Abstract: Test compositions and test devices are provided which are capable of generating different hues at different analyte concentrations. Visual results for clinically important analytes, such as glucose and cholesterol, are provided by use of compositions containing two independent catalytic systems which are reactive with a common substrate generated from the analyte of interest, to produce visual endpoints of different hues for different concentrations of analyte. Preferred formulations provide a RAINBOW of hues, the particular final hue produced depending on the concentration of the analyte.

Abstract: Test devices are disclosed which are useful for determining glucose or occult blood comprising a carrier matrix, glucose oxidase, an indicator system and a glucose derivative that upon addition of water hydrolizes to produce glucose.

Abstract: The invention relates to new dicyanoethylaryl derivatives and to processes for their preparation. The compounds according to the invention can be used as redox indicators, such as, for example, for the detection of hydrogen peroxide with the aid of peroxidases or peroxidatively active substances.These redox indicators are futhermore suitable for the detection of peroxidases or peroxidatively active compounds, it also being possible to use other peroxides as oxidizing agents.

Abstract: An assembly for separating, metering and delivering fluids includes a central rotating member rotatable about a fixed spin axis. A processing chamber holding member is connected to the central rotating member by a centrifugally actuated frame. At rotational speeds below a first predetermined speed, the centrifugally actuated frame is in a first position. At rotational speeds greater than the first speed, centrifugal force moves the frame to a second position angularly spaced from and at greater distance from the spin axis than the first position. A processing chamber is mounted on the holding member and its orientation relative to the spin axis is the same in the first and second positions. Fluid is provided in the processing chamber. By accelerating the processing chamber to the first predetermined speed and decelerating below the first predetermined speed in a selected sequence, specific centrifugal force vectors are generated in the processing chamber that move the fluid and retain it in selected chambers.

Abstract: A reflectance photometer for quantitatively measuring diffuse light includes a light source located above a sample. The reflectance photometer also includes a first detector mounted at a preselected scattering angle relative to an axis extending perpendicularly from the sample through the light source. A first linear polarizer is mounted between the sample and the light source. The direction of polarization of the first linear polarizer is vertical to a scattering plane defined by the direction of incoming light from the light source and the direction of reflected light detected by the first detector. A second linear polarizer is mounted between the sample and the first detector. The direction of the second polarizer is parallel to the scattering plane. The reflectance photometer can include a second detector mounted at a second, scattering angle. A third linear polarizer is mounted between the sample and the second detector.

Abstract: A soft package fabricated of a material with a memory is tested by placing the package in a vacuum. If there are no leaks in the package, the package undergoes a dimensional change as the vacuum is created. This dimensional change can be measured. If no dimensional changes occurs, the package has a gross leak. If the package increases in dimension and then gradually returns to its original shape, a slow leak exists. If the package grows in dimension upon creation of vacuum and retains that dimensional growth, there is no leak in the package. A test fixture for measuring the dimensional changes includes a base plate on which a package may be positioned. A support member is mounted on the base plate to support a plunger rod for reciprocal movement relative to the base plate. The plunger includes a first end that engages the package to be tested and a second end on which a platform is mounted. A counterweight is positioned onthe platform.

Abstract: Electrically conducting homo- and/or copolymers and/or tripolymers can be produced from novel monomers, such as a 3-substituted 2,5-di(2-thienyl)pyrrole. The polymers exhibit unexpectedly high stability and conductivities, and can be functionalized, such as with an enzyme, like glucose oxidase, or an ion-specific binding site, like a crown ether, or an antigen, without adversely affecting the conductivity of the polymer. The functionalized, conducting polymer can be used in a diagnostic device to determine the presence and concentration of a specific analyte in a liquid medium.

Abstract: The invention involves visual determination of hydrogen peroxide with a multiple oxidative indicator system capable of generating different hues at different concentrations of hydrogen peroxide or at different concentrations of an analyte from which hydrogen peroxide is generated by means of an analyte specific oxidase. A first indicator component of the multiple oxidative indicator system is oxidized from a particular hue to a different hue which is preferably essentially colorless. A second indicator component is oxidized to a hue which is visually distinct from the first indicator component in either of its hues. A third indicator component may also be present which is oxidized to provide a colorimetric response. Each component is oxidized only by hydrogen peroxide and peroxidase.

Abstract: Process for the production of a test devices using extruder casting machines or cascade casting machines is disclosed in which reagent zones are produced on a common surface with remaining portion of test device such that reagent zone is protected by being in the same plane as a portion of the test device. The process permits application of reagent material to matrix areas without interaction of the reagents or the loss of reagents due to extraction during the process of forming the test device.

Abstract: A quantitative measuring instrument includes a casing with a cavity for a reagent strip handling mechanism. The mechanism includes a slide with a resiliently biased toggle member for providing snap action of the slide between an open, reagent strip loading position and a closed, quantitative measuring position. A light seal is mounted on the toggle member that engages each reagent strip in the closed position of the slide. In a first, alternative embodiment of the instrument, the slide mechanism includes a cam arm that engages cam surfaces on the instrument raising the cam arm to an open, reagent strip loading position from a closed, reagent strip holding position. In this embodiment the slide can be removed from the instrument and cleaned. In a second alternative embodiment the slide includes a first detent corresponding to a closed position of the slide and a second detent corresponding to an open position. A pair of spring fingers are mounted in the cavity of the instrument casing.

Abstract: A slow start motor control circuit for applications wherein extremely accurate speed control is required, such as, in a centrifugal blood separator application is disclosed. In a blood separator, the degree of separation of cellular components, such as red blood cells and platelets, from the blood plasma is a function of the rotational speed of the centrifuge and the spin time. The control circuit controls the spin time and the rotational speed of the drive motor by controlling the voltage applied to the motor. The control circuit allows the drive motor to start relatively slowly to avoid cell breakage which can contaminate the plasma. After the centrifuge attains its desired operational speed, the speed of the motor is regulated and is relatively uninfluenced by ambient temperature variations.

Abstract: A clock circuit for a microcomputer having a clock input, a halt mode state output and an interrupt input, comprises: a clock pulse generator having an output, a switch for applying a pulsed output to the interrupt input of the microcomputer to indicate a start of operation; a latch receptive of the output of the switch to change from a first state to a second state, gates receptive of the output of the clock pulse generator and the latch for applying clock pulses to the microcomputer when the logic is in the second state and preventing the application of clock pulses to the microcomputer when the logic is in the first state and circuitry for applying the halt mode state output to the logic circuit to disable same from the second state to the first state.

Abstract: A device for measuring transmittance of light comprises a light source, photodetector and signal processor. The concentration of a substance in a fluid sample can be accurately determined by coating the light source with a reagent that is chemically reactive with the substance and measuring light transmitted from the coating before and after the substance is applied to the coating. The coating can contain a solid support matrix, such as a translucent nonwoven paper web of the type used in reagent test strips and similar indicator devices. The invention is useful for making clinical analyses on body fluids.

Abstract: A multiple reagent test strip-reading instrument having rails extending from a loading area to one or more reading station platforms and then to a waste receptacle, a reciprocating blotter arm which contacts individual reagent strips sequentially placed transversely on the rails in the loading area, moving individual strips along the rails to an indexing strip advancing mechanism which intermittently advances the strips along the rails in spaced parallel relation, and after each advance, allows the strips to dwell for a predetermined time period; individual test strips being thereby sequentially delivered to reading position on the reading station platform where, during the dwell period, they are read by reflectance photometry. After reading, the strips are moved to the waste receptacle.

Abstract: A two-piece slide dispenser includes a housing defining an internal compartment for the storage of a plurality of reagent slides or similar items. The housing includes a dispensing opening and a loading opening. A finger or similar structure at least partially obstructs the dispensing opening to prevent inadvertant falling out of the reagent slides. A one-piece, multiple function, resilient spring boot including a biasing portion and a light and humidity sealing portion is also provided. Once reagent slides are loaded through the loading opening into the internal compartment, the spring boot is mounted in the compartment to engage the slides biasing them toward the dispensing opening. The biasing portion of the spring boot can be hemispherical or of a similar configuration allowing this portion to fold into itself. The biasing portion also includes an extension extending from the hemisphere to engage the slides.

Abstract: The present invention relates to new chromogenic amino acid esters and peptide esters of hydroxyisoquinolines and hydroxyquinolines, processes for their preparation and the use of the new esters as substrates for the analytical detection of esterolytic and/or proteolytic enzymes, for example in body fluids, the esters being incorporated into test agents, in particular test strips, in a suitable manner. The new esters are particularly used for the detection of leukocytes, in particular in urine.