Abstract: A chain incubator or conveyor, and method of use in an analyzer, wherein an endless chain is formed of repeating members and each comprising a link, element support, a cover, and means for biasing the cover onto the support with an article such as a test element between them. The members are linked together by a pair of pivot pins, and the chain is engaged by a drive sprocket and an idler sprocket.

Abstract: An aspirator/dispenser of liquid has a sensor for sensing contact with the liquid by the dispense vessel, which uses constant pressure air expelled out the tip of the dispense vessel. The sensor is improved in that the line of air pressure feeding into the vessel is vented in parallel with the vessel, to the atmosphere, so that the spike of pressure occurring when the vessel encounters the liquid, is released out the vent, rather than the vessel, thus avoiding bubble formation in the liquid.

Abstract: A method of separating bound labeled indicator from free labeled indicator in a layer of a test element for immunoassay. The method comprisesa) depositing sample containing a target immunoanalyte capable of binding to the labeled indicator or to an immobilized antibody in competition with the labeled indicator, onto an exterior surface of a test element in the presence of the labeled indicator andb) adding an amount of wash liquid to the exterior surface to form a pool of the liquid having a meniscus on the surface, the liquid penetrating the surface over an area bounded by a closed intersect edge formed between the pool meniscus and the surface, so that penetrating liquid can push free labeled indicator away from bound labeled indicator in a volume of the layer below the bounded area.

Abstract: A method and apparatus for forming in situ a new disposable tip for a dispensing probe within an analyzer, by feeding a continuous stock of tube through two die plates and severing the tube by relative motion of the die plates, while holding the cut portion in the dispensing probe temporarily inserted into one of the die plates. The tip is ejected from the probe in a direction opposite to the direction of insertion of the tube into the die plates and dispensing probe.

Abstract: A method of dispensing wash solution to separate free from bound labels in a slide immunorate assay. The method comprises dispensing wash first as separate drops spaced to allow complete absorption prior to the next drop, followed by a time at which the rate of dispensed wash exceeds the rate of fluid uptake of the slide, to form a continuous stream. The first phase of this wash method provides a more complete separation of bound from free under the dispense tip than occurs if only a continuous stream is used throughout.

Abstract: A holder of slide test elements for use in an analyzer at a sample-dispensing station, the holder comprising two opposing holding surfaces for holding generally horizontally a slide test element at opposite side edges of the test element, and a tower extending above the holding surfaces for generally centering a dispensing tip above a held slide test element. The holder is improved in that one of the holding surfaces of the holder extends at least sufficiently for underneath a slide test element held by the holding surfaces to be disposed under an approximate center of the held test element, and includes a raised reference surface located under, and disposed for abutting against, an under-surface of the held slide test element, so that a held slide test element is prevented by the raised reference surface from warping downwardly away from a dispensing tip in the tower.

Abstract: A centrifuge and method of operating it, wherein a patient sample tube is first spun while non-aligned with the centrifugal force to make use of the Boycott effect, and then while aligned with the centrifugal force to allow any gel present between the separated phases to properly seal. A latch is used to hold it in the non-aligned position until the latch is opened.

Abstract: There is disclosed a closure mechanism for two reagent bottles in a bottle holder of an analyzer, using a shutter that slideably and frictionally engages the top surface of grommets at the mouth of the bottles. The shutter slides to either an open or closed position of the bottles, either both in lock-step or with one bottle open, the other closed, and both closed together. The shutter is driven by a cam and cam followers, either rotationally or linearly.

Abstract: An array of tips is disclosed for multiple loading onto plural aspirators, wherein the array comprises columns of tips temporarily joined together within and between columns, at discontinuously spaced junctions. The array is moved along in tracks spaced so as to diverge when tip columns are to be broken out of the array. Each track ends in a step-down ledge that allows an aspirator to punch an engaged tip out of its column.

Abstract: A method for reducing interferent bias such as hemoglobin bias in immunoassays using dried slide test elements featuring peroxidase and leuco dye as the labeling mechanism.

Abstract: A conveyor and a method of providing a reaction cuvette using a conveyor, wherein a sensor is included to sense whether more than one cuvette is being conveyed. Because the cuvettes are received from a stack, one at a time, the sensor determines if two stacked cuvettes are present on the conveyor instead of one, by sensing the presence or absence of a cuvette projecting above the top of the desired cuvette.

Abstract: A heating assembly useful in apparatus for processing reaction cuvettes for replicating specified DNA sequences, such as those using PCR, having a heating element with a heat delivering surface for compressively contacting a pliable fluid-carrying compartment of a supported cuvette. The heat delivering surface has a defined passage sized to allow the detection compartment to be situated therein so that the compartment can be efficiently heated. Fluid flow through the compartment, however, is not interfered with during the heating process due to the presence of the defined passage. In addition, the heat delivering surface can be made from optically transparent materials so that visual detection within the processor can take place.

Abstract: A method and kit are disclosed for recalibrating a factory-prepared relationship between concentration and expected signal R.sub.exp produced by an analyzer. The method and kit use two or three calibrators at the field to obtain an actual signal R.sub.act for the two calibrators C.sub.low and C.sub.high, for example, and these two actual signals are used to create a ratio of R.sub.actlow /R.sub.explow and R.sub.acthigh /R.sub.exphigh. The first of these is used to correct the expected signals for concentrations below the lower calibrator concentration, and the second is used to correct expected signals for concentrations above the higher calibrator concentration, producing pseudosignals PS.sub.low and PS.sub.high. A straight-line relationship is applied between the corrected PS.sub.low and PS.sub.high, and that relationship is used for concentrations between C.sub.low and C.sub.high.

Abstract: A wide bandwidth slope detector has a comparator with first and second time constant circuits coupled to first and second inputs thereof. Where one time constant is on the order of three times the other, the comparator will change state in response to the slopes of an input analog signal coupled to the time constant circuit. Feedback can be provided by a fixed resistor or by a tracking circuit. A smoothing or clipping circuit can be used to pre-process the input analog signals to eliminate noise therefrom. A bar code reading system combines first and second clipping circuits to smooth the highs and lows of the input signal, coupled to a slope detector. The tracking circuit can be used to provide a symmetrical hysteresis characteristic.

Abstract: An ion-junction fibrous bridge and a potentiometric test element incorporating the same, wherein the fibers extending generally along the center-line between two liquid access apertures in the bridge, are readily capable of conducting aqueous liquid through the bridge, and fibers extending at an angle of at least 20 .degree. from said center-line are not readily capable of conducting aqueous liquid.

Abstract: There is disclosed a slide test element and method of assay that allows for detection of analytes in biological liquids without the use of any detection reagents. The method uses NIR spectroscopy and a test element comprising a support, and a substantially constant light-path defining layer comprising a diffusely-reflecting material that is a) sufficiently porous in all directions as to allow a liquid to spread uniformly in all directions, and b) homogeneously reflects at least 95% of NIR radiation.

Abstract: A wide bandwidth slope detector has a comparator with first and second time constant circuits coupled to first and second inputs thereof. Where one time constant is on the order of three times the other, the comparator will change state in response to the slopes of an input analog signal coupled to the time constant circuit. Feedback can be provided by a fixed resistor or by a tracking circuit. A smoothing or clipping circuit can be used to pre-process the input analog signals to eliminate noise therefrom. A bar code reading system combines first and second clipping circuits to smooth the highs and lows of the input signal, coupled to a slope detector. The tracking circuit can be used to provide a symmetrical hysteresis characteristic.

Abstract: A wide bandwidth slope detector has a comparator with first and second time constant circulars coupled to first and second inputs thereof. Where one time constant is on the order of three times the other, the comparator will change state in response to the slopes of an input analog signal coupled to the time constant circuit. Feedback can be provided by a fixed resistor or by a tracking circuit. A smoothing or clipping circuit can be used to pre-process the input analog signals to eliminate noise therefrom. A bar code reading system combines first and second clipping circuits to smooth the highs and lows of the input signal, coupled to a slope detector. The tracking circuit can be used to provide a symmetrical hysteresis characteristic.