Patent Publication Number: US-8535624-B2

Title: Assay testing diagnostic analyzer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. application Ser. No. 10/614,485, now U.S. Pat. No. 7,458,483, filed Jul. 7, 2003, which is a continuation-in-part of U.S. patent application Ser. No. 09/840,960 filed Apr. 24, 2001, now U.S. Pat. No. 6,588,625, the content of which is expressly incorporated herein by reference thereto. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a sample and reagent handling system for automatically testing samples with a diagnostic module. More particularly, the invention relates to a sample handling system in which sample and reagent carriers are placed in a loading bay and transported by a transporter to a different location depending on the contents of the carriers. The invention also relates to a diagnostic module with a mechanism for locating the carriers in an aspiration position. 
     BACKGROUND OF THE INVENTION 
     In the past, sample handling systems had a single path carrier that would stop at specified locations as desired for testing. In these single path systems, if retesting or preemptive prioritization of a sample were required, the tube would have to travel around the entire module system to be tested or retested. This resulted in either significant delay in testing and retesting or very complex, expensive carrier routing mechanisms. 
     An example of a single path sample handling device is disclosed in U.S. Pat. No. 5,876,670 to Mitsumaki. In Mitsumaki, a sample carrier, holding a plurality of test tubes, is transferred to the analyzer modules by a transporting belt driven by a motor. All the sample carriers on the transporting belt pass through the sampling position for the first analyzer module and preferably must be transferred to a receiving position to reach the sampling position for the second analyzer module. When a sample needs to be retested, then the operator returns the sample carrier to the beginning of the transporting belt. An urgent sample supply portion is provided on one end of the belt near the sample supply portion, allowing urgent sample racks to be processed before the general racks. In Mitsumaki, the sample handling system processes samples sequentially along the transporting belt and does not automatically retest samples. 
     Another example of a prior sample handling system is disclosed in U.S. Pat. No. 5,665,309 to Champseix et al. The Champseix et al. device comprises a holding rack for a plurality of test tubes; a sampling station for sampling the contents of a tube; and a gripping device for withdrawing a tube from a selected position on the rack, bringing the tube to the sampling station and returning the tube back to its selected position. The gripping device moves the individual tubes from a rack to the sampling station. However, the Champseix et al., sample handling device does not disclose a method for automatically retesting samples or processing stat samples. 
     U.S. Pat. No. 5,260,872 to Copeland discloses an automated testing system for the quality testing of production samples, comprising a loading station for receiving a test tube rack containing a plurality of test tubes; a pipetting station; a bead-drop station; and a robotic device having an arm adapted to pick up a test tube rack from the loading station, move the rack to the pipetting station so the fluids can be pipetted into the test tubes; move the rack to the bead-drop station; and return the rack to the loading station in accordance with a computer program. When the Copeland test tube rack is returned to the loading station the tubes may be removed and disposed of and the rack is then loaded with a fresh set of test tubes. The Copeland system does not accommodate for automatic retesting or testing of stat samples. 
     In the past, reagents have been loaded manually in an automated testing system with a diagnostic module. Reagent replacement is often required in the middle of testing due to consumption of the reagent in a kit or expiration of a reagent. In addition, a reagent may be needed when the system needs to run more test types, analytes, in a day than there are reagent positions in the analyzer. The manual loading of the reagents often resulted in interruption of testing in process or at least a loss of throughput. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an assay testing diagnostic analyzer and a handling system thereof. In a preferred embodiment, the handling system includes a loading bay for receiving and holding a plurality of carriers. An identification device is configured for identifying an identifying feature of the carriers or containers to determine the type of contents loaded on each carrier. A transporter is configured for transporting the carriers from the loading bay to a first or second location depending on the determined type of contents on each carrier. A diagnostic process is performed using the contents. The transporter preferably has random access to the plurality of carriers in the loading bay. 
     In this embodiment, the identification device is configured for identifying the contents of the carriers at least as either samples or reagents. The identification device is associated with the transporter such that the transporter can transport the samples to the first location and the reagents to the second location. Although the loading bay can have a sample loading area and a separate reagent loading area, in a more preferred embodiment, however, a single loading area is provided in which the sample in reagent carriers can be positioned in any order. The identification device is preferably configured for identifying the type of contents independently of where in the loading bay the carriers are loaded. Most preferably, the transporter can transport the carriers from and/or to substantially any location in the loading bay and/or the respective first or second location. 
     An advantage of the present handling system is that reagents can be loaded and unloaded as regents are consumed or expired, without interrupting the operation of the automated testing or reducing the throughput of the system. Further, the present handling system includes the ability to exchange one analyte for another, as testing requires, without interrupting the operation of the testing or reducing the throughput of the system. 
     A first carrier support member of the preferred embodiment, for example an aspiration platform, includes the first location and is disposed for access by a diagnostic module configured for performing the diagnostic process. The transporters can be configured for transporting the carriers from a loading bay to the first carrier support member and additionally to move the carriers between different locations on the first carrier support member. The transporter can preferably move the carriers to and from a plurality of first locations on the carrier support, for example, to position more than one carrier on the support member at any time. In an alternative embodiment, the first carrier support member can include a positioner that can be configured to receive and move the carriers for access by the diagnostic module for testing the contents of at least one of the plurality of the containers of the carrier. 
     Preferably, the identifying feature comprises an optically readable feature. The identification device can thus include an optical reader that is capable of reading this feature. The identifying features on the carriers preferably identify them as holding reagents or samples. Preferably, the individual samples and reagents can also be individually identified by the identification device. Alternatively, the carriers can be distinguished by other physical differences that can be detected by a sensor, or the different types of carriers can be in slightly different orientations to allow them to be identified by the position of the carrier. In another embodiment, the identifying feature is an identifiable physical characteristic, such as the height of the carrier. 
     A programmable controlling computer can control the movement of the transporter and other moving parts of the device based on input data and a pre-programmed priority order for processing the contents on the carriers. In a preferred embodiment, samples to be tested are loaded into the diagnostic system, and reagent carriers that hold containers with reagents are also loaded into the system. The reagent carriers are transported to reagent support members, such as on a carousel, automatically by a transporter. The samples are tested with the appropriate reagents depending on the test being conducted. 
     A preferred embodiment of a carrier includes at least one container holding portion that is configured for holding a container with a fluid substance, such as the samples or reagents. Preferably the carrier is configured to carry reagents, and may include a stirring member for moving at least one of the holding members with respect to the body of the carrier. The stirring member can include a first engagement portion that is engageable with a second engagement portion of the diagnostic analyzer for moving the container held by the holding portion with respect to the body of a carrier. This movement is preferably in response to relative motion between the carrier body and the second engagement portion. A plurality of holding portions can be provided on the carrier, and preferably fewer than all the holding portions are associated with the first engagement portion such that less than all of the containers are moved with respect to the body. This movement preferably provides for mixing or stirring the contents of the container. In a preferred embodiment, the first engagement member is configured for rotating the container that is associated therewith. The engagement member can be rotatable and configured to roll against the second engagement member. In one embodiment, the first engagement member includes a gear that is configured for meshing with teeth of the second engagement member, or a friction wheel that is in frictional engagement with the second member. In an embodiment in which the carriers are mounted on a carousel, the second engagement member can include a ring gear or friction wheel disposed adjacent a moveable portion of the carousel to mesh with the gear of or contact the friction wheel on the carrier. Thus, as the carousel rotates around the ring gear or friction wheel, the carrier gear or friction wheel causes a rotation of the container mounted therewith. The ratio between the ring gear and the carrier gear can be made at an integer to facilitate the reading of a bar code located on the reagent bottle when the reagent carriers are removed from the reagent carousel. 
     The preferred holding portions are configured for gripping the containers positioned thereon. Also, the body can have a handle portion to facilitate grasping the loaded carrier by hand. A transporter coupling portion can be provided as well for coupling with the transporter to enable the transporting of the carrier between different locations in the device. 
     In the preferred embodiment, a positioning device is configured for receiving and positioning the carriers for access by the diagnostic module. This positioning device is preferably provided for receiving the reagent carriers and includes the second location and is the second carrier support member. A retention member associated with the positioning device is configured for locking the carrier to the positioning device. The retention member is preferably operably associated with the transporter for releasing and including the carrier for the transporter to transport the carrier therefrom. This operative association can be provided by a mechanical connection activated by contact therebetween, an electrical connection, or it can be provided by the controlling computer, which tracks the positions of the transporter and the positioning device. 
     The preferred positioning device is a rotatably driven carousel that is driven to provide access to the contents of the carrier by the diagnostic module. An activation member of the preferred embodiment is operably associated with the transporter for releasing the carrier upon contact between the transporter and the activation member. A carrier-locking member is preferably configured for moving with respect to the carousel in association with the carrier to lock and unlock the carrier. The activation member is preferably displaced by the transporter to move the carrier-locking member to cause the locking and/or unlocking of the carrier. Preferably, the locking member displaces the carrier with respect to the carousel to move the carrier into a locked position. The carousel is preferably rotatable or otherwise movable with respect to the activation member, and the locking member is preferably mounted to the carousel. The activation and the locking member are disposed such that the activation member in the inactive position does not interfere with the locking member during the carousel rotation. 
     The retention member also preferably comprises a latching member configured for latching to a latchable portion of the carrier in the locked position, preferably upon relative movement between the latching member and the latchable portion. The locking member is preferably moveable with respect to the carousel and is associated with the carrier to move at least a portion of the carrier with respect to the latching member for locking and unlocking the carrier. Additionally, the locking member can have a tab that is received in the recess of the carrier to slide the carrier with respect to the latching member. 
     A carrier sensor can be provided for detecting the presence of the carrier on the positioning device. This carrier sensor can be, for example, a Hall effect, optical or a capacitive sensor. 
     Additional advantages of the invention will be realized and attained by the apparatus and method particularly pointed out in the written description and claims hereof, as well as from the appended drawings. It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the invention claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a preferred embodiment of the sample handling system of the present invention; 
         FIG. 2  is a top plan view of the sample handling system of  FIG. 1  with access doors removed; 
         FIG. 3  is a perspective view of a preferred embodiment of the sampling handling system with two diagnostic modules; 
         FIG. 4  is a top plan view of the sample handling system of  FIG. 3  with access doors removed; 
         FIG. 5  is a perspective view of a preferred embodiment of a carrier positioner; 
         FIG. 6  is a perspective view of a preferred embodiment of a transporter; 
         FIG. 7  is a top view of another embodiment of a diagnostic analyzer system according to the present invention; 
         FIG. 8  is a perspective view of an aspiration platform thereof, including a sample receiving tray; 
         FIG. 9  is a perspective view of a preferred embodiment of a reagent carrier; 
         FIGS. 10 and 11  are top and bottom perspective views, respectively, of a reagent positioning and locking system of the embodiment of  FIG. 7  in an unlocked position, with a carousel shown in  FIG. 10  in cross-section but hidden from  FIG. 11  for clarity; 
         FIGS. 12 and 13  are top and bottom perspective views, respectively, of the reagent carrier in a locked position, and 
         FIG. 14  is a front view of another preferred embodiment of a loading rack 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention relates to a random sample and reagent handling system for moving samples and reagents to and from a diagnostic module for automatic testing and retesting. The random handling system includes a loading rack for receiving a plurality of carriers. The carriers can include several tubes filled with samples. In a preferred embodiment, the sample carriers are arranged in a stationary linear array on a loading rack positioned in front of the diagnostic modules. The operator may load the carriers individually or in trays for convenient handling of multiple carriers. Individual carrier slots are provided for loading high priority or stat samples that require immediate processing. 
     A robotic device is provided to transport the carriers to and from the loading rack and to and from a carrier positioner adjacent the diagnostic module(s). The robotic device has an arm, which is controlled by a programmable computer, moving the carriers as required for testing and retesting. The system includes software that allows users to flexibly configure rules or criteria for retesting samples. These rules can also be utilized to change to another type of test depending on the results of a previous test. This can be a very cost effective approach that when utilized minimizes operator involvement in real time. The system also includes a software capability that can suspend the operation of the sampler handler in the event the user decides to change the test request(s) for a particular sample after loading the carrier. 
     The carrier positioner is located adjacent a diagnostic module for positioning the carriers so the samples selected for testing can be aspirated by a probe. The positioner includes a carriage connected to a lead screw driven by a stepping motor in response to commands from the programmable computer. In a preferred embodiment, the carrier positioner can accommodate at least two carriers, allowing the processing module to test one carrier while the transporter loads another carrier onto the positioner to maintain the system throughput. 
     A barcode reader is provided to read carrier and container identification. A bar code reader in the system reads bar coded labels attached to the carriers and the sample tubes or reagent bottles as the robotic device passes the carriers by the reader. 
     Only one robotic device and barcode reader are preferably used for the present system, regardless of size. The invention can be dynamically configured for variable queue sizing depending on the user&#39;s particular workload. Additionally, the total capacity of the system can be changed based on peak loading requirements that vary across testing segments in the laboratory. 
     In operation, the robotic arm picks up a carrier from the loading rack and travels past the bar code reader to identify the carrier and samples. Tests previously programmed in the computer are assigned to each tube in the carrier. The robotic arm delivers the carrier to be tested to the carrier positioner. The positioner is controlled by the computer to move the carrier to a predetermined location adjacent a pipetter on the diagnostic module. The pipetter aspirates samples from the tube for testing. When the tests are completed on all the tubes in the carrier, the robotic arm loads the carrier and returns the carrier to its designated location in the loading rack. While the tubes of one carrier are being aspirated, a second carrier can be moved to the carriage. 
     The carrier handling system can include more than one diagnostic module. For example in one preferred embodiment, the carrier handling system includes two diagnostic modules, a clinical chemistry test module and an immunoassay module. A carrier positioner is provided for each diagnostic module in the system. 
     The present invention provides a modular random sampling system that can be adapted to a variety of diagnostic modules. The present carrier handling system is modular and scalable to different sizes of processing modules and may be used for single or multiple module systems. The system provides random access to carriers on the loading rack. This random access capability allows the system to access and process high priority samples rapidly. This capability also allows the system to balance the workload of multiple processing modules with different throughput capabilities. After samples are processed initially, the sample carriers are returned to their slots in the loading area and then accessed again when the initial testing is complete to provide automated retest capability. This automated retest capability does not require any additional intervention by the operator. Random access assures the samples to be retested can be processed in the shortest possible time. The system is mechanically simple, which minimizes system cost and maximizes system reliability. The present system is self-contained and can be assembled and tested independently of the processing modules for ease of manufacture and installation in the field. 
     A system is also provided that processes samples for testing and retesting in a faster time and with more reliability than previous handling systems. The sample handling system of the invention can additionally provide faster processing of high priority samples while maintaining throughput of routine test samples. 
     A system can be provided having a robotic assembly for moving a carrier with a plurality of test samples from a loading rack to a sample testing area and returning the carrier to the loading rack and having a programmable computer for (1) controlling the robotic assembly, (2) selecting carriers for testing based on predetermined priority, (3) achieving positive identification of the carriers and samples, and (4) identifying a breach of positive identification when an access door has been opened or a carrier has been removed prematurely. 
     A preferred embodiment of the invention is a carrier handling system, generally designated by the numeral  10 . As shown in  FIGS. 1 and 2 , the present handling system  10  includes a loading rack  30  with a plurality of slots  32  for receiving a plurality of carriers  40 . Each carrier  40  can hold a plurality of containers  42 , such as tubes or cups, filled with samples. In this example, each carrier  40  can hold five tubes  42 . However, the carriers  40  can be configured to hold either more or less tubes  42  depending on the system requirements. 
     The sample carriers  40  are arranged on the loading rack  30  in a stationary linear array near the processing modules  20 . The operator can load the carriers  40  onto the loading rack or platform  30  of a loading bay individually into slots  32  or in trays  35  for convenient handling of multiple carriers. The loading rack  30  can be configured in different shapes such as circular with slots aligned around the circular tray. The loading rack  30  includes a routine loading area  31  and an urgent or stat sample area  33 . In a preferred embodiment of the present invention, the routine loading area  31  comprises a plurality of bays  36 , each bay  36  accommodating a tray  35 . Each bay  36  includes a door  38  attached to the loading rack  30 . Each door  38  includes a latch that is automatically released by insertion of a tray  35 . This latch is preferably difficult to actuate by hand to prevent an operator from affecting the operation of the carriers  40 . 
     The carriers  40  may be loaded onto a tray  35  before loading the tray  35  into the loading rack  30  from the front  12  of the handling system  10 . Alternatively, a carrier can be loaded onto the tray previously loaded onto the loading rack  30 . In this example, a tray  35  accommodates up to five carriers and the loading rack accommodates seven stat carriers  40  and four routine trays  35  holding up to 25 samples each. However, the loading rack  30  may be configured differently to accommodate peak loading requirements that vary across testing segments in the laboratory. 
     The carriers  40  are positioned in the tray slots until selected for testing or retesting. A carrier  40  is released for unloading immediately after retest or after all tests in the carrier  40  are complete and no retests are required. A tray  35  is released for unloading when all the carriers  40  in the tray  35  are released for unloading. A high priority or stat carrier  40  is loaded into the high priority sample area  33 . A carrier  40  located in the high priority area  33  is transferred to the carrier positioner  80  for aspiration and then is returned to the stat area  33  until a programmable computer  60  determines if a retest is needed. A stat carrier  40  is released for unloading after all tests are completed and any retest requests are aspirated. 
     A plurality of status indicators  74  are provided to indicate to the operator when a completed tray  35  or an individual carrier  40  in the high priority area  33  may be removed. For example, the status indicator light  74  is green to indicate the corresponding tray  35  or carrier  40  can be accessed or the status indicator light  74  is amber to indicate the tray  35  or carrier  40  is in process and should be left in place until completed. 
     The present sample handling system  10  includes a means for detecting that a new tray  35  or new carrier  40  in the high priority area has been loaded. A loading rack sensor  98  (not shown) is located in each bay or stat slot to detect the presence of a tray or carrier respectively. If a new tray is detected the contents of the tray  35  are scanned by a first sensor  102  on the carrier transporter  50  to determine if any carriers are in the tray. 
     In a preferred embodiment, the sample handling system  10  includes a carrier transporter  50  that consists of a robotic device having a robotic arm  52  to move the carriers as required for testing and retesting (see  FIG. 6 ). The robotic arm  52  has a gripper device  54  that picks up the carrier  40  by a support tab  48 . The robotic transporter  50  includes a drive motor  58  that is controlled by a programmable computer  60 . In the preferred embodiment, the robotic arm  52  traverses the length of the loading platform  30  by a timing belt  56 . However, it is understood by a person skilled in this art that other means can be used to move the robotic arm  52 . 
     The transporter  50  is capable of lifting a carrier  40  a height just slightly more than the total height of the carrier  40  holding a tube  42  in the loading rack  30 . The vertical motion of the transporter  50  is created by a lead screw  90  driven by a stepping motor  92 . The robot transporter  50  can also rotate a carrier  40  through a 210 degree range of motion between positions for barcode reading, access to carrier slots, access to a carrier positioner  80 , and access to a reagent storage location. The rotational motion of the transporter  50  is provided by a spline shaft  96  coupled to a stepping motor  97 . The spline shaft  96  allows the robotic arm  52  to move vertically while maintaining accurate angular positioning. Although the preferred embodiment includes specific means to move the robotic transporter, it is understood by a person skilled in this art that other means could be used to move the transporter  50 . 
     The present sample handling system  10  also includes a carrier positioner  80  located adjacent a diagnostic module  20  for conducting tests on the samples in the test tubes  42  (see  FIG. 5 ). In the preferred embodiment, the carrier positioner  80  has a plurality of openings  86  for receiving carriers. The positioner  80  can position at least two complete carriers underneath the testing point(s) of a processing module, allowing the processing module to aspirate from one carrier  40  while the transporter  50  loads another carrier  40  on the positioner  80  to maintain system throughput. The carrier positioner  80  includes a carriage  81  on a lead screw  82  driven by a stepping motor  84  in response to commands of the computer  60 . Although in the preferred embodiment the positioner  80  is driven by a lead screw  88 , the positioner  80  could be driven by other known driving means such as a belt, a chain, an air cylinder, or a linear motor. The positioner  80  may be a variety of configurations, including having multiple openings  86  for routine carriers and high priority carriers. 
     In a preferred embodiment, the carrier positioner  80  has four openings  86  to accommodate the needs of several different types of processing modules using common hardware to reduce the overall product cost of the system (see  FIG. 5 ). The positioner  80  is configured to adapt to a variety of diagnostic modules  20 . For example, two openings may be used for one pipetter and the other two openings for a different pipetter in the same diagnostic module  20 . Alternatively, two openings may accommodate solely high priority sample carriers while the other two openings accommodate routine sample carriers. 
     The robot transporter  50  executes the following six basic carrier handling operations: 1) pick up carrier  40  from loading rack  30 ; 2) place carrier  40  into loading rack  30 ; 3) place carrier  40  onto positioner  80 ; 4) pick up carrier  40  from positioner  80 ; 5) present carrier  40  to a barcode reader  70 ; and 6) scan trays  35  for carriers  40 . 
     In a preferred embodiment of the present invention, the robot transporter  50  includes nine sensors for monitoring the correct operation of the system. Due to the unique value and hazards of the biological samples being transported, a high degree of capability to monitor and verify the operation of the transporter  50  is important. A first reflective sensor  102  on the transporter  50  is used to determine the presence of a carrier  40  in a tray  35  or slot  32 . A second (carrier slot alignment) sensor  104  is used to verify correct alignment between the transporter  50  and the carrier slots on the loading rack for pick up and placement of the carriers. A third (carrier positioner alignment) sensor  106  is used to verify alignment between the transporter and the openings  86  in the positioner  80 . A fourth reflective sensor  107  is used to determine if a carrier  40  is present on the positioner  80 . The horizontal, rotational, and vertical motions of the transporter  50  are monitored by fifth, sixth, and seventh sensors  108 , 110 , 112 . An eighth sensor  114 , positioned with the rotational motion sensor  110 , is used to verify the correct rotational position of the robotic arm  52 . Located on the robotic arm  52  is a ninth sensor  116  used to verify that the carrier  40  is properly engaged in the arm  52  for safe transport. Although the preferred embodiment includes the above-described nine sensors, it is understood by a person skilled in this art that other means could be used to monitor and verify the operation of the transporter  50  and the robotic arm  52 . 
     A bar code reader  70  is included in the present sample handling system to read carrier and sample identification. Bar coded labels are attached to the carriers  40  and, optionally on the sample tubes  42 . The carrier  40  is scanned once with a barcode reader  70  when the carrier  40  is first selected. After being scanned, the carrier  40  is moved by only the transporter  50  or the linear positioner  80 . At this point, all motions of the carrier  40  generate position and alignment feedback to the computer  60 , so the carrier identification only needs to be read by the barcode reader  70  once. 
     Many types of diagnostic modules  20  can be employed with the present random sampling handling system  10 , including immunoassay modules or clinical chemistry test modules. Examples of suitable diagnostic modules include ARCHITECT® i 1000, i2000, and c8000 processing modules, manufactured by Abbott Laboratories, Abbott Park, Ill. 
     In a preferred embodiment of the sample handling system  10  a plurality of access covers  94  are positioned over the loading rack  30 . When an access door  94  is opened, an interlock connected to the access cover  94  preferably will indicate a breach of positive identification, preferably requiring the barcode reader  70  to rescan the carriers  40 . 
     During operation of the present carrier handling system  10 , an operator loads the trays  30  or individual carriers  40  onto the loading rack  30 . Either the operator inputs into the computer the patient sample identification and the test orders or this information may be downloaded into the computer  60  from a lab information system. A test order may require a plurality of separate assays. Once a sample is loaded, the programmable computer  60  determines the order of the different sample tests based on a preprogrammed priority. The system detects the presence of the carriers  40  and selects one for sampling. The computer  60  activates the robotic transporter  50  to pick up the selected carrier  40  from the loading rack  30  and transport the carrier  40  past the bar code reader  70  to identify the carrier  40  and the sample tubes  42 , the bar code data is sent to the programmable computer  60 . Tests previously programmed in the computer  60  are assigned to each tube  42  in the carrier  40 . The transporter  50  then delivers the carrier  40  to the positioner  80 . Software in the computer  60  controls the movement of the positioner  80 , moving the carrier  40  to a predetermined location adjacent a testing site or pipetter on the diagnostic module  20 . The pipetter withdraws the sample from a tube  42  for testing. 
     When the tests are completed on all the tubes  42  in the carrier  40 , the robotic arm  52  loads the carrier  40  and then moves and returns the carrier  40  to its assigned location on the loading rack  30 . While the tubes  42  of one carrier  40  are being aspirated, a second carrier  40  can be loaded onto the carriage  81  for testing. At this point, the status indicator  74  will show a hold status for the carrier  40  until the computer  60  makes the retest decision. If a retest is needed, the carrier  40  will be selected again with the same process described above, but without a bar code scan. The robot  50  continues to pick up carriers  40 , scan and place the carriers  40  as required. The status indicator  74  at each tray  35  or slot  32  will show a completed tray of carriers  35  or carrier  40  when retesting is not required. The operator should remove the completed carrier  40  or tray of carriers  35  when they have been released for unloading. 
     Positive identification of the carriers preferably is considered violated if an access cover  94  of the sample handling system  10  is opened. When an access door  94  is opened all carriers  40  preferably must be rescanned before further testing to provide positive identification. Further, positive identification of a carrier  40  is violated if a carrier  40  or a tray  35  on the loading rack  30  is removed prematurely. At this point the carrier  40  or tray  35  that was removed prematurely preferably must be replaced and rescanned. Slot and tray sensors  98  are monitored continuously to identify such violation of the positive identification. The programmable computer  60  rapidly checks the status of each individual tray or carrier sensor  98  in sequence. If a change in sensor state is observed, the computer  60  can determine that a carrier  40  or tray  35  has been removed and the identity of the contents can no longer be assured until the carriers  40  in question are re-scanned. 
     In the preferred embodiment, the robot arm  52  cannot access the linear positioner  80  while it is moving. For example, if the positioner  80  accommodates two carriers  40 , and two carriers  40  are already on the positioner  80 , no preemption is allowed for a high priority or stat sample. The high priority testing preferably must wait until the carrier  40  in process is complete. At this point, the completed carrier  40  may be unloaded, the stat sample will be loaded and processed immediately. However, if only one carrier  40  is on the positioner  80 , the stat or priority carrier may be loaded immediately and after the current sample is completed, the stat or priority carrier will be positioned for aspiration. Aspiration will resume on the remaining routine samples after all the tube samples on the stat carrier are aspirated. 
     The computer software preferably includes a preprogrammed or programmable priority order for processing samples. For example, the carriers can be selected for processing according to the following priority: 1—unload completed carriers; 2 move aspirated carriers to the loading rack; 3—stat or priority retests; 4—stat or priority tests; 5 stat or priority carrier pick, scan and move to holding area; 6—routine retests; 7—routine tests; 8—routine carrier pick, scan &amp; move to holding area. This ordering of sample priorities has been shown to result in rapid response to high priority samples and maintaining high system throughput. It is understood by one skilled in the art that other priority schemes may be implemented to achieve different levels of performance and responsiveness. 
     Another preferred embodiment of the carrier handling system is shown in  FIGS. 3 and 4  with a plurality of diagnostic modules  20 . This alternative embodiment is very similar to that depicted in  FIGS. 1 and 2 . Accordingly, like numerals in  FIGS. 3 and 4  indicate the same elements as defined in connection with  FIGS. 1 and 2 . 
     The carrier handling system  10 ′ in  FIGS. 3 and 4  includes at least two diagnostic modules. The diagnostic modules  20  could include immunoassay, clinical chemistry, hematology, or other known diagnostic modules, or a combination of these modules. A carrier positioner  80  is provided for each diagnostic module  20 . A sample handling system  10 ′ with a plurality of diagnostic modules  20  enhances the productivity in a lab. Further a multiple module system reduces the requirement to separate or aliquot samples for distribution to different systems. In the present system, samples can be tested with the different modules without removing them from the system. This multiple module system also reduces the space requirements in a lab and can lower the costs of operation. 
     As shown in  FIG. 3 , a preferred embodiment of the carrier handler system  10 ′ includes a loading rack  30  having seven urgent or priority carrier slots  32  and  12  bays  36  for receiving routine trays  35  holding five carriers  40  each. 
     Only one carrier transporter  50  and barcode reader  70  are preferably used for the present system, regardless of size. Appropriate control software is used for the present system to select carriers  40  for testing and retesting based on a predetermined priority, direct the operation of the mechanisms, and monitor the system for correct operation. 
     The present sample handling system is modular and scalable to different sizes of processing modules and may be used for single and dual module systems. The system provides random access to sample carriers in the loading platform. This random access capability allows the system to access and process high priority samples rapidly. This capability also allows the system to balance the workload of two processing modules with different throughput capabilities. After samples are processed initially, the samples can be returned to the loading platform and then accessed again when the initial testing is complete to provide automated retest capability. This automated retest capability preferably does not require any additional intervention by the operator. Random access assures the samples to be retested can be processed in the shortest possible time. The system is mechanically simple, which minimizes system cost and maximizes system reliability. The present system is self contained and can be assembled and tested independently of the processing modules for ease of manufacture and installation in the field. 
     Several features are included in the present sample handling system to prevent incorrect carrier placement. First, the second and third sensors  104  and  106  on the transporter  50  verify correct alignment of the carrier  40  with the linear positioner  80  and the loading rack  30  respectively. In addition, the first sensor  102  verifies the presence of a carrier  40  on the loading rack  30  and the fourth sensor  107  (not shown) verifies the presence of a carrier  40  on the positioner  80 . Further, the system includes frequent software verification of the operation of the sensors. 
     Referring to  FIG. 7 , another embodiment of a diagnostic analyzer system includes a loading bay  120  with a loading tray, which is configured to receive both sample and reagent containers  122 , 124 . To insure stability of samples and reagents refrigeration may be included in the loading tray area. Preferably, the sample and reagent containers  122 , 124  are held in sample and reagent carriers  126 , 128 , respectively. Robotic transporter  130  is configured for linking to and transporting both the sample and reagent carriers  126 , 128 . The robot transporter  50  can rotate a carrier  40  through a 210 degree range of motion between positions for barcode reading, access to carrier slots, access to a carrier positioner  80 , and access to the reagent storage location. The transporter  130  preferably has random access to any of the sample carriers  126  or reagent carriers  128 , regardless of where they are positioned in the loading bay  120 . In  FIG. 7 , the reagent carriers  128  are shown in groups to the right of the sample carriers  126 , but the preferred transporter  130  and loading bay  120  can accommodate the carriers  126 , 128  in any position and in any order, even with reagent carriers  128  interspersed between sample carriers  120 . In an alternative embodiment, however, separate bays are provided for sample carriers  126  and reagent carriers  128 . 
     The preferred embodiment preferably has an aspiration tray with a sample positioning shelf  132 , as shown in  FIG. 8 , which can be free of any mechanism to move the sample carrier therealong. The transporter  130  is preferably configured to reposition the sample carriers  126  along the shelf  132  as needed for access by the diagnostic module  136 . The sample container  122  that is to be accessed by the pipetter  134  of the diagnostic module  136  is positioned in a pipetting location, which is preferably adjacent a notch  138  in an upright wall of the shelf  132 . The notch  138  is configured to receive the end of the pipetter  134  as it is moved downwardly towards the contents of the sample container  122 . For access to other sample containers  122  and the sample carrier  126 , the transporter  130  repositions the sample carriers  120  along the shelf  132 . The shelf  132  is preferably sufficiently large to accommodate a plurality of sample carriers  126 , each of which can be repositioned by the transporter as needed for access by the pipetter  134 . Shelf  132  preferably has a bottom support surface  142  and a front upright wall  144  that is sufficiently high to prevent the sample carrier  126  from sliding off the shelf, as well as an upright back wall  146 . The back wall  146  is preferably taller than the front wall  144 , the carrier  126 , and any containers  122  that are held in the carrier  126 , and promotes sterility in the diagnostic module  136 , which is preferably disposed behind the back wall  146 . 
     In the preferred embodiment, the sample carrier  126  has slots  140  aligned axially with respect to the openings in which the sample containers  122  are carried. The slots  140  permit scanning of a bar code or other identifying feature that is present on the containers  122 . In an alternative embodiment, another bar code or other identifying feature can also or alternatively be present on the sample carrier  126  itself. 
     A preferred embodiment of a reagent carrier  128  is shown in  FIG. 9 . The carrier  128  has a carrier body  150  that includes holding portions  152 - 154 , each of which is configured for holding a reagent container  124 . The three holding portions  152 - 154  preferably have a structure for a snap-fit connection to the base of a container  124 . Holding portion  154  additionally includes nubs  156 , which can be supported on upstanding posts  158  and which are configured to clip about an enlarged diameter portion of the base of an alternative reagent container (not shown) that does not have the snap-fit features located on other reagent containers. 
     Holding portion  152  is configured for moving with respect to the carrier body  150  to move a reagent container  124  that is attached thereto for a constant mixing or stirring effect. This is desirable, for example, when the reagent includes microparticles that require constant motion to maintain a generally homogenous suspension. This holding portion  152  is movable with respect to the body  150  to produce this relative motion. 
     An engagement portion, such as gear  170 , is coupled or otherwise associated with holding portion  152 , such that the gear  170  is drivable by a member external to the carrier body  150  to rotate holding portion  152 . Preferably, the gear  170  is connected by a shaft  172  to the rotatable holding portion  152 , as shown in  FIG. 10 . In an alternative embodiment, a different type of engagement portion can be used, or an on-board drive, such as a motor, can be mounted to the reagent carrier body  150 . Although in the preferred embodiment, only one of the holding portions is rotatable or movable with respect to the carrier  128  for producing the stirring in the reagent containers  124 , in other embodiments, more than one of the holding portions can be rotatable and more than one can be associated with the gear  170  for driving the motion relative to the carrier body. 
     The gear  170  preferably is disposed near one end of the carrier body  150 , preferably opposite from transporter coupling  162 , described below. The gear  170  preferably is exposed on a lower side of the carrier body  150 , on an opposite side from the part of the holding portions that are configured for connecting to the containers  124 . Holding portion  152  can be elevated with respect to holding portions  153 ,  154 , and preferably accommodates a container  124  that is shorter than the containers  124  placed on the other holding portions  153 ,  154 , preferably to position the upper ends of the containers  124  at substantially the same height. 
     One end of the carrier body  150  includes a handle portion  160  to facilitate grasping or holding of the loaded carrier by hand by a user. The handle portion  150  preferably is configured as a curved inverted hook with a space large enough to comfortably receive at least one figure of the user. Preferably at the opposite end of the carrier body  150  from the handle portion  160 , a transporter coupling  162  is provided, which is preferably similar to a transporter coupling  145  of the sample carrier  126  shown in  FIG. 8 . The transporter coupling  162  of the preferred embodiment includes an angular hook portion that the transporter is capable of coupling to for lifting, maneuvering, and transporting the carrier to different parts of the diagnostic system. 
     The preferred reagent carrier  128  additionally has an identifying feature, such as a bar code  164 . The identifying feature can be a one- or two-dimensional bar code, such as a Code 128 type barcode, or other feature that can be identified by the system. Referring again to  FIG. 7 , the system includes an identification device which can have a bar code reader  166  or other identification device adapted to interpret and identify information of an identifying feature on the carriers  126  and/or the containers  124 . In another embodiment, the identifying feature is disposed on the containers  124 , and can by accessed or read by the identification device when the containers  124  are loaded on the carrier  128 . In yet another embodiment, the identification device is associated with the transporter  130  such that an action of the transporter  130  can identify the type of contents in the containers  124  on each carrier  128 . For instance, the transporter  130  can be provided with a sensor mounted thereon that can sense an identifying feature on the carriers  128  or containers  124 . Alternatively, to provide an initial identification of the type of contents, the transporter can sense the physical dimensions of the carriers it is picking up. For instance, the vertical height of the reagent carriers  128  or a portion thereof can be different than the height of the sample carriers  126 . In one embodiment the height at which the sample and regent containers are held in the carriers in the loading bay is different and sensed by the identification device to initially determine whether the contents are reagents or samples. As shown in  FIG. 14 , loading tray pockets  302  catch the wider reagent container base  304 , but do not catch the narrower sample carrier base  306 . Thus, the reagent container is positioned higher than the sample carrier within the loading tray. The height at which the transporter  130  contacts or engages to lift the respective carrier  126 , 128  is used by the controlling computer to identify the contents as samples or reagents. In one embodiment, an initial determination of the type of contents is made, such as by determining the height of the carrier transported, and an additional positive and individual identification is made of the contents subsequently, such as by the barcode reader. 
     In the preferred embodiment, the bar code reader used can read both one- and two-dimensional bar codes, as one-dimensional bar codes are preferably used on the sample containers, while two-dimensional bar codes are used on the reagent carriers. As discussed above, other types of identifying features can be used, and the reagent containers  124  and sample carriers  126  can additionally be labeled with identifying features. 
     When the transporter  130  is directed by the controlling computer to pick up a carrier  126 ,  128 , it positions the carrier  126 , 128  for scanning by the bar code reader  166 . This enables the system to determine the type of contents that are carried on the carrier. If the system determines that the transported carrier is a sample carrier  126 , then the transporter  130  will position the carrier  126  in the appropriate location on the aspiration tray shelf  132 . On the other hand, if the system determines that a reagent carrier  128  is being transported, than that carrier  128  can be positioned in a reagent positioning area. The preferred reagent positioning area includes a carousel  168 , which is configured to move and preferably rotate about its axis to position the reagents thereon in a location in which they can be accessed when needed by the pipetter  134 . The carousel  168  of the preferred embodiment has one or more platforms  174  that form bays in which the reagent carriers  128  are received, as shown in  FIG. 10 . Retention members, which include a first portion associated with the bays, are configured for locking the carriers  128  to the carousel  168  and releasing them for the transporter  130  to retrieve and transport the carriers  128  to a different location in the device when they are no longer needed on the carousel  168  such as when the reagents thereon have been used up. The portion of the retention member that is disposed on the carousel  168  preferably comprises fixed stirrups  176  that form a loop with an opening extending radially therethrough with respect to the carousel  168 . Stirrups  176  are positioned in dimensions to correspond with feet  178  of a second portion of the retaining member, which are associated with the carrier body  150  and feet  178 , preferably extending downwardly from the body  150 , as shown in  FIG. 11 . The feet  178  of the preferred embodiment preferably extend downwardly no further than the remaining lowest portion of the carrier  128 , which in the preferred embodiment is the lowest portion of the carrier body  150 . This enables the carrier  128  to be placed in a flat surface when not being used in the device. 
     The transporter  130  is operated to lower the carriers  128  onto the carousel  168 , preferably with the feet  178  radially aligned with the stirrups  176 . When the carrier  128  is slid radially towards the axis of the carousel  168 , the feet are received within the opening in the stirrups  176  in an association such that the stirrups  176  retain the feet  178  against axial or upward removal from the carousel  168 . Together, the feet  178  and stirrups  176  comprise latchable portions that latch together to assist in substantially locking the carrier  128  to the carousel  168 . 
     Referring to  FIGS. 10-13 , an activation member  180  is positioned and configured adjacent the carousel  168  for operation by the transporter  130  to control the retention members. In the preferred embodiment, the activation member  180  includes a bar  182  that is accessible by the transporter  130 , such that when the transporter  130  moves adjacent the carousel  168 , the bar  182  is depressed into the carousel  168 . Bar  182  is preferably pivotably attached to a lever  184  that is pivotable about axis  186 . At the other end of the lever  184  is a rod  188  that preferably protrudes generally axially for contacting a locking member  190 . The activation member  180  and the locking member  190  are preferably disposed beneath the carousel  168  on a side opposite from the carrier  128 . 
     As shown in  FIG. 10 , when the transporter  130  moves towards the carousel  168 , a surface  196  of the transporter  130  presses against bar  182 , which causes the lever  184  to pivot about axis  186 . The bar  182  is guided by a pin  198  that is received in an elongated groove  200  of the bar  182  on its lower side. When the lever  184  pivots, the rod  188  displaces the locking member  190  radially away from the axis of the carousel  168 . 
     The locking member  190  preferably has a tab  192  that extends upwardly through the platforms  174  and protrudes on the upper side of the carousel  168 . The transporter  130  lowers the carrier  128  so that the tab  192  is received in an opening  194  of the carrier  128 . With the carrier  128  seated on the carousel  168  and the tab  192  received in the opening  194 , the transporter  130  moves away from the carousel to perform another transporting operation on a different carrier  126 , 128 . When this happens, spring  202  resiliently biases the lever  180  to a position permitting the locking of the carrier  128  to the carousel. Additionally, the locking member  190  has a guide shaft  204  about which is mounted a spring  206 . When rod  188  moves radially towards the axis of the carousel  168 , spring  202  resiliently returns the lever  184  to its original position, and tab  192  displaces the carrier  128  along the platform  174 , thus also displacing the feet  178  towards the axis of the carousel  168 . This motion causes the feet  178  to latchedly enter the stirrups  176 , and together with the locking tab  194 , substantially lock the carrier  128  to the carousel  168 . 
     In the preferred embodiment, the physical contact of the transporter  130  against the activation member mechanically displaces and operates the activation member to lock or unlock the carrier  128  to or from the carousel  168 . In another embodiment, the contact between the transporter  130  and the activation member can cause an electrically or otherwise driven mechanism to lock or unlock the carrier. In one embodiment, a solenoid or motor operates the locking member, and this can be completely controlled by the controlling computer, without directly being activated by any physical contact from the transporter  130 . 
     The same motion of the carrier  128  towards the locked position caused by the locking member  190  preferably also meshes gear  170  with an engagement portion that is associated with the carousel  168 . This engagement portion is preferably associated with the carousel  168 , and in the preferred embodiment comprises a ring gear  208  that is preferably stationary. With the gear  170  and ring gear  208  meshed, rotation of the carousel  168  about the ring gear  208  spins both the gear  170  and the container  124  mounted to holding portion  152 . As seen in  FIG. 12 , the preferred container  124  includes internal ribs  210 , which improve stirring and mixing of the contents therein. 
     The actuation portion  180  is preferably mounted to a stationary portion of the device that does not rotate with the carousel  168 . The locking members  190  and the rod  188  are resiliently biased by springs  202 , 206  to positions so that rod  188  is aligned with gaps adjacent the locking members, which are aligned circumferentially along the carousel  168 . Thus, as the carousel  168  rotates, the rod  188  passes adjacent to the locking members  190 , preferably without coming in contact therewith, and substantially without interfering with or causing the locking members  190  to move from their locked positions. 
     As shown in  FIGS. 10 and 12 , a carrier sensor  212  is preferably mounted on a fixed portion in the interior of the carousel  168 . The carrier sensor  212  is configured for detecting the presence of a carrier  128  on the carousel  168  or a carrier  128  in the locked position on the carousel  168 . The preferred carrier sensor  212  is a Hall effect sensor that is configured to detect the presence of a magnet  213  embedded in the handle portion  160  of the carrier  128 . Alternatively, other kinds of sensors can be used, such as a capacitive sensor to directly detect the presence of the carrier material, which is preferably plastic. The sensor  212  preferably transmits a signal to the controlling computer to indicate the presence or absence of the carrier  128  in the locked position on the carousel  168  at the loading location, where the transporter  130  can load the reagent carrier  128  onto the carousel  168 . 
     In the operation of the device, the controlling computer keeps track of the position on the carousels  128  holding each reagent in the reagent containers  124 . The pipetter  134  preferably has a pivoting arm  214  that can pivot along an arc  216 . The rotational position of the carousel  168  and the pivoting arm  214  are controlled by the controlling computer to intersect the selected reagent container with the locus of the pipetter  134 . Thus, the pipetter can draw the desired amount of reagent to transmit it to a diagnostic testing area  218  of the diagnostic module. The pivoting arm  214  is also movable to position the pipetter over the sample container  122  from which a sample is to be drawn, and the drawn sample can also be delivered to a diagnostic testing area  218 . 
     It is understood that the foregoing detailed description and accompanying examples are merely illustrative and are not to be taken as limitations upon the scope of the invention, which is defined solely by the appended claims and their equivalents. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. For example, reagent positioning devices other then carousels can be used for positioning the reagents and desired location for access by the pipetter, and the ring gear that drives the gear on the carrier to rotate one of the holders can also be driven to rotate without requiring any motion from the carousel to mix the microparticles or any other substance in the storage container.