Abstract: One method and apparatus for analyzing clotting characteristics of a blood sample includes the use of a non-linear equation having coefficients capable of being related to the underlying clotting processes. The non-linear equation is curve fit to a waveform of a clotting sample to provide values for the coefficients of the non-linear function. Once the coefficients are obtained, an inference engine may be used to evaluate the non-linear relationship between the coefficients and factor concentrations within the blood sample. Advantageously, the waveform of the actual sample may be detrended to extract a residual oscillatory component to aid in the determination of initial coefficients for simplifying the curve fit operation. The non-linear equation may additionally be used for providing simulated clotting waveforms for testing clot analysis instruments. A residual oscillatory component may advantageously be extracted from the clotting signal.

Abstract: A method and apparatus are provided for accessing a sealed container, and in particular a sealed container which is at a pressure other than atmospheric and which generally contains blood or other bodily fluid. A piercer and a probe are provided which are mounted to an XYZ positioning mechanism and are controlled such that the piercer passes through a stopper of the container, forming a cut therein through which the probe may subsequently enter the container. A foot mechanism is provided which is held against the stopper or seal for the container during piercer or probe removal for stripping purposes and through which the probe and piercer pass, the size and shape of the foot being such that, for both piercing and probing operations, it is over only a single container. The piercer and probe are operated such that the one not being used is in each instance in a raised position relative to the one being used.

Abstract: A feeder system for sequentially supplying a plurality of cuvettes or other objects to a conveyor track. The system includes a cassette, an escapement, and an actuator. The cassette retains the objects/cuvettes in at least one substantially vertical stack over the conveyor. The escapement is movable between a first position in which the escapement supports the bottom object in the stack, a second middle position in which the escapement supports both the bottom object and the object above it and a third position in which the escapement continues to support the object in said stack above the bottom object and releases the bottom object to be deposited on the conveyor. The actuator moves the escapement between the first, second and third positions. Novel apparatus for use in the system, including a stick for loading cuvettes into a cassette and a cuvette particularly adapted for stacking, are also provided.

Abstract: A precision peristaltic pump is provided which assures that a precisely controlled length of tubing is operated upon by the pump. Recesses are provided on either side of a tube receiving gap for the pump, which recesses have different sizes and/or shapes and fittings are provided on the tubing on either side of a precisely determined length of tubing, which fittings are sized and/or shaped so as to only fit in one of the recesses in only a single orientation. This assures that the orientation of the tubing in the pump gap is always the same. The fittings may be a block which is formed on the tubing itself and of the same material as the tubing or may include a stop of a harder material, such as a hard plastic, mounted to or sandwiching each block. The pump is designed so that if one of the fittings is not fully seated in the corresponding recess, the projecting fitting interacts with a cover or other element of the pump to prevent the pump from being moved to its operative position.

Abstract: Optical encoding of a cuvette or other object is provided by means of multiple facets molded integrally into flanges or other portions of the object, which facets selectively refract light passing therethrough in accordance with a predetermined code. The detector for the coded light includes a separate detector for each code state of the facets, with the detector having a different output when no facets are between a light source and the detectors. The facets are preferably bevels, which are selectively angled in accordance with the code.

Abstract: A method and apparatus are provided for use with a centrifuge to analyze reactants. The apparatus includes at least one cuvette having at least one chamber. The chamber has a radially outward wall which provides a base upon which reactants can be pelleted when the device is rotated about a centrifugal axis. Each cuvette includes one or more openings for introducing fluids to the cuvette and includes a channel positioned adjacent to the radially outward wall for removing fluids from the chamber. Pressure is applied to the chamber to force fluids therefrom, through the channel. A hold down device is also provided through which fluid and/or pressure may be passed with respect to the cuvette. The invention also provides a method for determining the existence and degree of agglutination of reactants in a first fluid suspension and contained in a single reaction vessel using a photodetector.

Abstract: A capacative probe is provided which has reduced effective stray capacitance and is thus able to accurately detect probe contact with a conducting fluid with small fluid volumes. Effective stray capacitance is reduced by dividing stray capacitance sources into two or more sources, by reducing the capacitance value of each of the divided stray capacitance sources to a value which is substantially less than the capacitance difference which occurs as a result of probe contact with the fluid and by connecting at least selected ones of the divided stray capacitance sources in series to further reduce effective stray capacitance.

Abstract: A fluid cup is provided for use with a cup support having a cup-receiving receptacle and a drain. The cup is adapted for use with a pipette probe which may introduce contaminants into the fluid, for example a dilutant fluid, in the cup. The cup has a lower cup portion and a cap, with a notch or other overflow element being provided near the top of the lower cup portion. Diluent fluid is introduced near the bottom of the lower cup portion after each probe entry, creating a fluid flow pattern which flushes any contaminant from the cup through the notch without requiring the use of a large fluid volume.

Abstract: A cuvette suitable for use with photometric blood testing apparatus and the like. The cuvette includes a receptacle having flanges on either side having locating holes therein. The flanges are flexible to enhance the positioning of the cuvette. Single and dual cuvette embodiments are described.The invention additionally includes means for encoding a cuvette for optical detection thereof by means of multiple facets which reflect light passing therethrough molded integrally in the flanges.

Abstract: This invention provides a method and apparatus for correcting for the hydrostatic dead volume error which may occur in a pipette system and may also include method and apparatus for correcting for a lost fluid volume error. The technique involves determining the height of fluid in the tip for a desired fluid volume, determining the change in the dead volume resulting from having fluid of such height in the tip and determining the piston displacement required to achieve a volume equal to the sum of the desired volume and the determined change in dead volume, this determined displacement being the piston movement required to achieve the desired fluid volume. The height is determined from the volume multiplied by values which are constant for a given tip size and geometry. The change in dead volume varies as a function of the desired fluid height times a constant for a given fluid, pipette system and tip.

Abstract: A pipette system in which a pipette is controlled by a pre-programmed control unit to perform any selected one of a number of liquid dispensing functions, such as pipetting single volumes of liquid, multiple dispensings from an aspirated volume of liquid, dilutions, and titrations. The control unit also permits new programs for liquid dispensing functions to be written and stored therein.

Abstract: A coagulation instrument for determining clotting times of plasma as an indication of various blood factors. The instrument is adapted to use three or more different reagents which are added selectively to plasma samples in accordance with a code on a cuvette in which the plasma sample is carried through the instrument. Different clotting time tests may be performed sequentially in random order as determined by the coded cuvettes.

Abstract: A plurality of cuvettes joined together by breakable links between each cuvette for use in testing blood for its ABO classification and the presence of a typical antibodies, and for crossmatching blood for compatibility, together with label means for indicating the reagents used in each cuvette and the identity of the person whose blood is being tested. The cuvettes may be adapted to accept a closure means which permits the cuvettes to be pre-packaged with reagents required to carry out blood tests. The cuvettes have a hydrophilic polymer coating thereon that is non-destructive of red blood cells.

Abstract: In a photometric coagulation instrument a synthetic clot signal is generated so that the operation of the instrument can be checked without the need to measure the actual clotting time of a control plasma sample.

Abstract: A dual receptacle cuvette adapted for use in a plasma coagulation testing apparatus which cuvette is coded to enable the apparatus to determine the particular test procedure to be performed on the plasma sample in the cuvette receptacles.

Abstract: A reagent delivery system having a reagent reservoir adapted to permit mechanical stirring of the reagent therein and removal of the reagent from the bottom of the reservoir, and a compact heat exchange unit through which the reagent flows to facilitate rapid heating of the reagent immediately prior to its use in a testing apparatus.

Abstract: A pipette calibration kit containing a plurality of solutions, each of a predetermined concentration, which are used for plotting a calibration curve, and at least one reagent of a predetermined concentration which is used to replace an identical quantity of diluent in a predetermined volume of the diluent. The concentration of the reagent-diluent mixture is measured and the quantity of the reagent substituted for diluent in the reagent-diluent mixture, i.e., the volume of the pipette used to add the reagent to the diluent, is determined from the calibration curve.

Abstract: An improved disposable pipette tip adapted to nest one within another and having a steeply tapered side wall to minimize the length to volume ratio of the tip. An improved self standing tray for the tip also is disclosed as is a new package for pipette tips.

Abstract: A blood bank microscope in which cell/serum-reagent reactions can be viewed, from below, directly in the cuvettes in which the reactions take place and in which the cuvettes can be rocked to cause the contents thereof to flow back and forth within the viewer's field of observation.

Abstract: A manual pipette adapted to use disposable plastic tips into which a liquid is drawn and from which it is dispensed is provided with means for dislodging the tip from the pipette after use. The disposable tip which is normally frictionally held at the distal end of the pipette is pushed off the pipette by a sleeve member that is slideably mounted on the barrel of the pipette.