Abstract: A stable test device capable of manufacture by automated methods for the determination of chloride in an aqueous fluid sample. The test device operates by controlled diffusion of the aqueous sample into a porous matrix. The matrix is incorporated with sodium carrageenan and silver salts capable of dissolving in an aqueous fluid containing chloride, at least part of which silver salts is silver chromate. Devices prepared with the inclusion of sodium carrageenan provide a chloride test device with approximately double the shelf life under room temperature storage conditions of previous test devices prepared without sodium carrageenan. The stable test device provides useful information in less than about 2 minutes after the sample contacts the matrix. The chloride concentration of the sample is determined by comparing the pattern of silver chromate remaining after sample contact to an appropriate pattern chart.

Abstract: A test means for determining the presence of an ion in an aqueous test sample, a method for preparing it and a method for using it. The test means comprises a hydrophilic carrier matrix incorporated with finely divided globules of a hydrophobic vehicle. The hydrophobic vehicle contains an ionophore capable of forming a complex with the ion and a reporter substance capable of interacting with the complex of ionophore and ion to produce a detectable response. The test means of this invention is useful for clinical determinations of serum potassium. The test means forms the reagent layer in a multilayer format which is particularly suited to whole blood electrolyte determinations and does not require washing or wiping before use.

Abstract: A viability test device wherein the viability of a test composition for the determination of an analyte of interest can be determined by simply wetting the device with ordinary water. The viability device can be prepared in three formats: a control or calibrator device, an internal control device and a self indicating device. Unreacted analyte, or an analog thereof, can be incorporated in a limited defined portion of a dried carrier matrix incorporated with a test composition to provide an internal control test device. When wetted with water, a positive optical response, usually color, indicates the test composition can provide a viable test for the analyte. The internal control test device is particularly advantageously used by diabetics in their own homes where a negative test response could be due to the desired control of the user's condition or due to deterioration of a test composition because of unfavorable storage conditions.

Abstract: A test composition comprising glucose oxidase, a peroxidatively active component, a chromogenic indicator system capable of providing a detectable response and a borate buffer capable of providing an initial pH above about pH 7 is particularly useful for the semiquantitative determination of high range glucose, (i.e. glucose concentrations of 1,000 mg/dL to 10,000 mg/dL). A preferred indicator system is a water soluble iodide salt and poly(vinylpyrrolidone). The use of a borate buffer capable of providing an initial pH above about pH 7 permits greatly improved resolution for the semiquantitative determination of high range glucose when the test composition is incorported onto a carrier matrix to prepare a solid state unitary test device.

Abstract: A composition, device and method useful as an enzymatic urea assay based on the use of urea amidolyase comprising urea amidolyase, pyruvate kinase, pyruvate oxidase, mono and divalent cations, phosphoenolpyruvate, thyamine pyrophosphate, ATP, bicarbonate, phosphate, a color indicator system and optionally inorganic phosphate, a buffer having a pH range of from about 6.5 to 9.5, and sodium or potassium ferrocyanide. After contacting the test solution or body fluid sample with the assay composition, reading can be accomplished visually or instrumentally.

Abstract: The invention provides a flavin adenine dinucleotide (FAD) synthetase preparation with a specific activity at 25.degree. C. greater than at least 75 nanomoles per minute per milligram of protein in the preparation and usually greater than at least 150 nanomoles per minute per milligram of protein in the preparation as measured utilizing flavin mononucleotide (FMN) as the substrate. The purified preparation is obtained by disrupting a cellular source of FAD synthetase activity, precipitating the protein and separating an FAD synthetase active fraction by column chromatography. FAD synthetase catalyzes the reaction of adenosine triphosphate and flavin mononucleotide to flavin adenine dinucleotide and pyrophosphate, among others.

Abstract: A composition, test means (and device) and method for determining peroxidatively active substances in a test sample are disclosed. The composition, test means (and device) and method are rendered resistant to the adverse affects of ascorbate which may be present in the sample by the inclusion in the composition of a metal chelate which is polycarboxyalkylamine derivative having the formula: ##STR1## where: (a) R.sub.1 is hydrogen or straight or branched chain alkyl alcohol or alkyl carboxylic acid radicals having from 2 to 3 carbon atoms; R.sub.2, R.sub.3, R.sub.x and R.sub.y, same or different, are straight or branched chain alkyl alcohol or alkyl carboxylic acid radicals having from 2 to 3 carbon atoms; where at least two of R.sub.1, R.sub.2, R.sub.3, R.sub.x or R.sub.y are alkyl carboxylic acid radicals so defined;(b) R.sub.p and R.sub.

Abstract: A test composition, device and method for determining a perioxidatively active substance in a test sample, as well as a method for preparing and using the device, are disclosed. The composition comprises an organic hydroperoxide, a benzidine indicator capable of providing a detectable response in the presence of the organic hydroperoxide and a peroxidatively active substance, and, as a stabilizing agent, an aniline chosen from pheny-1-naphthylamine, N,N-dimethylaniline and mixtures thereof. The device comprises a carrier matrix incorporated with the composition, and the method for using the device comprises contacting a test sample with the device and observing a detectable response therein. A method for preparing the device comprises preparing two or more solutions of the ingredients of the composition, wetting the carrier matrix sequentially therewith and drying the matrix after each wetting.