Abstract: A spectrophotometric assay for the detection of acetaminophen in aqueous fluids is carried out with a dry analytical element. The element comprises a support having thereon one or more reagent layers containing a first enzyme, aryl acylamidase, to cleave the amide bond of acetaminophen to produce p-aminophenol; and a mild oxidizing agent to oxidize the p-aminophenol so that it couples to a water-soluble coupling agent to form a dye that is read at 670 nm. The assay is precise, accurate on serum and plasma samples, and relatively free from significant interferences. The element also allows measurement over a broad dynamic range.

Abstract: A dry analytical element is disclosed which can be used to sensitively and rapidly detect and quantitate protein. The assays are carried out using a dye that reacts with protein and molybdate ion to produce a measurable change in the spectral absorption of the dye. Also disclosed are polymers which stabilize and enhance the accuracy of the assay, and compounds which reduce interference by bicarbonate.

Abstract: A dry analytical element has been prepared for the assay of leucine aminopeptidase at a pH of 6.5 to 11. The element zone contains an aromatic substrate for the enzyme. This substrate provides an aromatic reactant which has a primary amino group on the aromatic ring in the ortho or para position to an electron donor group. The aromatic reactant is oxidized with an oxidizing compound (such as an oxidase) and the oxidized compound reacts with a ballasted color-forming coupler to provide a dye.

Abstract: An extraction composition is useful for lysing chlamydial, gonococcal or herpes organisms and extracting detectable antigen from the organisms. In particular, this composition has a high pH (at least about 8) and comprises an alcoholamine which is effective in extracting antigen. It is particularly useful for extracting either or both of the lipopolysaccharide and major outer membrane protein chlamydial antigens.

Abstract: An extraction method for lysing chlamydial, gonococcal or herpes organisms and extracting detectable antigen therefrom involves the use of a protease. In particular, the antigen can be effectively extracted from a biological specimen which contains whole blood or mucous using a protease. The extracted antigen can be effectively detected in an immunoassay involving antibodies directed to the antigen. The protease is novel to the process and is obtained from Bacillus subtilisin.

Abstract: Antigens from chlamydial organisms in specimens can be rapidly and sensitively determined using a polyamide microporous membrane which has surface hydroxy groups. This determination is accomplished by contacting extracted antigen with the polyamide microporous membrane for a sufficient time for the antigen to bind to the membrane. Antigen bound to the membrane is contacted with chlamydial antibody so as to form an immunological complex on the membrane. The presence of the complex on the membrane in then determined as a measure of the amount of chlamydial antigen present in the specimen. The use of this particular membrane improves reagent keeping and reduces background in the assay.

Abstract: A composition including a sulfhydryl-containing reducing agent is stabilized for long term storage with a hydrophilic polymer. This composition can be combined with one or more reagents useful for extracting antigens from chlamydial or gonococcal organisms. The extracted antigen can be determined using immunological reactions and appropriate labeled reactants.

Abstract: Dry transparent analytical elements can be used to determine analytes which have been separated by electrically induced migration through a solid medium, e.g. by electrophoresis, or which are intracellular enzymes. The dry transparent element is placed on a plate containing the analytes, and kept there until the analytes have reacted to produce a non-diffusible detectable species solely in the element. The element is removed and the detectable species is evaluated therein. The elements contain a water-insoluble binder material having an interactive composition dispersed therein which reacts with analyte to produce the non-diffusible species. The same electrophoretic plate can be used to successively determine the same or a plurality of analytes since it is not altered or destroyed by contact with the dry element.

Abstract: Antigens from chlamydial or gonococcal organisms in specimens containing whole blood, mucus or components thereof can be rapidly and sensitively determined using a polyamide microporous membrane which is coated with a surfactant. This determination is accomplished by contacting extracted antigen with the coated polyamide microporous membrane which is substantially free of any particulate matter. The membrane has an average pore size of from about 1 to about 10 .mu.meter. Within about 10 minutes of that contacting, antigen bound to the coated membrane is contacted with chlamydial or gonococcal antibody, respectively, so as to form an immunological complex on the membrane. The presence of the complex on the membrane is then determined as a measure of the amount of chlamydial or gonococcal antigen present in the specimen.

Abstract: An analytical element can be used for the determination of either creatinine or creatine or both. The element contains creatinine amidohydrolase, creatine amidinohydrolase and sarcosine oxidase, and a leuco dye which is capable of providing a detectable dye in the presence of hydrogen peroxide and a peroxidative substance. The creatine amidinohydrolase is present in a manner such that it is substantially inert to the leuco dye. The creatinine amidohydrolase is present in a rate limiting amount. By measuring the amount of dye formation at particular times during the assay, either or both of the analytes can be determined with the same element.

Abstract: A dry multilayer analytical element for determination of total ionic iron is disclosed. The element includes a dye which complexes with Fe.sup.+2. The dye has the structure ##STR1## R.sup.1 represents an electron donating group; or R.sup.1, together with the carbon to which it is attached, represents sufficient atoms to form a cyclic electron donating group fused to the phenyl group to which R.sup.1 is attached;R.sup.2 represents an electron withdrawing group; andR.sup.3 represents H, Cl, F, Br or OR.sup.4 wherein R.sup.4 represents a hydrocarbon having from 1 to 20 carbon atoms.

Abstract: There is disclosed a method for quantitatively determining protein, comprising the steps of:(a) providing a sample of the protein in an aqueous medium;(b) providing an aqueous medium having a pH in excess of 12 and comprising(i) a cupric salt and a pyridyl-azo dye; or(ii) a preformed cupric-pyridylazo dye complex;(c) combining the aqueous mediums of a) and b) thereby providing a color having an intensity which is inversely proportional to the amount of unreacted dye present in the combined mediums; and(d) determining the quantity of protein present in the sample colorimetrically.The method can be used with a multilayer dry analytical element.

Abstract: An analytical element is used to determine magnesium ions at a pH of from about 8.5 to about 11. This element comprises an absorbent carrier material containing a 1,5-bis(2-hydroxyphenyl)-3-cyanoformazan compound which is substituted in at least one of the 3-, 4- and 5-positions of either phenyl moiety. The substituents are chosen such that their cumulative Hammett-sigma value is greater than about 0.23, provided that none of the substituents is carboxy. The assay is carried out in the presence of a calcium ion chelating agent and a suitable buffer. In preferred embodiments, the cyanoformazan is incorporated in the element in such a manner so as to be isolated from protein molecules which may be encountered in the assay.

Abstract: A method for the determination of the amount of lipase in a sample comprises the steps of:(a) contacting the sample with a reagent composition comprising:(i) a lipase substrate which is a glycerol triester oil having in one of its two .alpha.-ester positions a long chain alkyl group having at least 8 carbon atoms and, in its two remaining ester positions, short chain alkyl groups such that, if the long chain alkyl group is hydrolyzed, the resulting diester is water soluble; and(ii) an esterase enzyme capable of catalyzing the hydrolysis of a water soluble glycerol diester to glycerol; and(b) detecting the rate at which glycerol is formed.The compositions of the present invention include the substrate and enzyme as defined. The element of the invention comprises a support having thereon the described composition. The invention is useful for determining lipase in samples which contain endogenous glycerol, such as blood serum and other body fluids.