Abstract: The invention relates to a method for determining an analyte by means of binding reactions, which method comprises: i) applying the sample to an application zone for sample (ASZ) on a flow matrix in which transport of components present in the sample can take place (transport flow), the flow matrix further exhibiting: a) optionally an application zone (AR*Z) for a binding reactant (Reactant*=R*) which is analytically detectable; b) a detection zone (DZ), which is located downstream of ASZ and exhibits an additional binding reactant (Capturer) firmly anchored to the matrix, and in which a complex (signal complex) containing the Capturer and the analyte and/or Reactant* is formed during the reaction, and ii) detecting the signal complex in the detection zone, the measured signal being used for determining the analyte.

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: The present invention involves a method and an immuno-analytical device for the rapid and simultaneous detection of multiple micro-organisms in the biological fluids from milk-producing animals suffering from mastitis. This method is based on a lateral flow immuno-assay technique performed to detect antigens specific for multiple infectious agents which are known to cause and/or be encountered in cases of mastitis. Mastitis is an inflammatory condition affecting the udders of milk-producing animals as a result of microbial infections.

Abstract: The invention relates to an immunoassay apparatus, comprising a dry, porous substrate having at least two sections (1, 2), communicating with one another in the moist state by capillary action, wherein the first section (1) has a marked detection reagent for the substance to be detected and the second section (2) has an immobilized binder reagent for the substance to be detected, and wherein the reaction product comprising the substance to be detected and the marked detection reagent migrates by capillary action from the first section into the second section in the moist state, and is characterized in that the marked detection reagent is a dye-carrying reagent for nicotine or cotinine.

Abstract: One-step enzyme immunoassays in which enzyme-antibody conjugate or label and enzyme substrate are separated until separation of bound and free enzyme conjugate or label is complete. This separation is accomplished by using variable flow paths, immobilization of substrate at the test line, placement of substrate in a sac or association with a particle label, enzyme product chemical capture, delay zone dissolution and protected enzyme substrates.

Abstract: A test device (20) for detecting semen includes a strip (22) having an introduction station (24), a test station (26), and a control station (28) disposed in spaced apart relationship. The introduction station (24) has labeled p30 antibodies, the test station (26) has immobilized p30 antibodies, and the control station has immobilized polyclonal antibodies. A test sample (500) is deposited in the introduction station (24). If semen is present in the test sample (500), a colored line will appear at the test station (26) and at the control station (28). If no semen is present in the test sample (500), a colored line will only appear at the control station (28).

Abstract: One embodiment of the present invention improves the visual use of urine test strips and reagent pads by providing a single color from a reference color spectrum directly on the colorimetric strip and adjacent to the reagent area to allow easy comparison. After application of a fluid to be tested to a reagent area on the colorimetric strip, a technician is able to easily compare the color in the reagent area to the reference color area(s) to determine the presence or absence of, for example, glucose, in the fluid. Placing at least one reference color immediately next to the reagent area markedly improves technician's accuracy in comparing and analyzing the reagent area against the reference color(s). The present invention allows a technician to easily and quickly compare a reagent area color to more than one reference area to determine the actual numerical value of, for example, the pH in the tested fluid.

Abstract: A chromatography assay device and method for use with whole blood samples utilizing a red blood cell separating agent to aggregate red blood cells and permit plasma or serum to flow by capillary action and a neutralizing agent to neutralize any effects the red blood cell separating agent may have on the device and method.

Abstract: The present invention is directed to a single test system and method for determining the integrated glycemic condition of a subject by measuring the concentration of glucose and the level of protein-bound glucose in a subject's body fluid, such as whole blood. The glucose concentration is indicative of the subject's immediate glycemic condition, whereas the protein-bound glucose concentration is indicative of either intermediate or long-term glycemic condition. Optionally, other analytes indicative of glycemic condition, such as ketone bodies or fatty acid derivatives, can also be measured. The present invention also provides a method of diagnosing diabetes. The invention additionally provides a method for analyzing the concentration of fructosamine in less than or equal to five minutes without the use of a reaction accelerator.

Abstract: A reagent is suitable for measuring the concentration of an analyte in a hemoglobin-containing biological fluid, such as whole blood. The reagent comprises a flavin-dependent enzyme that has specificity for the analyte, a flavin cofactor if, and only if, a flavin is not bound to the enzyme, a tetrazolium dye precursor, an electron transfer agent, and a nitrite salt. The reagent causes dye formation that is a measure of the analyte concentration. The nitrite salt suppresses interfering dye formation caused non-enzymatically by the hemoglobin. Preferably, the reagent is used in a dry strip for measuring glucose in whole blood.

Abstract: A process challenge device tailored to mimic the resistance of a particular product-package combination to a particular biological inactivation, disinfection, or sterilization process. The device is used to challenge the process, thus providing a means to validate the efficacy of the process. In one embodiment, the process indicator includes a biological indicator organism stored on a carrier enclosed within a chamber formed by a barrier film material. The specific indicator organism and carrier substrate are chosen for their appropriateness for a given process. The materials comprising the barrier film material of the process challenge device are chosen for the materials' specific resistance to the given process. The process challenge device may also comprise a separate second chamber filled with an appropriate culture medium or enzyme substrate that is separated from the chamber containing the process indicator by a separation means, such as a valve, a clip, or a frangible separation.

Abstract: A method and apparatus for extracting, identifying, and manipulating proteins or peptides from a solution uses paramagnetic beads having a coating with an affinity for the target component. In one embodiment, paramagnetic beads coated with C18 are used to adsorb proteins and peptides. The beads can be used to purify, immobilize and assay antibodies. By cycling the beads, many times greater molar amount of binding partner may be separated from a solution. A magnetic probe is used to capture the beads and transfer the beads to selected processing stages.

Abstract: The present invention provides internally calibrated competitive assays for use on a solid support. Additionally, the invention provides a method of using such assays.

Abstract: A device for culturing microorganisms and its use are described. The claimed device comprises a substrate having a top side, a pedestal mounted on the top side of the substrate and comprising a non-absorbent culture surface, a flexible cover sheet attached to the substrate and comprising a bottom surface, the cover sheet being configured to cover the culture surface, and a culture medium deposited on one or more surfaces selected from: the culture surface, and the cover sheet bottom surface. An aqueous sample is spread and contained by the claimed device without additional equipment or manipulation by the end user.

Abstract: A device and method for filtering a biologically derived sample and for mixing the sample with a reagent, comprising a fluid container defining a reservoir compartment and including a container outlet, a filter and a fluid flow-through matrix disposed in a flow path between the reservoir compartment and the container outlet. Water-soluble, dried reagent is retained on the matrix. Means is provided for urging sample in an aqueous liquid in the reservoir compartment through the filter and matrix and out the container outlet. Pressure is applied to the sample in an aqueous liquid in the reservoir compartment to cause the sample to flow in liquid through the filter and matrix and out of the container for analysis.

Abstract: A method to facilitate recovery troponin I and/or troponin T from a sample comprising addition of troponin C to the sample or to a surface from which the troponin I and/or troponin T are recovered.

Abstract: A device for depositing cells on an analytical plate includes a reception chamber which is to be placed above the analytical plate and whose bottom is open, and a material for absorbing a fixative in a cell suspension in the reception chamber. The absorbent material has a hole therein whose interior wall forms an extension of the reception chamber that defines a gap between the reception chamber and the analytical plate through which the cell fixative is absorbed.

Abstract: An immunochromatographic assay employing superparamagnetic particles to lable the target analytes. An opaque cover prevents misinterpretive readings in field situations and provides a protective surface on the porous membrane. Additional features include separability of the test strip from any backing or housing which is configured to support the strip, and that quantitative measurements of the target analytes are easily and accurately made by means of an electromagnetic reader device.

Abstract: A chromatography immunoassay device is described which can be used more easily, is protected from moisture and/or oxygen more effectively and can be produced at a lower cost than known chromatography immunoassay devices. The chromatography immunoassay device of the present invention is one in which one or more chromatography strips are stuck on a substrate made of a plate, each of the chromatography strips is sealed by closely adhering a substrate portion surrounding each chromatography strip to a seal film located on the chromatography strip, and the seal film and/or substrate possesses a film containing a dehumidifying agent and/or a film containing an oxygen absorbing agent.

Abstract: A method is disclosed for obtaining and/or immunologically detecting an analyte contained in a gas phase by immunologically binding the analyte to a binding partner thereof contained in a gas- and liquid-permeable first carrier matrix. Said method is characterized in that a) the analyte-containing gas phase is brought into contact with the first carrier matrix (immune adsorber), b) the analyte is bound to the first binding partner which is contained in the first matrix and not bound to the matrix, and c) the complex of analyte and first binding partner and the free first binding partner are eluted from the first matrix, d) the eluted complex or the free first binding partner is determined as a measure for the amount of analyte present.

Abstract: A multilayer analytical element for determining a level of an analyte on a substrate and adapted for use with hydrogen peroxide and an affinity-enzymatic compound of formula A-C-B, wherein A is a detecting agent having affinity for the analyte, B is an enzymatic visualizing agent consisting of peroxidase and C is a binding agent linking the detecting and visualizing agents together. The multilayer analytical element of the invention comprises a solid support and a hydrophilic layer thereon, the hydrophilic layer being formed of gelatin, polyvinyl alcohol or a mixture thereof and containing a developing agent and a hydrophobic color-producing agent in a total amount of 5 to 30 weight %, the developing agent and the color-producing agent being present in a weight ratio of 1:0.3 to 1:3.0.

Abstract: A disposable, dry chemistry analytical system is disclosed which is broadly useful for the detection of a variety of analytes present in biological fluids such as whole blood, serum, plasma, urine and cerebral spinal fluid. The invention discloses the use of the reaction interface that forms between two liquids converging from opposite directions within a bibulous material. The discovery comprises a significant improvement over prior art disposable, analytical reagent systems in that the detectable reactant zone is distinct and separate from the unreacted reagents allowing for the use of reaction indicators exhibiting only minor changes as well as extremely high concentrations of reactants. In addition, staged, multiple reagents can be incorporated. Whole blood can be used as a sample without the need for separate cell separating materials.

Abstract: Diagnostic devices, systems and methods for detecting the presence of an analyte in a sample are provided. In one embodiment, the device comprises a substrate, a binder printed in a pattern onto a surface of the substrate, and a means for directing a sample towards the surface of the substrate that is printed with the binder. Systems of the present invention further include a light source that can be directed through the aforementioned means or another opening to the binder-printed surface to test for diffraction.

Abstract: The penicillin biosensor (10) has a pH-sensitive polymeric hydrogel (30) in a rigid enclosure (20). The hydrogel includes an immobilized enzyme such as penicillinase. The enzyme catalyzes a chemical reaction consuming penicillin and producing penicillic acid. The hydrogel changes its osmotic pressure in proportion to the concentration of the penicillic acid. By measuring the change in osmotic pressure with a pressure transducer (40), the biosensor (10) is able to accurately measure the concentration of penicillin. A battery (64) powered monitoring device, connected to the biosensor (10) through electrical wires, is operably programmed to display the penicillin concentration in a computer (62) as well as to activate LED or buzzer as an alert in case that the measured concentration of penicillin is over the threshold concentration.

Abstract: Devices, systems, methods and kits are provided for use in determining the concentration of chemical and biochemical components in aqueous fluids. The subject devices include test strips which define a longitudinal axis and include a distal edge configured for insertion into a measurement instrument and having an alignment notch formed in the distal edge for engagement with an alignment member of the measurement instrument. The alignment notch has opposing edges wherein at least a portion of the opposing edges is in substantially parallel relation to the longitudinal axis. In using the subject devices, the devices are inserted into a measurement instrument having an alignment pin. When operatively engaged with the alignment pin, the notch serves to maintain the device in a substantially motionless position. The invention is useful in a variety of applications, particularly in the determination of blood glucose concentrations.

Abstract: This invention provides methods of retentate chromatography for resolving analytes in a sample. The methods involve adsorbing the analytes to a substrate under a plurality of different selectivity conditions, and detecting the analytes retained on the substrate by desorption spectrometry. The methods are useful in biology and medicine, including clinical diagnostics and drug discovery.

Abstract: Devices, systems, methods and kits are provided for use in determining the concentration of chemical and biochemical components in aqueous fluids. The subject devices include test strips which define a longitudinal axis and include a distal edge configured for insertion into a measurement instrument and having an alignment notch formed in the distal edge for engagement with an alignment member of the measurement instrument. The alignment notch has opposing edges wherein at least a portion of the opposing edges is in substantially parallel relation to the longitudinal axis. In using the subject devices, the devices are inserted into a measurement instrument having an alignment pin. When operatively engaged with the alignment pin, the notch serves to maintain the device in a substantially motionless position. The invention is useful in a variety of applications, particularly in the determination of blood glucose concentrations.

Abstract: An apparatus for taking an intestinal sample of a human or animal patient comprises a holder part (1) and an expandable part (2) supported by the holder part and having one or more sampling areas (8) on the surface thereof. The expandable part (2) is in a non-expanded state rectally insertable into and retractable from the patient's intestine, and in an expanded state, inserted into the patient's intestine, the expandable part is capable of contacting the intestinal wall with at least one sampling area (8; 14). The apparatus further comprises protective livers (7a, 7b) for preventing said sampling area or areas (8) from contact with the intestinal wall and intestinal fluid at least when the expandable part (2) in the non-expanded state is being rectally inserted into the patient's intestine.

Abstract: The present invention relates to a sintered porous polymeric material useful as membrane in an analyte detection device, such as a lateral flow device, flow through device, or a dipstick device. The invention encompasses an analyte detection device that comprises such a sintered porous polymeric material and method of analyte detection using such a device. Specific sintered porous polymeric materials encompassed by the invention are surface activated and further coated with one or more layers of a variety of materials.

Abstract: An automated system for preparing a plurality of cytological specimens from a plurality of fluid samples in vials includes an apparatus for collecting a monolayer of cells from each sample and transferring the cells to a microscope slide for fixing, staining, and inspection. The system includes a first loading station for receiving the sample vials, a second loading station for receiving consumables such as filter membranes, a slide dispenser, and an unloading area for removing completed specimen slides. To maintain one-to-one correlation between the samples and specimens produced therefrom, the system includes a subsystem for identifying each sample and permanently marking each slide with corresponding indicia prior to transferring the specimen thereto.

Abstract: A sample carrier generally comprises a sample node and an identifier co-located with the sample node. A sample node may be operative to carry a discrete sample, while an identifier may be operative to provide information associated with the sample carried by the sample node. Embodiments of a sample carrier may comprise a plurality of sample nodes supported in a predetermined spatial relationship relative to a respective sample container such as a respective well of a multi-well plate. A system and method of transferring specimens to a sample carrier include contacting a sample node to the specimen and encoding information associated with the specimen on the identifier. Various alternatives are disclosed wherein the specimen is solid, gaseous, and liquid in form.

Abstract: A device for determining a substance contained in a body fluid is provided. An indicator member has a testing zone that changes the color based on the concentration level of the substance contained in a body fluid applied to the testing zone. The indicator member is rotatably mounted on a basic carrier. A set of differently colored color fields is provided on the basic carrier along the circumference of a circle having a radius from the center of said basic carrier. The indicator member rotates about the center of said basic carrier. The changed color of said testing zone of said indicator member is compared to said differently colored color fields on the basic carrier.

Abstract: A chromatographic assay or test device for detection and/or determination of an analyte in a test sample, comprises a base member, and a chromatographic medium located in or on said base member, the base member being provided with a receptacle to receive an applicator having the sample applied thereto, and the applicator being movable when located in said receptacle between a first position in which the applicator is out of fluid contact with the chromatographic medium, and a second position in which the applicator is in fluid contact with the chromatographic medium so as to apply a sample on the applicator to the chromatographic medium. In an alternative aspect, the test device comprises a base member, and a second member, at least one of the base member and the second member including a chromatographic medium, and the second member being slidably movable with respect to the base member from a first position to a second position.

Abstract: A disposable, dry chemistry analytical system is disclosed which is broadly useful for the detection of a variety of analytes present in biological fluids such as whole blood, serum, plasma, urine and cerebral spinal fluid. The invention discloses the use of the reaction interface that forms between two liquids converging from opposite directions within a bibulous material. The discovery comprises a significant improvement over prior art disposable, analytical reagent systems in that the detectable reactant zone is visually distinct and separate from the unreacted reagents allowing for the use of reaction indicators exhibiting only minor changes as well as extremely high concentrations of reactants. In addition, staged, multiple reagents can be incorporated. Whole blood can be used as a sample without the need for separate cell separating materials.

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 an indicator in a bibulous matrix contained inside a hollow fiber capillary tube adapted to wick the fluid sample into the tube to wet the matrix and indicator system. The devices also enable visual or meter reading of the indicator by positioning the hollow fiber capillary tube in a housing having an optical opening adapted for receiving light form a source and directing the light to the capillary tube and for directing the light reflected therefrom to a detector. An advantage for the individual user is the small fluid, e.g., blood sample required, which enables the user to avoid using finger tip sticks for samples. Another aspect of the device provides a determination of and correction for hematocrit level in whole blood in combination with indicator indication of analyte concentration.

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 immunoassay device which comprises a Chromatography strip having a substrate adhered to the under surface thereof and a protective laminate adhered to the top surface thereof, wherein a space is arranged on the top and/or under surface of at least a partial region of a coloring region of the chromatography strip.

Abstract: A competitive assay strip and method of rapid competitive assay incorporating an additional step, allowing optimization or at least substantial improvement of conditions for competition between analyte conjugates and analytes or alternatively, binding of analyte, which is tailored to each particular analyte.

Abstract: An improved rapid diagnostic device, assay and multifunctional buffer reagent are provided for the detection of a target analyte in a fluid test sample. The 2-step assay utilizes a dual component flow-through device comprising a test unit and a post-filter unit capable of receiving the fluid sample and multifunctional buffer, respectively. The test unit comprises a reaction zone containing immobilized capture reagent that can specifically bind to the target analyte, an absorbent zone supporting the reaction zone, and optionally, a blood separation zone in lateral fluid communication with the reaction zone. The post-filter unit comprises a label zone permeated with a dried indicator reagent which is capable of being placed in transient fluid communication with the reaction zone of the test unit during the assay procedure. The rapid diagnostic assay system reduces the number of assay reagents, method steps and time required for performance compared to other conventional assays.

Abstract: This invention discloses a method and composition for detecting the presence of class specific antibodies reactive with analytes such as bacteria, allergens, autoimmune antigens, viral proteins, and carbohydrates by lateral flow techniques. In one embodiment of the invention, a test sample obtained from bodily fluids reacts with a gold labeled antigen. The resulting complex travels across the membrane, and along the lateral flow strip. Red colored lines formed in specific locations along the test strip indicate the presence of class specific antibodies in the test specimen. In another embodiment of the invention, the lateral flow assay serves as an immunochromatographic screening test for the detection of allergen-specific IgE antibodies in human serum. Test sample reacts with gold labeled anti-IgE antibody. The resulting complex travels across the membrane where immobilized allergens capture the allergen specific IgE complex.

Abstract: A test strip adapted to receive a sample and detect an analyte therein is provided. The test strip comprises a sample addition zone to which a sample may be added; an absorbent zone proximal to the sample addition zone; one or more test zones distal to the sample addition zone, at least one of the test zones including a first analyte binding agent immobilized therein which is capable of binding to the analyte to be detected; and a terminal sample flow zone distal to the one or more test zones, the absorbent zone being positioned relative to the sample addition zone and having an absorption capacity relative to the other zones of the test strip such that a distal diffusion front of a sample added to the sample addition zone diffuses from the sample addition zone to a distal diffusion point within the terminal sample flow zone and then reverses direction and diffuses proximal relative to the one or more test zones.

Abstract: Envelopes and other containers intended for mail transportation possess a biological agent/toxin indicator operative upon the interior in detection of volatile bases including gaseous amines released from bacterial biological agents including Bacillus antracis, i.e. anthrax. The biological agent indicator has an acidic acid-base indicator compound that irreversibly changes color when neutralized by volatile bases. The compound is applied in liquid form to an appropriately porous substrate. A polymeric matrix is specifically suggested for this substrate. Irreversible indication of the presence of volatile bases including amines produced by live bacterial agents as toxins at temperate ambient conditions down to below freezing is provided. An indicator compound having a pH of 2-5 is recommended. Halogenated xanthene, sulphonated azo, and sulphonated hydroxy-functional triphenylmethane dyes are suggested.

Abstract: A biosensor (10) has a hydrogel (30) in a rigid and preferably biocompatible enclosure (20). The hydrogel (30) includes an immobilized analyte binding molecule (ABM) and an immobilized analyte. The immobilized analyte competitively binds with free analyte to the ABM, thus changing the number of crosslinks in the hydrogel (30), which changes hydrogel swelling tendency (and thus the osmotic pressure) in its confined space in proportion to the concentration of free analyte concentration. By measuring the change in hydrogel pressure with a pressure transducer (40), the biosensor (10) is able to accurately measure the concentration of the free analyte molecule without the problem of oxygen limitations and interference encountered by prior art biosensors. A battery (64) powered telemeter (60) operably engaged to the pressure transducer (40) sends a radio data signal to a receiver (66) containing an alarm system operably attached to a computer (62).

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

Abstract: Methods for quantitatively measuring the amount of an analyte of interest in a fluid sample are disclosed. The methods involve providing a membrane having an application point, a detection zone, and a contact region, where the contact region is between the application point and the detection zone, and has test particles and internal control particles imbedded within it; contacting the application point with the fluid sample; maintaining the membrane under conditions sufficient to allow fluid to transport analyte by capillary action to the contact region, where the analyte binds to the test particles; further maintaining the membrane under conditions sufficient to allow fluid to transport analyte-bound test particles and internal control particles to the detection zone, where they interact with a detection reagent; and detecting the amount of test particles and the amount of internal control particles in the detection zone.

Abstract: A method of determining the gender of a bird in ovo comprises detecting the presence or absence of an elevated level of a sex-related hormone in the extra-embryonic fluid of the bird egg, and then determining the gender of the bird within the egg from the presence of an elevated level of a sex-related hormone therein. Preferably, the sex-related hormone is an estrogen. Further preferred are methods in which the extra-embryonic fluid is allantoic fluid. The method is preferably carried out on chicken eggs prior to or during transfer of the eggs from incubator to hatcher.

Abstract: Apparatus and methods for modulating flow rates in microfluidic devices are provided. The methods involve modulating downstream pressure in the device to change the flow rate of materials in an upstream region of the device. Such methods include electrokinetic injection or withdrawal of materials through a side channel and the use of an absorbent material to induce wicking in the channel system. The apparatus provided includes a prefabricated wick in the device to provide for flow rate control. Additional methods for determining velocity of a particle and cell incubation time are also provided.

Abstract: The present invention concerns a method for the detection of nucleic acids on an analytical element which contains a sample application zone and a detection zone, the analytical element enabling liquid transport from the sample application zone to the detection zone, wherein a sample is applied to the sample application zone of the analytical element and the nucleic acids contained in the sample are denatured and can be detected qualitatively in the detection zone by hybridization with a detection probe and also quantitatively, preferably by means of marker groups. In addition new analytical elements and reagent kits for the detection of nucleic acids are provided.

Abstract: System, method, and test strip for solid phase, electrochemical, quantitative analysis of analytes contained in biological fluid samples. Preliminary to analysis, a test sample solution can be applied to a sample collection pad associated with the solid phase test environment of the test strip. The test sample solution and a test kit reagent are thereby initially contacted, under assay conditions, within this solid phase test environment, and caused to migrate along a fluid pathway therein. Irrespective of the assay format (competitive assay, sandwich assay, etc.), a test kit reagent (e.g. labeled substance) and the analyte of interest (e.g.

Abstract: A chromatographic test strip comprising a solid support having at least a first portion and a second portion with said portions being in the same plane so as to permit capillary flow communication with each other. The sample is added to the first portion. The first portion also may comprise a tracer portion having a tracer movably supported therein. The tracer consists of a visible particulate marker. In the second portion, a binder is immobilized. The test strip is useful in a variety of immunoassays.