Abstract: A multizone test device for the determination of analyte in a liquid test medium. The test device preferably comprises multilayers including a first layer comprising a solid, porous matrix incorporated with a reversibly immobilized first reagent and a second layer comprising a solid, porous matrix incorporated with a second reagent which interacts with the first reagent and analyte from the liquid test medium to provide a detectable signal. A reversible binding interaction between the first reagent and the matrix of the first layer prevents the first reagent from prematurely migrating into the second layer during manufacture of the device and prior to application of the liquid test medium to the test device. The reversible binding interaction is sufficiently disruptable by contact of the first layer with the liquid test medium to release and thereby render diffusible an analytically effective amount of the first reagent within the test device.

Abstract: This disclosure relates to a method and reagents for determining ligands in biological fluids such as serum, plasma, spinal fluid, amnionic fluid and urine. In particular, this disclosure relates to a fluorescence polarization immunoassay procedure and to a novel class of tracer compounds employed as reagents in such procedures. The procedure disclosed combines the specificity of an immunoassay with the speed and convenience of fluorescence polarization techniques to provide a means for determining the amount of the specific ligand present in a sample.

Abstract: A device and method for permitting the separation of plasma or serum from whole blood. The device comprises a matrix of hydrophilic sintered porous material to which at least one red blood cell agglutinating agent has been applied. According to a first method of using the device, a sample of whole blood is applied to a first end of the matrix and the red blood cells within the sample come in contact with the agglutinating agents present in the matrix. The blood cells agglutinate, and are entrapped in the interstices of the matrix, while substantially blood-cell-free serum or plasma accumulates near the outlet of the device. A filter means in liquid receiving relationship with the matrix functions to wick the serum or plasma from the matrix.According to an alternative aspect of the invention, a filter means in liquid receiving relationship with the outlet of the matrix functions to retain any blood cells which pass through the matrix is the filter means wicks the plasma or serum from the matrix.

Abstract: Improvements in apparatus for performing an assay to determine the presence or amount of a substance in a test sample, which apparatus comprises means for dispensing one or more reagents from containment means therefor into a reaction vessel and means for dispensing the sample from a sample container into said vessel for reaction with the reagents during performance of the assay, are disclosed. The improvements reside in the apparatus further comprising containment means for the reagents integral and in combination with the sample container and the reaction vessel.

Abstract: A method for preparing chromogenic .alpha.-amylase substrate compounds at substantially high preparative yields in a relatively short period of time by the transglucosylation of a chromogenic glucoside compound to a maltooligosaccharide chain. The concentration of the maltooligosaccharide compound is greater than about 3 times the concentration of the chromogenic glucoside compound to result in at least about 50% of the chromogenic glucoside compound being converted to the desired chromogenic .alpha.-amylase substrate compound.

Abstract: This disclosure relates to a fluorescence polarization immunoassay method for determining C-reactive protein in liquids, especially in biological fluids such as serum, plasma, spinal fluid, amnionic fluid and urine. This disclosure also relates to novel reagents useful in such fluorescence polarization immunoassays.

Abstract: A water-insoluble, crosslinked polyacrylamide copolymer is prepared having recurring monomeric residues of acrylamide, bisacrylamide or analogs thereof, and N,N'-bisacrylylcystamine or analogs thereof. The crosslinked copolymer can be formed into discrete particles having crosslinking disulfide groups on their external surface which can be reduced to provide activated particles having exposed chemically active sulfhydryl groups. The activated polyacrylamide particles are free of residual amino and carboxylic acid groups and can be reacted with suitable haptens and other biologically active substances to provide insolubilized forms thereof.

Abstract: An ion-selective electrode having an electrically insulating substrate with a substantially planar first surface, and having a non-metallic conductor for sensing a potential affixed to the first surface beneath an ion-sensitive membrane. An electrically insulating layer covers at least a portion of the non-metallic conductor and means for making electrical contact with the non-metallic conductor.

Abstract: An immobilized hapten reagent for use in a specific binding assay for the determination of a hapten or binding analog thereof in a liquid test sample and methods for preparing and using the immobilized hapten reagent. The immobilized hapten reagent comprises a hapten moiety covalently linked substantially only to the external surface of a polyacrylamide gel particle. The immobilized hapten reagent is prepared by forming a reaction mixture comprising the hapten moiety and the carrier material in a nonswelling solvent wherein the gel particle is substantially impervious to the hapten moiety and wherein an analytically insignificant amount of the hapten moiety is nonspecifically bound to the gel particle. The immobilized hapten reagent is characterized by being substantially stable in aqueous solutions and exhibits an insignificant amount of leakage of the hapten moiety into a liquid test medium.

Abstract: A method for obtaining a papain-free F(ab').sub.2 antibody fragment preparation derived from papain digested whole IgG antibody employing an antibody to papain for binding to and removing papain-associated digestion products from the preparation. The method is particularly useful for digesting whole IgG antibodies which are otherwise sensitive to pepsin digestion to provide F(ab').sub.2 antibody fragments from which Fab' antibody fragments can be obtained having available free sulfhydryl groups in the hinge region.

Abstract: Chromogenic acridinone enzyme substrate compounds comprising 7-hydroxy-9H-acridin-2-one chromogens derivatized at the 7-hydroxy-position with an enzymatically-cleavable group and disubstituted at the 9-position with alkyl or aryl groups, which can be the same or different, preferably lower alkyl or phenyl, respectively, or together form a cyclohexa-2,5-diene-4-one residue or a 4-hydroxycycloxhexyl residue, and 7-hydroxy-1,3-dihalo-9,9-dimethyl-acridin-2-one intermediates useful for the preparation of the novel chromogenic acridinone enzyme substrate compounds and methods therefor.

Abstract: A multizone test device for the determination of analyte from a liquid test medium upon contact with the liquid test medium and a labeled reagent comprising a chemical group having a detectable physical property. The test device preferably comprises multilayers including a reagent layer incorporated with an immobilized reagent and a detection layer incorporated with an immobilized form of a binding substance for the labeled reagent. The immobilized reagent and the labeled reagent comprise specific binding partners which will bind to each other dependent upon the amount of analyte present. Labeled reagent which does not become bound to the immobilized reagent in the reagent layer migrates into the detection layer and becomes bound to and immobilized by the immobilized binding substance therein.

Abstract: A multizone test device for the determination of analyte from a liquid test medium upon contact with the liquid test medium and a labeled reagent comprising a chemical group having a detectable chemical property. The test device preferably comprises multilayers including a reagent layer incorporated with an immobilized reagent and a detection layer incorporated with an immobilized form of an interactive detection reagent for the labeled reagent. The immobilized reagent in the reagent layer and the labeled reagent comprise specific binding partners which will bind to each other dependent upon the amount of analyte present. Labeled reagent which does not become bound to the immobilized reagent in the reagent layer migrates into the detection layer and interacts with the immobilized interactive detection reagent therein which results in the localized generation of a detectable reaction product which preferably is also immobilized in the detection zone.

Abstract: Procainamide and N-acetylprocainamide (NAPA) immunogens, antibodies prepared therefrom, labeled conjugates, synthetic intermediates, and the use of such antibodies and labeled conjugates in immunoassays for determining the respective drugs. The immunogens comprise the drugs coupled at the .alpha.-position of the amide side chain to an immunogenic carrier material. The labeled conjugates and synthetic intermediates similarly are .alpha.-position derivatives of the drugs or precursors thereof. The antibodies and labeled conjugates are particularly useful in homogeneous nonradioisotopic immunoassays for measuring the respective drugs in biological fluids such as serum.

Abstract: Fluorogenic indicator compounds responsive to the presence of hydrogen peroxide and methods and test compositions for determining hydrogen peroxide in a test sample. Preferred indicator compounds are 3,4-dihydrocoumarin derivatives and 3,4-dihydro-2-quinolone derivatives, especially those having a dialkylamino group at the 7-position. Such particularly preferred compounds are of the formula: ##STR1## wherein R.sup.1 is hydrogen, cyano, or --COOR.sup.6, --CONHR.sup.6 or --CON(R.sup.6).sub.2 where R.sup.6 is hydrogen, alkyl, alkenyl, or aryl; R.sup.3 and R.sup.4 are lower alkyl; and Y is .dbd.0 or .dbd.N--R.sup.5 where R.sup.5 is hydrogen or lower alkyl. The indicator compounds yield highly fluorescent products upon oxidation by hydrogen peroxide in the presence of a peroxidatively active substance and are useful in analytical systems which generate hydrogen peroxide in response to an analyte under determination in a test sample.

Abstract: Optical indicator chalcogen (selenide or sulfide) compounds responsive to oxidants, e.g., hydrogen peroxide, and methods for preparing and using such indicators. Upon oxidation the resulting intermediate undergoes spontaneous elimination of the chalcogen residue to yield a signal compound which provides an optical signal such as fluorescence. Preferred fluorogenic indicator compounds are 3-chalcogen-3,4-dihydrocoumarin derivatives and 3-chalcogen-3,4-dihydro-2-quinolone derivatives. Such indicator compounds provide highly fluorescent products upon oxidation by hydrogen peroxide and are useful in analytical systems which generate hydrogen peroxide in response to the analyte under determination.

Abstract: A heterogeneous specific binding assay method for determining the amount of a suspected analyte in an aqueous test medium wherein a reaction mixture is formed by combining the test medium with assay reagents including a labeled reagent, an immobilizable component, and a binding substance which causes the immobilizable component to precipitate. Free and bound species of the labeled reagent are formed as a function of the amount of the analyte in the test medium. One of the free and bound species of the labeled reagent is immobilized by binding of the immobilizable component with the binding substance. The immobilized labeled reagent is seperated from labeled reagent which has not been immobilized, and the amount of label in the labeled reagent in one of the separated fractions is determined and related to the amount of analyte in the test medium.

Abstract: A method for the quantitative determination of lithium in a liquid test sample employing turbidimetric or nephelometric techniques to measure the maximum rate of change in the optical density of a reaction mixture containing precipitated lithium. The lithium is precipitated by a lithium precipitating reagent to result in dispersed, suspended particles, and the maximum rate of change in optical density determined to provide a linear dose response which can be quantitatively correlated to the amount of lithium present in the test sample.