Patent Application
20090274348
The application relates to the field of immunodiagnostic testing and more particularly to an automated testing apparatus having at least one imager disposed in relative proximity to a centrifuge used for supporting at least one test sample. The at least one imager is configured to provide images of test samples in order to enable enhanced processing in advance of a fully completed centrifugation cycle.
Immunological agglutination reactions are used for identifying various kinds of blood types as well as for detecting various kinds of antibodies and antigens in blood samples and other aqueous solutions. In such procedures, a sample of red blood cells is mixed with serum or plasma in either test tubes or microplates, wherein the mixture is incubated and then centrifuged. Various reactions then occur or do not occur depending on, for example, the blood types of the red blood cells or whether certain antibodies are present within the blood sample. These reactions manifest themselves as clumps of cells or as particles with antigens or antibodies on their surfaces, referred to as agglutinates. The failure of any agglutinates to appear indicates no reaction has occurred, while the presence of agglutinates, depending on the size and amount of the clumps formed, indicates the presence of a reaction and the level of concentration in the sample and reaction strength.
Rather than using microplates or test tubes, another form of agglutination test method has been more recently utilized, as is described in U.S. Pat. No. 5,512,432 to LaPierre et al. According to this method, gel or glass bead microparticles are contained within a small column, referred to as a microcolumn or a microtube. A reagent, such as antibody for detecting “A” antigen, is dispensed in a diluent in the microcolumn and test red blood cells, which may or may not contain “A” antigen, are placed in the reaction chamber above the column. The column, which is typically one of a plurality of columns formed in a transparent card or cassette, is then centrifuged. The centrifugation accelerates the reaction, if any, between the red blood cells and the reagent, and also urges any cells toward the bottom of the column. In the meantime, the glass beads or the gel material acts as a filter, and resists or impedes downward movement of the particles in the column. As a result, the nature and distribution of the particles in the microcolumn provides a visual indication of whether any agglutination reaction has occurred, and if such a reaction has occurred, the strength of the reaction based on the relative position of the agglutinates in the column.
If no agglutination reaction has occurred, then all or virtually all of the red blood cells in the column will pass downward during the centrifugation procedure, to the bottom of the column in the form of a pellet. Conversely and if there is a strong reaction between the reagent and the red blood cells, then virtually all of the red blood cells will agglutinate, and large groupings will form at the top of the microtube above the gel or bead matrix in that the matrix is sized not to let these clumps pass through. Reactions falling between these latter two extremes are possible in which some but not all of the red blood cells will have agglutinated. The percentage of red blood cells that agglutinate and the size of the agglutinated particles each have a relationship with the strength of the reaction. Following the centrifugation process and after all processing steps have been completed, the microtube is visually examined by either a human operator or by machine vision and the reaction between the red blood cells and the reagent is then classified. The reaction is classified as being either positive or negative, and if positive, the reaction is further typically classified into one of four classes depending on the strength of the reaction.
Automated immunodiagnostic testing apparatus or systems have been designed that are used for the handling, testing and evaluation of “gel cards”, “bead cassettes” or other forms of test elements such as described above that employ column agglutination technology. In a typical automated apparatus, a control module or station having at least one imager and a connected processor is used to evaluate the results of testing following the completion of a centrifugation cycle, this cycle typically lasting between about 10 and 30 minutes. Following centrifugation in conventionally known apparatus, the test elements must first be removed from the centrifuge and then relocated within the control station of the apparatus or the test element can be removed from the centrifuge and evaluated manually to determine the extent of the agglutination reaction, if any.
A general and continuing problem in the field of immunodiagnostic testing is that of improving throughput and processing time, particularly with automated analysis systems or apparatus. In addition and for similar reasons, it is desirable to terminate testing if, for example, a failure mode occurs that would produce an obviously incorrect result and waste considerable time, if centrifugation were to proceed over its complete typical time cycle. It is believed that there are methods to determine or predict certain test results (e.g., strong positive or strong negative reactions) in advance of a complete centrifugation cycle.
According to one aspect, there is disclosed an immunodiagnostic testing apparatus comprising a centrifuge and at least one imager that is disposed in proximity to the centrifuge such that at least one image can be captured of at least one test element during centrifugation and prior to the conclusion of a predetermined centrifugation time period. The test element is capable of producing a perceivable agglutination reaction that can be graded, wherein the agglutination reaction is being accelerated by centrifugation and wherein at least one captured image of said test element is taken prior to the conclusion of a predetermined centrifugation period and used by means of the apparatus as to the processing of at least one test element.
In one version, the imager can capture a single image or multiple images of the at least one test element, such as a gel card or bead cassette, during the course of a centrifugation process such that a predicted value of a gradable agglutination reaction can be obtained. If adequate predictive data can be obtained, the centrifugation process can be stopped before the completion time of a typical centrifugation period. In one version, a rate of change in the reaction can be detected by inspection of captured images, either in sequence or in comparison to a standard image. For example and according to one version, a rate of change can determined whether on the basis of distance traveled over time to predict an endpoint of the reaction. Alternatively, the at least one captured image can be used to determine whether a failure mode exists, for example, either in the test element or in the process itself. An illumination source is provided that can be activated for the purposes of imaging, such as a strobe lamp or other controllable light source. In one version, a strobe lamp and an imager are each synchronized with the rotation of the centrifuge with the imager being preferably disposed in a fixed position. The illumination source can be integral with the at least one imager or disposed in relative proximity therewith.
In one version, the imager can operate dynamically; that is, “on the fly”, to provide data while the centrifuge is still in operation. According to another version, the centrifuge can be stopped at an intermediate point during the test cycle and the imager can then be used to capture at least one image, wherein the at least one captured image can be evaluated before tests are resumed. In this latter version, the image of the test element can be captured either within the centrifuge or the centrifuge can be stopped and the test element removed for evaluation. Depending on the results of this evaluation, the centrifuge can either be restarted and the test element replaced to conclude testing or if sufficient predictive information is obtained, at least one new test element can be added to the centrifuge.
According to another aspect, there is disclosed a method for performing immunodiagnostic testing, said method including the steps of: adding patient sample to a test element for purposes of creating an agglutination reaction that can be graded, said test element including at least one column retaining an inert test material, a reagent, and a quantity of said patient sample wherein the test element is capable of producing an agglutination reaction; placing said test element within a centrifuge; centrifuging said test element to accelerate the agglutination reaction; and imaging said test element prior to the completion of a full centrifugation cycle to obtain predictive test data.
The method further includes the steps of predicting the grade of a agglutination reaction formed within the test element prior to the termination of the centrifugation cycle and terminating the centrifuging step based on predictive data obtained. According to this method, either single and/or multiple in-situ images can be obtained in which the imaging step can be performed dynamically while the centrifuge is still operating or statically at an intermediate point in the test cycle with the test element either in the centrifuge or separately removed for evaluation.
According to another version, there is described an immunodiagnostic testing apparatus comprising a centrifuge, at least one imager disposed in proximity to said centrifuge such that at least one image can be captured of at least one test element that is capable of producing a perceivable agglutination reaction that can be graded. The at least one imager is disposed to capture said at least one image while said at least one test element is in the centrifuge and in which said at least one captured image is captured prior to the conclusion of a predetermined centrifugation time period.
One advantage realized using the apparatus and methods as described herein is that it is possible to extract more data concerning aspects of an immunodiagnostic test and also determine an earlier result than with currently known testing apparatus. It is also advantageous in that failure modes can also be identified at an earlier point in the process, thereby providing significant time savings and providing additional scheduling opportunities.
In addition, providing in-situ imaging of the test elements provides drastic improvements to time management using testing apparatus in that immunodiagnostic test elements no longer require a separate operation to transport them into a reader queue, thereby simplifying and optimizing the design and footprint of such apparatus, while also significantly improving throughput.
These and other features and advantages will become readily apparent from the following Detailed Description, which should be read in conjunction with the accompanying drawings.
The following relates to apparatus and related methods for immunodiagnostic testing of at least one exemplary test element, in this example, a “gel card” or “bead cassette”. It will be readily apparent that other forms of apparatus as well as other forms of test elements, such as, microplates and the like can be incorporated that apply the same inventive aspects. In addition and in order to provide a suitable frame of reference with regard to the accompanying drawings, certain terms are used throughout. It is not intended that these terms are limiting of the scope of the inventive concepts described herein, except in instances where so specifically indicated.
Referring to
More particularly, the sample and reagent holding supply 115 according to this specific apparatus 100 includes a plurality of patient vials that are disposed in a sample rack 116, as well as reagents that are separately disposed within vials maintained within a reagent rack 120. A bar code reader 119 is also provided to identify the sample being tested wherein the vials include labels (not shown) with encoded symbology such as the lot number, expiration date and other pertinent information. A drive mechanism 135, shown in
More detailed information relating to each of the above referred to assemblies, as well as the automated testing apparatus 100 in general, can be found in commonly-assigned U.S. Pat. No. 5,578,269 to Yaremko et al., the entire contents of which were incorporated by reference previously.
Before describing the operation of the apparatus 100 and referring to
Referring to
In terms of processing, a typical centrifugation cycle may extend for 10-20 minutes or more, depending on the nature of the specific test that is being performed by the apparatus. In order to evaluate the resulting reaction, if any, the test elements 60 are then removed from the centrifuge 118 of the testing apparatus 100 by means of the gripper 171 and the test element is transferred to the storage rack 151 of the analysis station 124. This rack 151 then rotates in order to position the test element 60 immediately adjacent the test element holder 143. The transport subsystem 149 of the analysis station 124 subsequently transfers the test element 60 from the storage rack 151 to the element holder 143 and a digitized image of the test element, or pertinent portions thereof, is obtained using the imaging subsystem 147 in combination with the illumination assembly 145. The digitized data of the test element 60 is then utilized by the connected processing subsystem 148 in order to determine if a reaction has occurred in the test element and if so, the classification of the reaction. This determination can be also be made based on the images using machine vision.
An exemplary test element 60 is shown in
With the foregoing serving as background and referring to
The centrifuge chamber or module 222 of the herein described apparatus is defined by a housing (not shown) that retains a centrifuge 224. The centrifuge 224 according to this embodiment includes a rotatable arm member 228 having a pair of opposing ends 232, 236 that extend radially outward from a center hub 240. Each of the ends 232, 236 of the rotatable arm member 228 are configured to support at least one test element 60 thereupon, such as the exemplary element described above with regard to FIG. 3. According to the present embodiment, a test element 60 is supported by a clamp at each arm end 232, 236 with the top end 66,
Referring to
According to a preferred version, an imaging assembly 250 is disposed within the centrifuge chamber 222 of testing apparatus 220 is preferably mounted in a fixed location within the housing such that the ends 232, 236 of the rotatable arm member 228 of the centrifuge 224 pass in relation thereto. It should be noted in passing that alternative mounting schemes can be provided. For example, a bucket-type centrifuge can be provided in which a portion of the centrifuge supporting the at least one test element can pivot outwardly away from a center hub under the influence of centrifugal force. In this instance, the imaging assembly can be alternatively positioned so as to access the at least one test element from above. Other similar configurations are possible.
The imaging assembly 250 according to this embodiment includes at least one electronic imager, such as a CCD or CMOS-type imager having an array of pixels that are disposed within a housing 260 having an opening 264 that permits an image of the rotatable arm member 228, and in particular a retained test element 60, to be captured. Alternatively, other imaging means, such as a conventional camera, can be utilized. An illumination assembly 272 is disposed in relation to the imaging assembly 250 and includes a light source such as a strobe lamp, at least one LED, incandescent lamp, or other suitable source capable of emitting light. The illumination assembly can be separately disposed in relation to the imager assembly 250 or can be integrated directly therein, such as a flash assembly of a conventional 35 mm camera, by way of example.
Referring to
In an alternative version and rather than using the imager “on the fly”, the centrifuge 222 can be stopped at an intermediate point in the cycle and the imaging assembly 250 can be used to capture at least one image of the test element 60, and particularly that of the transparent microtubes 68. Alternatively, the centrifuge 222 can be stopped and the at least one supported test element 60 can be removed by means of a gripper or other means using a transfer assembly of the apparatus or otherwise at a predetermined intermediate point in the centrifugation time cycle prior to completion. The test element(s) can then be transferred to the analysis station of the testing apparatus, such as that previously described with regard to
Referring to
Essential to the teachings described herein and in either instance; that is, whether the imager assembly is located within the centrifuge for activation of the imaging assembly 250 or an image is captured statically within or in another part of the testing apparatus, the at least one image is captured at an intermediate point in the centrifugation cycle, but prior to conclusion thereof. If the results indicate that a predictive grade of the reaction (for example, no reaction or strong reaction) can be made or that a failure mode exists then, according to step 314, the controller 280 either causes the motor 244 to stop the centrifuge 222 in advance of the completion of the centrifugation cycle and the test element 60 is removed in the case of an embedded imager or the test element is not placed back into the centrifuge in the instance in which a test element is first removed prior to capturing the at least one image. If a predictive grade cannot be made or if a failure mode cannot be identified, then centrifugation proceeds, step 316, wherein another image, steps 320, 322 may be taken in advance of completion of the cycle time and the foregoing steps are repeated. In one version, multiple images can be taken intermediately in the centrifugation cycle so as to determine the rate of change of the reaction (i.e., movement of agglutinates in distance as measured over time), if any, and of process endpoint, for example by means of a velocity vector of the agglutinates through the inert matrix of the column as determined algorithmically based on the captured images. In the instance in which the at least one image is taken outside of the centrifuge, the test element is routed back to the centrifuge by the transport assembly of the apparatus and the centrifugation cycle resumes.
It will be readily apparent that there are numerous variations and modifications that can be made within the intended scope of the invention, as defined by the following claims.
