Abstract: A separation procedure for separating a selected desired or undesired population from a biological sample utilizing relatively heavy, dense particles and gravity sedimentation. The particles have one or more reactants bound thereto which are specific to and will bind with the selected population. The particles preferably are mixed with the sample by repeatedly causing the particles to settle through a substantial portion of the sample to bind to the selected population. The particles with the bound selected population then are allowed to preferentially settle in the sample and the supernatant including an enriched population is separated from the particles with the selected population bound thereto. The enriched populations in the biological sample supernatant can be further enriched by multiple removal steps.

Abstract: A method for performing screening of one or more cell groups of interest obscured by a cell population such as one or more subsets of interest of a WBC population utilizing at least one light sensing parameter. The cell group of interest is enumerated by utilizing microspheres having monoclonal antibodies bound thereto to modify the sensed characteristics of specified cells to differentiate the cell group of interest from the obscuring cell population.

Abstract: A method and apparatus for performing screening of obscured or partially obscured cells to enumerate one or more cell population subsets. For example, a whole blood sample or portion thereof is screened to provide the desired analysis of one or more white blood cell population subsets in the sample. A white blood cell population including the obscured subset of interest is first counted, along with a standard population. The standard population can be one of the total number of white blood cell populations, a second white blood cell population which does not obscure the shifted or non-shifted sensed characteristic of the subset of interest, an artificial population formed by microspheres which also do not obscure the shifted or non-shifted sensed characteristic of the subset of interest or a white blood cell population into which the sensed characteristic of the subset will be wholly or partially shifted.

Abstract: A method and transfer device for transferring fluids between closed vials. The transfer device includes a cylinder having a pair of opposing open tubes or tubular portions into which a pair of vials can be inserted to transfer fluid therebetween. The tubes are separated by a wall through which extends a fluid transfer needle and a vent needle which first is inserted into a first vial to vent the first vial into a vent chamber or reservoir formed in the transfer device before the transfer needle is inserted into the first vial. The first vial, stopper first, is inserted into first tube until seated onto an exposed end of the transfer needle. A second vial, stopper first, then is inserted into the second tube until seated onto the opposite exposed end of the transfer needle. A pressure differential between the closed vials preferably can be utilized to transfer a desired fluid portion between the vials.

Abstract: A separation procedure for separating a selected desired or undesired population from a biological sample utilizing relatively heavy, dense particles and gravity sedimentation. The particles have one or more reactants bound thereto which are specific to and will bind with the selected population. The particles preferably are mixed with the sample by repeatedly causing the particles to settle through a substantial portion of the sample to bind to the selected population. The particles with the bound selected population then are allowed to preferentially settle in the sample and the supernatant including the non-selected population is separated from the particles with the selected population bound thereto. The particles can be heated for sterilization and endotoxin removal.

Abstract: A method and apparatus for accelerating at least one definitive biological reaction including increasing the accuracy of determinations made therefrom. The reaction involves selected viable biological cells which are prepared in a small sample volume and rapidly mixed with microspheres having antibody specific at least to specific ones of the cells bound thereto. The microspheres can be magnetic and the bound cells can be magnetically removed to analyze the remaining blood cell populations. The microspheres can be introduced sequentially or simultaneously.

Abstract: A method and apparatus for automatically and rapidly, retrieving, counting and/or analyzing at least one selected white blood cell population and/or subset thereof of a whole blood sample or portion thereof. A volume of a biological sample containing the white blood cells is prepared and at least one reactant specific or preferential at least to some selected biological cells is introduced thereto and rapidly mixed for a short period of time. The opacity and/or volume parameter of the cells can be modified and the mixture is then counted and analyzed in one or more steps to obtain the desired white blood cell population analysis.The biological sample can be a whole blood sample and the reactant can include or be a lyse or a monoclonal antibody bound to microspheres, which will bind to specific ones of the cells or a combination of lyse and microspheres with antibody bound thereto.

Abstract: An optical screening method and apparatus for identifying and counting cells expressing selected characteristics or properties. The cells are combined with one or more different sets of microspheres, each set having a reactant bound thereto which will bind to a specific molecule which can exist on one or more types of the cells. The cells and microspheres are formed in a known volume on a slide and optically viewed to identify and count the type of cells to which the different sets of microspheres do or do not bind. The cell count then is related to the known volume to provide an absolute cell count. A plurality of different sample portions can be utilized with different reactants to obtain a multipart WBC differential/absolute count. The different sets of microspheres are optically differentiated by having different optical characteristics, such as size, shape, color or combinations thereof.

Abstract: A method and apparatus for automatically and rapidly, retrieving counting and/or analyzing at least one selected population of cells or formed bodies, such as a white blood cell population and at least one subset thereof of a whole blood sample or portion thereof. A volume of a biological medium containing the white blood cells is prepared and at least one reactant specific or preferential at least to some selected biological cells is introduced thereto and rapidly mixed for a short period of time. A multipart blood cell analysis is obtained with a single sensing parameter by depleting at least one WBC subset population. The percentage of a desired WBC population subset or the overlapping of WBC subset populations also can be obtained by subtracting one or more obscuring WBC subset populations.

Abstract: A method and apparatus for accelerating at least one definitive biological reaction including increasing the accuracy of determinations made therefrom. The reaction involves selected viable biological cells which are prepared in a small sample volume and rapidly mixed with microspheres having antibody specific at least to specific ones of the cells bound thereto. The microspheres can be magnetic and the bound cells can be magnetically removed to analyze the remaining blood cell populations. The microspheres can be introduced sequentially or simultaneously.

Abstract: A method and apparatus for automatically and rapidly, retrieving, counting and/or analyzing at least one selected population of cells or formed bodies, such as a white blood cell population and at least one subset thereof of a whole blood sample or portion thereof. A volume of a biological medium containing the white blood cells is prepared and at least one reactant specific or preferential at least to some selected biological cells is introduced thereto and rapidly mixed for a short period of time. The opacity and/or volume parameter of the cells can be modified and the mixture is then counted and analyzed in one or more steps to obtain the desired white blood cell population and subset analysis. The biological sample can be a whole blood sample and the reactant can include or be a lyse or a monoclonal antibody bound to microspheres, which will bind to specific ones of the cells or a combination of lyse and microspheres with antibody bound thereto.

Abstract: A method and apparatus for automatically and rapidly, retrieving, counting and/or analyzing at least one selected white blood cell population and/or subset thereof of a whole blood sample or portion thereof. A volume of a biological sample containing the white blood cells is prepared and at least one reactant specific or preferential at least to some selected biological cells is introduced thereto and rapidly mixed for a short period of time. The opacity and/or volume parameter of the cells can be modified and the mixture is then counted and analyzed in one or more steps to obtain the desired white blood cell population analysis.The biological sample can be a whole blood sample and the reactant can include or be a lyse or a monoclonal antibody bound to microspheres, which will bind to specific ones of the cells or a combination of lyse and microspheres with antibody bound thereto.

Abstract: Disclosed is a flow through particle analyzing cell differentiating apparatus for optical and electronic measurements on a stream of particles in which a hydrodynamically focoussed stream is passed into and through a point focussed beam of radiated energy whereby the beam is scattered by the stream to impinge upon light responsive signal operating members disposed adjacent the cell at angular positions relative to the beam axis of from about 10.degree. to 70.degree..

Abstract: A circuit, which is useful to provide data needed to measure the electrical opacity of a particle, for instance a blood cell, passing through a Coulter type transducer, includes a current source for providing a conventional d.c. current through the sensing aperture of the transducer, as well as an oscillator for providing a high frequency current through the aperture. The oscillator includes an active device and a resonant circuit, and the aperture is coupled in parallel with the resonant circuit of the oscillator. The oscillator can be any type of oscillator, such as a Hartley oscillator. As a particle passes through the aperture, the resistance of the aperture increases, which in turn, increases the Q of the oscillator circuit, whereby the oscillator output signal is amplitude modulated in accordance with the increased Q. This amplitude modulated signal can be detected to provide a value based on the high frequency reactance of the particle being detected. The change in d.c.

Abstract: A debris detector for a particle counter, such as a blood cell counter, of the COULTER (R) type. When a particle, or transient debris, passes through the sensing orifice of the particle detector, a voltage pulse occurs; whereas, when debris lodges in or against the orifice of the particle detector, a d.c. voltage shift occurs. The voltage at the orifice is capacitively coupled to an amplifier and the output of the amplifier is integrated. The capacitor coupling the orifice voltage to the amplifier causes an undershoot voltage at the trailing edge of each particle or transient debris pulse, such that a zero average voltage is applied to and, hence, from the amplifier for each voltage pulse. The integrated voltage is applied to a voltage comparator to provide an output signal therefrom whenever the integrated voltage exceeds a reference voltage. The comparator output signal is provided to a delay circuit having a delay related to the time required for a particle to pass through the COULTER detector orifice.

Abstract: A plurality of sealed blood sample tubes are housed in a rack and a plurality of these racks are vertically stacked, with the sample tubes lying horizontally. The racks are successively deposited onto a horizontal conveyor belt which is housed in and moves longitudinally on a table that rocks around its longitudinal axis to mix the samples in a semi-inverting mode as a rack is stepped from the stack to a sample aspiration station and/or thereat. The aspiration station preferably includes a sample segmenting and diluting valve and a sample identification reader. Aspiration is accomplished by pushing a sample tube partially out from the carrier rack and onto a seal piercing tip of the aspiration probe. The tube then is returned to the rack. The other tubes in that rack similarly are aspirated after the rack is stepped to align each tube with the aspiration probe, with table rocking and sampling mixing accompanying each advancing step of the rack.

Abstract: A stackable cassette or rack for supporting a plurality of sealed sample containers having different diameters and/or lengths and transporting the same to a testing station of a hematology analyzer device. The cassette comprises a body having a top and a bottom and a rear portion, and the body includes a base, front and intermediate walls and a biasing means, connected between the front and intermediate walls, both walls longitudinally extend across the base and each wall has a plurality of equidistantly spaced openings therein arranged in a row lengthwise of the cassette which openings extend from the base to the top of the body. Each of the openings in the front wall has an upper edge and the spaced apart holes of both walls are in alignment.

Abstract: A particle analyzer apparatus comprising a flow cell having a flow chamber wherein a flow of liquid suspension, having individual particles entrained therein, proceeds along a predetermined path; a pair of electrodes are disposed on opposed sides of the predetermined path, one of the electrodes having an end with a width parallel to the predetermined path that is less than the length of a given particle, the end of the electrode being positioned in close proximity to the predetermined path; energizing source for providing an electrical field between the pair of electrodes that traverses the predetermined path; and a particle pulse detector for detecting particle pulses caused by the particles passing through the electric field.

Abstract: A level sensor of a fluid transfer mechanism for determining when the bottom tip of a fluid aspirating probe touches or contacts the top surface of a sample fluid. The level sensor senses the contact capacitively by grounding one plate of a capacitor through the sample fluid and fluid aspirating probe. One capacitor plate is formed of an electrode biased against the bottom of a rotatable supply tray and positioned under a sample containing cavity in the tray. The other capacitor plate is formed by the bottom surface of the sample fluid in the supply cavity, and the dielectric of the capacitor is formed of the supply tray material. An AC signal is applied to the electrode and the probe is grounded. The change in voltage occurring in the AC signal at the electrode when the probe touches the top surface of the sample fluid it is sensed to provide the touch signal.

Abstract: A vertically and horizontally movable arm structure for fluid transfer is provided with a tubular member for linear oscillation of a holder for a fluid probe; the tubular member can additionally form a conduit for lead wire connected to the fluid probe. Sensors for the vertical position of the arm and the conductor leads from the sensors can be separately mounted and routed so that the sensor leads do not kink or interfere with the motion of the arm.