Abstract: The present invention relates to an immunoassay device featuring a semi-quantitative, multi-level method for determining the presence and an amount of an analyte. The immunoassay involves a device comprising a layer with a porous medium deposited thereon. The device has several binding zones in which each zone comprises a defined amount of a binding reagent to bind and immobilize the analyte. The present invention also features an inscribed capillary channel having fluid barriers that allow control of a rate of migration of fluid along the porous medium. The device typically provides at least some of the binding zones within the capillary channels such that a solvent quickly traverses through the capillary channels and provides a semi-quantitative result. Preferably, any binding of an analyte is accompanied by a visual change in the binding zone such that one can easily detect visually an amount of analyte present in the sample.

Abstract: An immunoassay procedure for detection of analytes in urine wherein an immunological reaction is conducted in an aqueous phase containing the urine and a filterable immunocomposite containing an inherently colored gold sol particle is formed if the assay is positive. The colored, gold sol particle containing immunocomposite is collected for direct visual observation on a filter element.

Abstract: An assay procedure for predicting the onset of the ovulation in a human subject. Urine samples are obtained on consecutive days and assayed for total gonadotropal alpha peptide chain content. The alpha chain content surges to indicate ovulation and the onset of the fertile period.

Abstract: A simultaneous dual analyte assay for determining the fertile period of the human menstrual cycle. The assay utilizes a capture reaction component consisting of P-3-G immobilized on a microporous membrane, a blocking reaction component consisting of anti E.sub.1 -3-G antibody, a labelled reaction component consisting of gold particle labelled anti E.sub.1 -3-G antibody, and an ambifunctional reaction component consisting of a hybrid immunoreactive substance having an anti P-3-G antibody binding site and a plurality of E.sub.1 -3-G determinant binding sites. An aqueous sample containing P-3-G and E.sub.1 -3-G is contacted with the components and the assay is calibrated to provide a positive assay result only when the concentration of P-3-G in the sample is less than a predetermined concentration and the concentration of E.sub.

Abstract: An immunoassay procedure for detection of analytes in urine wherein an immunological reaction is conducted in an aqueous phase containing the urine and a filterable immunocomposite containing an inherently colored gold sol particle is formed if the assay is positive. The colored, gold sol particle containing immunocomposite is collected for direct visual observation on a filter element.

Abstract: An immunoassay method comprising applying an aqueous solution containing the analyte antigen to one end of a multi-zoned test strip device such that the solution moves along the strip by capillary action. The zones are arranged so that the solution (a) first contacts and reconstitutes dry, diffusible labelled component comprising colloidal gold conjugated to an antibody specific for said analyte antigen and then (b) contacts and reconstitutes dry, diffusible biotinylated second antibody specific for said analyte antigen such that a diffusible, dispersed sandwich reaction product forms. The reaction product diffuses along the strip with the solution and into a zone containing capture component consisting of a latex and avidin complex which avidin collects the reaction product by means of reaction with its biotin moiety. Thus, gold particles are collected and concentrated in the detection zone for visual determination.

Abstract: A lyophilized mixture of reactants for an immunoassay includes antibody-gold sol particle conjugates, antibody latex particle conjugates, polyethylene glycol, a polyethylene glycol p-isooctylphenyl ether detergent and a sugar such as dextrin or trehalose. The polyethylene glycol is present to enhance binding of the immunoreactants and the polyethylene glycol p-isooctylphenyl ether detergent is present to prevent non-specific interactions. The sugar prevents agglomeration of the polyethylene glycol and polyethylene glycol p-isooctylphenyl ether in the lyophilized mixture at room temperature and facilitates retention of a homogenous distribution of the ingredients of the mixture to thereby enhance shelf life and redistribution of the mixture in an aqueous test system.

Abstract: Antibody coated gold sol particles and antibody coated solid phase particles dispersed in an aqueous system react immunologically as a function of the presence of an analyte in a sample to be analyzed to produce a collectible, solid phase, gold-containing composite. The composite is collected on a filter or at the bottom of a test tube by centrifugation or gravitation and the analyte in the sample is determined or detected by direct visual examination of the collected solid phase composite which has a pink or red or purplish coloration as a result of the gold contained thereby. The materials required for conducting the assay comprise coated gold particles, coated solid phase particles and a collector element such as a filter. The collected, solid phase, metal-containing composite, which may be directly visually examined to determine or detect the gold therein and thus the analyte in the sample, is stable and remains available for confirmation of test results at a later time.

Abstract: An immunoassay method utilizes antigen tagged, enzyme encapsulating liposomes which are immunospecifically ruptured in the presence of cognate antibody and active complement. A homogeneous phase reaction occurs with the antibody and complement acting to release the enzyme if an immunospecific antigen-antibody complex is formed at the surface of the liposome. The positions of the antigen and antibody can be reversed.

Abstract: An antigen or antibody and an immunochemically neutral protein are immobilized in two stages on a microporous membrane coated with a protein such as zein or collagen. Immobilized antigen to Toxoplasma gondii is used in an immunoassay to detect the presence of antibody to Toxoplasma gondii in serum. Antibody that becomes bound to the immobilized antigen is detected with an antibody- enzyme conjugate. Immobilizing the immunochemically netural protein on the membrane in a second stage immobilization step minimizes nonspecific binding during the immunoassay.

Abstract: An immunoassay method utilizes antigen tagged, enzyme encapsulating liposomes which are immunospecifically ruptured in the presence of cognate antibody and active complement. A homogeneous phase reaction occurs with the antibody and complement acting to release the enzyme if an immunospecific antigen-antibody complex is formed at the surface of the liposome. The positions of the antigen and antibody can be reversed.

Abstract: A test device for assaying liquid samples for the presence of a predetermined reagent is described. The device comprises telescoping top and bottom members defining a liquid reservoir therebetween, resilient means for biasing the members in the open position, one or more test wells in the top member with bottom openings covered with microporous membranes, a co-reactant immobilized on the membrane surfaces, and sorbent means between the members spaced from the membrane(s) in the open position but in contact therewith in the closed position. Liquids are passed through the membrane(s) into the sorbent means by depressing the members to the closed position.

Abstract: The presence of antigens is detected with a device having an antibody immunochemically reactive with the antigen bound to a first microporous membrane coated with an inert proteinaceous material and an antibody immunochemically non-reactive with the antigen bound to a second microporous membrane coated with an inert proteinaceous material. The device is particularly useful in an immunoassay for an antigen of Entamoeba histolytica in unfractionated feces or colon aspirate.