reservoir is full. The mixed sample or sample and reagent fill the sample receiving reservoir, and discharge the excess sample through the overflow outlet to the moat. The sample receiving reservoir having the preselected volume of sample or sample and reagent is discharged on the chromatographic strip for assay. Provision is made for adding a density adding solute which is neutral to the chromatographic strip, the density adding solute occupying the sample receiving reservoir.

Abstract: An apparatus in the form of a test strip is useful for determining the presence of one or more components in a fluid sample. The test strip can be used by itself or in conjunction with an associated housing assembly. The test strip provides a rapid volume, timing and temperature independent visually readable strip for the semi-quantitative detection of a component, such as an analyte.

Abstract: A chromatographic assay device for use with immunoassays allows rapid and convenient assays of analytes of biological interest, and permits extractions to be carried out in situ, avoiding the use of separate extraction vessels. The device has a wide dynamic range and avoids interference from particulates or colored components. In one form, the device comprises: (1) a first opposable component comprising a sample preparation means adapted to receive a sample to be assayed; and (2) a second opposable component comprising a chromatographic medium. The first and second opposable components can be brought into opposition so as to cause the sample preparation means to apply the sample to be tested to the chromatographic medium. Preferably, the analyte is detected with a visually detectable label. Other variations of the device vary the arrangement of components to provide optimal chromatography for a variety of analytes, as well as to permit bi-directional chromatography.

Abstract: Disclosed is a test cell and a method for detection of a preselected ligand in a liquid sample such as a body fluid. The test cell includes an elongate outer casing which houses an interior permeable material capable of transporting an aqueous solution and defining a sample inlet, a test volume, and a reservoir volume. The reservoir volume is disposed in a section of the test cell spaced apart from the inlet and is filled with sorbent material. The reservoir acts to receive liquid transported along a flow path defined by the permeable material and extending from the inlet and through the test volume. In the test volume is a test site which includes a first protein having a binding site specific to a first epitope of the ligand immobilized in fluid communication with the flow path. The test site can be observed through a window of the casing.

Abstract: A method for evaluating the solubility capacity of free unbound estrogens in body fluids of animals is described.

Abstract: A test strip for a rapid immunoassay containing specific immunochemical reagent zones (7, 8, 9) is described. The test strip (10) has a backing sheet (1) and attached thereto a receiving end pad (3) and at a distance therefrom a finishing end pad (5). A test membrane (2) is provided between said pads (3, 5). Said membrane (2) is positioned in parallel relationship to said backing (1) at a distance therefrom so that said backing (1) and said membrane (2) limit between themselves an air gap (4) which is open at its edges. Said gap (4) functions as a sheltered reaction chamber for the immunolgical reaction taking place as a liquid is made to flow through said membrane (2). The test strip is simple to manufacture by lamination and easy to use and it is suitable for both diagnostic and environmental immunoassays.

Abstract: A multi-test panel with several test strips containing a separate and different immunochromatographic system, each strip being housed in a separate structure so that the structures may be joined together and interchanged, depending upon what substances within a fluid sample are being detected.

Abstract: Devices and methods for utilizing dry chemistry dye indicator systems for body fluid analysis such as glucose level in whole blood are provided by incorporating a porous membrane with a skin side which enables separation of whole blood and visually reading the indicator without removing the red blood cell portion of the blood from the membrane. The devices also enable visual reading of the indicator by use of a cellulose fiber glass composite matrix which provides separation of whole blood in a lateral flow of the blood through the matrix from the input area to a test area of the matrix. Another aspect of the device provides a determination of hematocrit level in whole blood by measuring flow rate through a restricted passageway in the device.