Abstract: A test device for determining the analyte concentration in body fluid. The test device has a memory in which calibration adjustments corresponding to calibration numbers are stored. The test device is adapted to receive a test sensor for collecting a sample. The test sensor contains a reagent adapted to produce a reaction indicative of the analyte concentration in the sample and the test sensor has an associated calibration number of a plurality of digits. The test device comprises a measuring unit, a single calibration input element, a user display, and a processor. The measuring unit measures the reaction of the reagent and the analyte and generates a signal indicative of the measured reaction. The single calibration input element permits a user to input the calibration number, one digit at a time, associated with the test sensor. The processor is adapted to determine the analyte concentration.

Abstract: A test device for determining the concentration of an analyte in body fluid is disclosed according to one embodiment of the present invention. The test device has a memory in which a plurality of calibration adjustments corresponding to a plurality of calibration numbers are stored. The test device is adapted to receive a test sensor for collecting a sample, wherein the test sensor contains a reagent adapted to produce a reaction indicative of the concentration of the analyte in the sample and the test sensor has an associated calibration number of a plurality of digits. The test device comprises a measuring unit, a single calibration input element, a user display, and a processor electronically coupled to the single calibration input element, the measuring unit, and the user display. The measuring unit measures the reaction of the reagent and the analyte and generates a signal indicative of the measured reaction.

Abstract: The glucose concentration in a whole blood sample may be determined by providing an electrochemical sensor adapted to measure glucose and hematocrit concentrations. The hematocrit concentration of the whole blood sample is measured using the electrochemical sensor via electrochemical impedance spectroscopy. The initial glucose concentration of the whole blood sample is measured using the electrochemical sensor. The unbiased glucose concentration in the whole blood sample is calculated using the initial glucose concentration measurement and the hematocrit concentration.

Abstract: Apparatus and method are provided for determining the concentration of an analyte in a fluid test sample by applying the fluid test sample to the surface of a working electrode which is electrochemically connected to a reference electrode which surface bears a composition comprising an enzyme specific for the analyte. A mediator is reduced in response to a reaction between the analyte and the enzyme. An oxidizing potential is applied between the electrodes to return at least a portion of the mediator back to its oxidized form before determining the concentration of the analyte to thereby increase the accuracy of the analyte determination. Following this initially applied potential, the circuit is switched to an open circuit or to a potential that substantially reduces the current to minimize the rate of electrochemical potential at the working electrode. A second potential is applied between the electrodes and the current generated in the fluid test sample is measured to determine analyte concentration.

Abstract: Apparatus and method are provided for determining the concentration of an analyte in a fluid test sample by applying the fluid test sample to the surface of a working electrode which is electrochemically connected to a reference electrode which surface bears a composition comprising an enzyme specific for the analyte. A mediator is reduced in response to a reaction between the analyte and the enzyme. An oxidizing potential is applied between the electrodes to return at least a portion of the mediator back to its oxidized form before determining the concentration of the analyte to thereby increase the accuracy of the analyte determination. Following this initially applied potential, the circuit is switched to an open circuit or to a potential that substantially reduces the current to minimize the rate of electrochemical potential at the working electrode. A second potential is applied between the electrodes and the current generated in the fluid test sample is measured to determine analyte concentration.

Abstract: A method for separation of erythrocytes from whole blood by diluting the whole blood with saline and introducing low concentrations of soluble salts of trivalent cations into the diluted blood sample.

Abstract: An assay for the detection of a peroxidatively active substance in a test sample. The assay employs a phenylenediamine and a naphthol which, under the conditions of the assay, couple to form a chromogen thereby indicating the presence of the analyte. The assay is carried out at a pH of from 10 to 14 since false positives due to ascorbate interference are minimized in highly alkaline media.

Abstract: The present invention is directed to a simple and inexpensive liquid or dry reagent assay system for detecting nanomolar amounts of manganese in body fluids in microgram per liter concentrations. More specifically, the manganese assay of this invention is directed to the optical detection of a chromogenic reaction, such as the oxidation of a redox indicator, catalyzed by a manganese porphyrin complex.

Abstract: A process and device for quantitative determination of analyte concentrations in liquid samples. The device includes one or more bibulous matrices constructed and arranged to essentially eliminate sample volume sensitivity from analyte determinations. In accordance with the present invention, the device includes one or more test reagent-treated bibulous matrices covered at least partially by an impermeable coating or film. A liquid sample is applied to the uncovered portion of the bibulous matrix such that the liquid sample is metered into the bibulous matrix by the impermeable coating or film. The sample chromatographs through the bibulous matrix until the matrix is saturated with liquid. The process is essentially sample volume independent, providing more uniform and accurate quantitative analyte determinations.

Abstract: The precision in reflectance or absorption measurements used to determine the presence and concentration of a component in an assay liquid is unexpectedly increased to essentially eliminate the variability of different reactant carriers and variability in reflectance or absorption instruments by including, either within the reactant carrier or within the assay liquid sample, in addition to a primary color forming or color changing indicator, a secondary inert colorant compound or dye having a light absorption wavelength peak separated from a light absorption wavelength peak of the primary indicator or chromogen by at least 80 nm. To achieve the full advantage of the present invention, the colorant material or marker should be inert to the reactant system in the carrier and should be inert to the assay liquid to provide a light reflectance or light absorption response essentially distinct from the light reflectance response of the primary chromogen to compensate for measurement variability.

Abstract: Glucose indicator, test means and method for assaying glucose in fluids are disclosed. More specifically, a new indicator formulation comprising an enzyme system which includes a substance having glucose oxidase activity, a substance having perioxidative activity and a mixture of syringaldazine and 3,3',5,5'-tetramethylbenzidine are disclosed for indicating the presence of glucose in industrial and body fluids. The indicator formulation is nonmutagenic and can be used in conjunction with instrumentation designed to quantitatively measure whole blood glucose levels within the range of 10 to 400 milligrams (mg) per 100 milliliters (ml).