Abstract:
Method and system for obtaining a liquid sample from a particulate matter-containing liquid in, e.g., a specimen container. A receptacle is used that has an inlet and a chamber for collecting the liquid sample. A discharge passage accommodates upward flow of liquid from the container. The discharge passage preferably has an upper discharge port, and at least one intake submerged in the liquid in the container. A flow-metering passage prevents particulate matter above a predetermined size from passing into the receptacle chamber. Liquid transfer commences after the receptacle inlet is placed in liquid-tight communication with the discharge port. Operation of mechanized system also is disclosed, as well as an arrangement and method for handling multiple receptacles at a liquid transfer station.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional application No. 60/626,441, filed Nov. 10, 2004. This application also is a continuation-in-part of international application No. PCT/US04/37249, filed Nov. 9, 2004; and is a continuation-in-part of U.S. application Ser. No. 10/274,381, filed Oct. 21, 2002 (US 2003/0087443 A1). These three applications are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention is directed to the collection and processing of liquid specimens for subsequent testing or analysis, e.g., biological fluid specimens, such as used in cytology or molecular diagnostic protocols, or non-biological specimens, such as drinking water containing impurities. 
       BACKGROUND 
       [0003]    US 2003/0087443 A1 discloses an example of an automated (computer-controlled) apparatus for handling specimen vials. The apparatus may be referred to as an “LBP” processor (for liquid-based preparation), and can be integrated into a complete automated laboratory system. 
         [0004]      FIG. 1  (a schematic top plan view) shows the overall arrangement of the automated processor disclosed in US 2003/0087443 A1. The LBP processor transports multiple specimen vials sequentially through various processing stations and produces fixed specimens on slides, each slide being bar-coded and linked through a data management system (DMS) to the vial and the patient from which it came. In the preferred arrangement, each vial has a special internal processing assembly detachably coupled to its cover, and is transported through the LBP processor on a computer-controlled transport (conveyor)  240 , in its own receptacle  246 . (In the example shown the conveyor has thirty receptacles.) The containers and the receptacles are keyed so that the containers proceed along the processing path in the proper orientation, and cannot rotate independently of their respective receptacles. 
         [0005]    The containers first pass a bar code reader  230  (at a data acquisition station), where the vial bar code is read, and then proceed stepwise through the following processing stations of the LBP processor: an uncapping station  400  including a cap disposal operation; a preprocessing station  500 ; a filter loading station  600 ; a specimen acquisition and filter disposal station  700 ; and a re-capping station  800 . These six stations are structured for parallel processing, meaning that all of these stations can operate simultaneously on different specimens in their respective containers, and independently of the other. The conveyor will not advance until all of these operating stations have completed their respective tasks. 
         [0006]    The preprocessing station is the location at which preprocessing operations, such as specimen dispersal within its container, are performed prior to the container and its specimen moving on for further handling. The preprocessing station typically performs a dispersal operation. In the preferred embodiment, the dispersal operation is performed by a mechanical mixer (stirrer), which rotates at a fixed speed and for a fixed duration within the specimen container. The mixer serves to disperse large particulates and microscopic particulates, such as human cells, within the liquid-based specimen by homogenizing the specimen. Alternatively, the specimen may contain subcellular sized objects such as molecules in crystalline or other conformational forms. In that case, a chemical agent may be introduced to the specimen at the preprocessing station to, for example, dissolve certain crystalline structures and allow the molecules to be dispersed throughout the liquid-based specimen through chemical diffusion processes without the need for mechanical agitation. Such a chemical preprocessing station introduces its dispersing agent through the preprocessing head. 
         [0007]    There is also an integrated system  900  that includes additional bar code readers, slide cassettes, handling mechanisms for slide cassettes and individual slides, and a slide presentation station  702  at which the specimen acquisition station transfers a representative sample from a specimen to a fresh microscope slide. An optional auto loading mechanism  300  automatically loads and unloads specimen vials onto and from the transport mechanism. All stations and mechanisms are computer-controlled. 
         [0008]    In the preferred embodiment of this LBP processor, the vial uncapping station  400  has a rotary gripper that unscrews the cover from the vial, and discards it into a biosafety disposable waste handling bag. Before discarding the cover, however, the uncapping head presses on the center of the cover as described above to detach the internal processing assembly (stirrer) from the cover. The preprocessing (mixing) station  500  has an expanding collet that grips the processing assembly, lifts it slightly and moves (e.g., spins) it in accordance with a specimen-specific stirring protocol (speed and duration). The filter loading station  600  dispenses a specimen-specific filter type into a particulate matter separation chamber (manifold) at the top of the processing assembly. The specimen acquisition station  700  has a suction head that seals to the filter at the top of the processing assembly and first moves the processing assembly slowly to re-suspend particulate matter in the liquid-based specimen. Then the suction head draws a vacuum on the filter to aspirate the liquid-based specimen from the vial and past the filter, leaving a thin layer of cells on the bottom surface of the filter. Thereafter the thin layer specimen is transferred to a fresh slide, and the container moves to the re-capping station, where a foil-type seal is applied. 
         [0009]    The LBP processor shown in  FIG. 1  also is equipped with a liquid sampling draw station  100 , which is adapted to place a specially designed liquid collection receptacle into engagement with the processing assembly (stirrer) present in any of the specimen containers processed by the LBP processor. The receptacle is in the form of a molded plastic cuvette, and has a thermoplastic elastomer one-way valve on one end that mates with and seals against the upper end of the processing assembly. The valve admits liquid into the cuvette when the cuvette is placed under vacuum to draw liquid from the specimen container up through the processing assembly. The valve is otherwise sealed to prevent the escape of liquid from the cuvette. A syringe or a cannula can be used to withdraw liquid from the cuvette for testing. Preferably the cuvette is bar-coded so that it can be linked to the specimen vial and the patient identifying data through the DMS. 
         [0010]    As illustrated in  FIG. 1 , the liquid sampling draw station  100  is located just after (downstream of) the mixing station  500  of the LBP processor. However, the liquid sampling draw station instead could be located downstream of the specimen acquisition station  700 . Actuation of the liquid sampling draw station  100  preferably is governed by the particular processing protocol for each specimen. Accordingly, there may be specimen containers from which no liquid sample is drawn, in which case the liquid sampling draw station will remain idle while such a container dwells there. It is also possible for the liquid sampling draw station to draw a variable liquid volume, again dependent on the particular processing protocol for each specimen. To accomplish that, a plurality of vertically spaced liquid level sensors would monitor the changing level of liquid in the receptacle, and liquid draw would be terminated when the specified liquid volume is acquired. 
       SUMMARY DISCLOSURE OF THE INVENTION 
       [0011]    The invention disclosed in the present application concerns liquid sample collection in general. It also concerns a liquid sampling draw station that may be used in an LBP processor, and the liquid collection receptacles (cuvettes) that may be employed at that station. The invention further concerns operation of an LBP processor, which may be controlled with respect to an individual vial, depending on protocol, so as to draw a liquid sample from the vial at the liquid sampling draw station, and/or to draw liquid at the specimen acquisition station to make a slide-mounted sample, in either order. 
         [0012]    A first aspect of the invention concerns methods and systems for obtaining a liquid sample containing size-restricted particulate matter from a particulate matter-containing liquid in a container. A receptacle is used that has an inlet and a chamber for collecting the liquid sample. A discharge passage accommodates upward flow of liquid from the container. The discharge passage preferably has an upper discharge port, and at least one intake submerged in the liquid in the container. A flow-metering passage prevents particulate matter above a predetermined size from passing into the receptacle chamber. The receptacle inlet is placed in liquid-fight communication with the discharge port, and particulate matter-containing liquid is caused to flow from the container upwardly through the discharge passage, through the receptacle inlet and into the receptacle chamber. The flowing liquid also passes through the flow-metering passage so that the liquid sample collected in the receptacle contains only size-restricted particulate matter. 
         [0013]    The discharge passage, the discharge port and the intake may be in a discharge element that is associated with the container, i.e., is in, is insertable into, or is part of the container. For example, the discharge element may be the tubular portion of a processing assembly that is already in the container, or a tube that is inserted into the container just prior to sample collection, or part of the container wall. The flow-metering passage may be associated with the discharge passage or the receptacle. For example, the intake may act as the flow-metering passage; or the flow-metering passage may be a filter in the receptacle located between the inlet and the chamber for collecting the liquid sample. 
         [0014]    Another aspect of the invention concerns a method for optionally obtaining a liquid sample and/or a particulate matter sample from a particulate matter-containing liquid specimen in a container. The method uses an apparatus comprising a liquid sampling station for collecting a liquid sample in a receptacle having a resilient tip with an inlet, and a specimen acquisition station having an aspiration head for collecting a sample layer of particulate matter separated from the liquid on a surface of a filter. The container has therein a processing assembly comprising an upper separation chamber adapted to receive a filter and a tube extending downwardly from the separation chamber into the specimen liquid in the container. The tube has a vent hole above the level of specimen liquid in the container. The method involves optionally performing one or both of the following series of steps (a) and/or (b) in either order: 
         [0015]    (a) inserting the resilient tip of the receptacle into the upper end of the tube to form a seal with the upper end of the tube and seal off the vent hole, and applying a vacuum to the receptacle to withdraw liquid from the container through the inlet and into the receptacle; 
         [0016]    (b) placing a filter in the separation chamber, sealing the aspiration head to the upper portion of the separation chamber, and applying a vacuum to aspirate liquid from the container through the tube and aspirate air into the tube through the vent hole, whereby particulate matter is separated from the aspirated liquid, and a sample layer of particulate matter is formed on a surface of the filter. 
         [0017]    A further aspect of the invention concerns a method and apparatus for handling receptacles at a liquid sampling station. Each receptacle has a bottom inlet adapted to dock with an upwardly facing port through which liquid can flow. At least one carrier is used to removably hold a plurality of receptacles. The carrier is advanced along a path that extends toward and away from a liquid transfer location. One receptacle at a time is removed from the carrier. The removed receptacle is moved so as to dock the inlet of the receptacle with the port. Then the receptacle is moved so as to undock the inlet from the port, and the receptacle is returned to the carrier. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0018]    Embodiments that incorporate the best mode for carrying out the invention are described in detail below, purely by way of example, with reference to the accompanying drawing, in which: 
           [0019]      FIG. 1  is a schematic top plan view of an automated specimen processing apparatus with which the present invention can be used; 
           [0020]      FIG. 2  is an elevational view of a cuvette according to the invention; 
           [0021]      FIG. 3  is a longitudinal sectional view of the cuvette of  FIG. 2 ; 
           [0022]      FIG. 4  is a vertical sectional view through a specimen container and the cuvette of  FIG. 2  engaged with the processing assembly; 
           [0023]      FIG. 5  is a detail view of a portion of the container, processing assembly and cuvette shown in  FIG. 4 ; 
           [0024]      FIG. 6  is a perspective view of the cuvette engaged with the processing assembly of a specimen container (shown cradled in a receptacle of the LBP processor) and showing a portion of a cuvette docking mechanism according to the invention; 
           [0025]      FIG. 7  is a perspective view of the processing assembly; 
           [0026]      FIG. 8  is a bottom plan view of the processing assembly; 
           [0027]      FIG. 9  is an exploded vertical sectional view of the processing assembly and a filter assembly adapted for use in the processing assembly; 
           [0028]      FIG. 10  is a top plan view of the center portion of the bottom wall of the container according to another embodiment of the invention; 
           [0029]      FIG. 11  is an elevational view of the lower portion of the processing assembly according to another embodiment of the invention; 
           [0030]      FIG. 12  is a vertical sectional view of the lower portion of the processing assembly in a container taken along line  12 - 12  in  FIG. 8 ; 
           [0031]      FIG. 13  is a perspective view of the liquid sampling draw station according to the invention; 
           [0032]      FIG. 14  is a perspective view of an LBP processor generally of the type shown in  FIG. 1 , and incorporating the liquid sampling draw station of  FIG. 13 ; 
           [0033]      FIG. 15  is a front elevational view of the LBP processor of  FIG. 14 ; 
           [0034]      FIG. 16  is a close-up perspective view of a portion of the LBP processor of  FIG. 14 ; 
           [0035]      FIG. 17  is a perspective view of the cuvette docking mechanism; 
           [0036]      FIG. 18  is a top plan view of the cuvette docking mechanism of  FIG. 17 ; 
           [0037]      FIG. 19  is a perspective view of a clip according to the invention holding ten cuvettes for transport to and from the docking mechanism; 
           [0038]      FIG. 20  is a perspective view of a transport mechanism according to the invention for transporting cuvettes to and from the docking mechanism; 
           [0039]      FIG. 21  is a perspective view of the feeder tray for housing fresh (empty) cuvettes; and 
           [0040]      FIG. 22  is a perspective view of the receiver tray for housing used (filled) cuvettes. 
       
    
    
       [0041]    It is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components of the preferred embodiments described below and illustrated in the drawing figures. Various modifications will be apparent to those skilled in the art without departing from the scope of the invention. Further, while the preferred embodiment is disclosed as primarily useful in the automated collection and processing biological fluids for cytology examination and/or analysis, it will be appreciated that the invention has manual or automated application in any field in which liquid specimens are sampled. 
       DETAILED DESCRIPTION 
     Cuvette Docking 
       [0042]    Referring to  FIGS. 2-6 , a cuvette  10  according to the invention has a slender cylindrical body  12  with a tapered lower end  14 , an open upper end  16 , and an upper collar  17 . The cuvette body  12  is molded of plastic, preferably clear or translucent polyethylene, and preferably is sized to hold up to about 5 ml. of specimen liquid. A unique machine-readable bar code  18  is carried by the body  12 , preferably applied by laser etching. 
         [0043]    A thermoplastic elastomer stopper  20  permanently seals the upper end  16 . Stopper  20  is molded with an integral membrane  22 , which can be pierced by a cannula for both specimen aspiration and for subsequent sample withdrawal for testing or analysis. Membrane  22  is self-sealing so that it will not leak after the cannula is withdrawn. 
         [0044]    The lower end  14  of the cuvette preferably is shaped to mate with the upper end of the processing assembly  40  of a specimen vial, and is fitted with a tapered, one-way valve  24  molded of a thermoplastic elastomer. The resilient nature of the valve material normally keeps the small flow passage  26  therein squeezed tightly shut without the potential for leakage. The valve has an exposed, tapered surface  28 , the purpose of which is to act as a gasket when it is coupled to the suction tube  43  of the processing assembly (stirrer)  40  in the specimen container  30  (which is in a receptacle  246  on the conveyor of the LBP processor). The exposed surface  28  of the valve enters and positively seals against the upper end (discharge port) of the stirrer suction tube  43 . It also seals off a vent hole  44  near the upper end of the suction tube so that the vacuum applied to the cuvette will work effectively to draw specimen liquid up through the lumen  43   a  of the suction tube, and so that air will not be entrained in the liquid sample. 
       Sample Metering 
       [0045]    A small percentage of patient specimens, as may be found in gynecological Pap test and other specimen types, contain large clusters of cells, artifacts, and/or cellular or noncellular debris. Some of these large objects, if collected and deposited with a slide-mounted cellular sample, can obscure the visualization of diagnostic cells and, consequently, result in a less accurate interpretation or diagnosis of the slide sample. Since most of these features are not of diagnostic relevance, their elimination from the sample is, in general, desirable. It is also desirable to eliminate such large objects from liquid specimens collected in cuvettes. To achieve this result, close control of the bottom inlets to the suction tube  43  is maintained, as follows. 
         [0046]    Referring to  FIGS. 7 ,  8 ,  9  and  12 , the bottom end of suction tube  43  is provided with a plurality of standoffs in the form of peripherally spaced feet  52  that contact the bottom wall  23  of the container to define a plurality of peripherally spaced inlets  54  to the tube. This interface effectively forms a plurality of metering valves. Proper sizing and spacing of the feet  52  (and therefore the inlets  54 ) prevents large objects from entering the suction tube  43 , while allowing the passage of smaller objects that may be diagnostically useful. The minimum dimension of the cross-section of any inlet (as well as the minimum height of any foot) for cytology specimens preferably is in the range of about 0.004 in. to about 0.020 in. For gynecological specimens, the minimum height of any foot (or any inlet) preferably is about 0.010 in. For non-cytology specimens the preferred minimum inlet size will depend on the size distribution of the particulates in the specimen. 
         [0047]    While the inlets  54  have a thin (low) passage section as illustrated and a small metering area, clogging is not an issue due to the relatively wide dimension. Having a plurality of inlets ensures that liquid flow will not be interrupted because, should one inlet become clogged, others will accommodate the flow. Further, because the bottom end of the tube is flared outwardly at  56 , a net larger inlet area is formed to help the liquid bypass any clogged inlets. Eight feet (defining eight inlets) are shown in the figures, but a different number of feet may be used—two at a minimum. Although squared-off feet are shown, the feet could have rounded inside corners, and/or could have rounded outside corners. Regardless of the number or shape of the feet, minimum inlet size preferably should fall within the above cross-section range of about 0.004 in. to about 0.020 in for cytology specimens. 
         [0048]    Substantial contact of the tube with the bottom wall  23  of the container is important. To that end, aspiration tube  43  is dimensioned such that, when the aspiration head engages the stirrer with a downward force, the feet  52  will firmly contact bottom wall  23 , which can flex downwardly if necessary depending on manufacturing tolerances. 
         [0049]    The objective is to draw specimen liquid from the lowest part of the container, where particulates may settle even after vigorous mixing, while metering to prevent the passage of particulates larger than a specified threshold. Other inlet-defining structural arrangements at the interface between the bottom end of suction tube  43  and bottom wall  23  may be used to accomplish this. For example, the bottom end of tube  43  may be smooth (i.e., have no feet), while the bottom wall  23  may have standoffs against which the end of tube  43  rests.  FIG. 10  shows an example of this arrangement, in which bottom wall  123  is provided with integrally molded, upstanding, radial ribs  152 . The annular bottom end face  143  of the suction tube is shown in dashed lines superposed above the ribs  152 . Here, eight ribs  152  are shown radiating from a central boss  124 , the ribs and the end of the suction tube defining eight inlets  154 . Ribs or standoffs of different shape (e.g., curved), number and/or configuration could also be used as long as they cooperate with the bottom end of the suction tube to define a plurality of inlets of proper size. 
         [0050]    Alternatively, standoffs could be provided on both the bottom end of the suction tube and the bottom of the container, the standoffs cooperating to define a plurality of inlets of the required size. However, inasmuch as such an arrangement could interfere with rotation of the processing assembly (stirrer) during mixing, it is better left to embodiments in which the processing assembly does not rotate, with mixing effected by some other instrumentality (see below). 
         [0051]    In lieu of structures that define inlets between the bottom end of the suction tube and bottom wall  23  of the container, the suction tube may have a plurality of peripherally spaced orifices located immediately adjacent the bottom end of the tube.  FIG. 11  shows an example of these orifices as elongated openings  254  in suction tube  243 ; other shapes (not shown) may also be used. Regardless of the inlet arrangement, minimum inlet size preferably should fall within the above cross-section range of about 0.004 in. to about 0.020 in. for cytology specimens. 
         [0052]    While a rotatable processing assembly  40  with mixing vanes  45  has been disclosed, it will be appreciated that specimen mixing could be accomplished without rotation of the processing assembly by using other known types of agitating arrangements. For example, vibratory energy could be applied to the upper portion of a processing assembly having mixing elements that are suitably designed to impart such energy efficiently to the specimen liquid. As another example, vibratory energy could be imparted to the container  20  when appropriately supported, and the processing assembly may be devoid of mixing elements or have mixing elements that enhance the vibrational mixing. As yet another example, ferromagnetic beads could be incorporated in the vial (e.g., at the factory), and these beads would be caused to move throughout the specimen under the influence of a moving magnetic field imposed, e.g., by a rotating magnet located beneath the vial. Such beads would remain in the vial during sampling because the metering feature of the invention, described above, would prevent the beads from becoming entrained in the liquid sample as it is removed from the container. In such an embodiment, the processing assembly could have no mixing elements, or small mixing elements that cooperate with the beads to enhance mixing. Regardless of the type of mixing arrangement used, the processing assembly, in order to be useful for making slide-mounted samples, would have an upper portion with a manifold  46  for receiving a filter assembly F (see  FIG. 9 ), and a suction tube  43  that preferably meters the sample flow of specimen liquid from the bottom of the container. 
         [0053]    Additional metering for liquid samples optionally may be provided by at least one flow-metering passage in the cuvette itself. This may be needed if, for example, the flow metering afforded at the bottom of the processing assembly is not restrictive enough for liquid sampling purposes. The flow-metering passage can take any suitable form. As an example, a filter  27  of any suitable type (shown in dashed lines in  FIG. 5 ) may be located just inside the inlet flow passage  26  to form a barrier to incoming particulates that exceed the size of the filter pores, keeping such particulates from entering the collection chamber within the cuvette. 
         [0054]    In terms of liquid sampling as a separate operation, it should be noted that the invention in its broadest aspects does not require specimen premixing, or any type of specimen preprocessing. Nor does it require the use of specimen vials that come prepackaged with the special internal processing assembly (stirrer)  40  shown in  FIG. 4 . Accordingly, it is possible to carry out the liquid sampling operation of the invention by making use of any arrangement that provides a discharge passage through which liquid can flow upwardly from the specimen container to a receptacle (cuvette). 
         [0055]    For example, the discharge passage can be the lumen of a tube that is placed in the specimen container at or shortly before the time the liquid sampling operation is to take place. Such a tube optionally may be provided with stabilizing/positioning elements; and it may be provided with any type of flow-metering arrangement, such as an internal restriction or any of the arrangements described above; or with no flow-metering arrangement at all. In either case, the cuvette may be provided with its own flow-metering arrangement, as described above, as either the sole or a supplemental metering arrangement. As another example, the discharge passage could be associated with the container wall. It could be a separate tubular element supported by the container wall, or an integral part of the container itself, such as hollow tubular boss or other tubular structure formed as part of the container wall, with or without a flow-metering arrangement (which in any case may be provided in the cuvette). 
       Cuvette Handling 
       [0056]    The liquid sampling draw station  100  is shown in  FIG. 13 , separated from the rest of the LBP processor. Draw station  100  is mounted in a common housing and has the following main components: (1) a feeder tray  102  for housing fresh (empty) cuvettes (tray  102  may include a spring-loaded pusher plate  103  for urging cuvettes toward the feeding end of the tray); (2) a receiver tray  104  for housing used (filled) cuvettes; (3) a transport mechanism  110  for transporting cuvettes from feeder tray  102 , across the path of the conveyor of the LBP processor, to receiver tray  104 ; and (4) a docking mechanism  120  for removing one cuvette at a time from the transport path, docking it with the processing assembly of a specimen vial, and returning it to the transport path.  FIGS. 14-16  show the liquid sampling draw station  100  installed in the LBP processor. 
         [0057]    Referring to  FIGS. 19 and 21 , cuvettes  10  are loaded into feeder tray  102  in groups of ten carried by clips  50 . Each clip has ten sleeves  52 , one for each cuvette, and each sleeve has a window  54  through which the cuvette bar code can be read by a bar code reader (not shown). Each cuvette is retained in a sleeve  52  by means of its collar  17 , which rests on the upper end of the sleeve, and can be lifted out of the clip by the docking mechanism. Clips are fed out of feeder tray  102  by a clip magazine feeder (not shown), which comprises a walking-beam type feed mechanism actuated by air cylinders. 
         [0058]    Portions of the transport mechanism  110  are shown in  FIGS. 17 and 20 . Upper and lower rails  112 ,  114  guide cuvette clips  50  from the feeder tray  102  to the receiver tray  104 . A notched advancing plate  116  is mounted for lateral movement (parallel to rails  112 ,  114 ), and for oscillating movement toward and away from the rails, by means of an escapement mechanism (not shown). Advancing plate  116  thus engages a clip  50  to move it stepwise (i.e., one cuvette at a time) as instructed by the controller of the LBP processor. Clips of cuvettes are processed in a seamless operation as they are presented by the clip magazine feeder. 
         [0059]    Portions of the docking mechanism  120  are shown in  FIGS. 17 ,  18  and  20 . Cuvettes are shuttled from the clip position to the docking (aspiration) position and back to the clip position by the action of a Theta- and Z-axis robotic arm  122 . Movement along these two axes is effected by step motors (not shown) through a commercial screw rail  126  as the base mechanism. Arm  122  has a gripper  124  adapted to releasably grip the upper end of a cuvette beneath collar  17 , lift it out of the clip, move it to the docking position, and then move it back to the clip after sample acquisition. A retractable, pneumatically-actuated cannula  128  is mounted to arm  122  and is connected to a vacuum line  130 . 
         [0060]    In operation, the robotic arm  122  will move to the clip position where the gripper  124  engages and locks on the cuvette to be processed. Cannula  128  will then pierce the stopper membrane  22  to a fixed distance. At this point, the Z axis motor will extract the cuvette from the clip  50  and transfer it to the aspiration position, where it will come into contact with the processing assembly (stirrer)  40  in the specimen vial. A seal will be formed between the stirrer suction tube  43  and the cuvette&#39;s one-way valve  24 . Liquid will then be aspirated into the cuvette by vacuum forces. Aspiration will continue until a liquid-level sensor indicates a programmed acceptance level. At that point, aspiration will be suspended and the cuvette will be returned to the clip. 
         [0061]    The capacity of feeder tray  102  can be tailored to suit processing needs. Additional clips of cuvettes can be added to the feeder tray  102  at any time in the processing operation. Clips are processed on a first-in, first-out sequence. Seamless integration with the LBP processor ensures efficient and reliable operation. 
       INDUSTRIAL APPLICABILITY 
       [0062]    The invention thus provides an efficient, convenient, safe and effective system and method for collecting, handling and processing biological specimens and other specimens of particulate matter-containing liquid. Although not restricted to automated use, it is ideally suited for use in automated equipment that provides consistently reliable processing tailored to sample-specific needs. Such equipment may be part of a complete diagnostic laboratory system.