Patent Publication Number: US-2007116593-A1

Title: Occult blood testing apparatus with features for enhancing ease of use

Description:
RELATED APPLICATION  
      This is a divisional of U.S. patent application Ser. No. 10/139,473 filed on May 3, 2002, the entire disclosure of which is incorporated herein. 
    
    
     BACKGROUND OF THE INVENTION  
      The present invention is directed to systems and methods useful in testing for occult blood in a fecal specimen. More particularly, the invention is directed to a testing apparatus which is suitable for at-home use by untrained individuals, as well as by clinicians in hospitals and doctor offices.  
      Over 140,000 new persons per year in the United States are afflicted with cancer of the colon and rectum, the disease occurring equally in both men and women. Contrary to many other forms of cancer, early diagnosis and treatment of colorectal cancer and its precursor polyps does result in a cure rate of 80% to 90%. If, however, the disease is not detected until the later stages, the cure rate drops significantly. Thus, early detection of the disease is important to successful treatment of colorectal cancer. For this reason, it is recommended that all individuals over age 50 with no family history of the disease be screened annually for colorectal cancers. Individuals with family history of the disease or other known risk factors should be screened annually beginning no later than age 40.  
      Conventional screening procedures consist of testing for occult (hidden) blood in stool samples provided by a patient. Typically, the patient must collect two separate specimens on a test card on each of three consecutive days, and then deliver the test cards to a laboratory. At the laboratory, a physician or lab technician applies developer liquid to each specimen&#39;s test matrix, which has previously been impregnated with a suitable chromogenic reagent, such as guaiac. If blood is present in the specimen, the chromogenic reagent will cause the test matrix to change colors when the developer fluid is added, indicating that fecal occult blood or a similar reactant has been found.  
      One factor deterring individuals from undergoing their recommended annual screening is the natural revulsion which many, if not most, people feel toward handling and looking at fecal matter. This revulsion may be amplified by the lack of a suitable implement for obtaining a specimen and applying it to the test matrix. Most test kits simply provide a wooden coffee-stirrer type stick which is somewhat difficult to manipulate and often, because of its generally smooth exterior surface, does not pick up a large enough sample or retain the sample without risk of dropping some of the fecal matter. Another unpleasant factor is the inconvenience and, sometimes, embarrassment associated with transporting or mailing the fecal matter specimens to a testing laboratory in a paper envelope.  
      In order to eliminate or reduce the aforementioned problems, various attempts have been made to develop a convenient test kit which requires a minimum of handling of fecal specimens, and can be performed by an untrained individual in the privacy of his or her own home. Examples of such attempts are disclosed in U.S. Pat. Nos. 4,582,685 and 5,196,167 to Guadagno et al., and U.S. Pat. No. 5,840,584 to Waldenburg. None of these prior art test kits have successfully met all of the needs of in-home users, however, and none has been approved by the FDA for over-the-counter sale.  
      To date, the only fecal occult blood testing kit which has been approved by for the FDA for over-the-counter sale is a kit manufactured by Diagnostica, Inc., of Las Vegas, Nev., features of which are disclosed in U.S. patent application Ser. No. 09/132,439 and International Application No. PCT/US99/17954. The Diagnostica kit comprises a container of free-standing developing medium, and a test matrix having a specimen placement area on one side. On the opposite side of the test matrix is a result area that generally coincides with the specimen placement area, and a control area that is longitudinally spaced from the result area. Both the container and the matrix are encased in a housing having a first pair of openings aligned with the specimen placement area, a second pair of openings aligned with the result area, and a third pair of openings aligned with the control area. A cover is provided for securely enclosing a specimen located on the specimen placement area. To test for occult blood, a user simply places fecal specimens in the openings aligned with the specimen placement area, closes the cover, compresses the housing to break the container and releases the developing medium. He or she then turns the housing over to look for appropriate color changes in the result and control areas.  
      The aforementioned Diagnostica test kit possesses numerous advantages over the prior art. The cover is particularly advantageous, since it keeps the fecal specimen out of the user&#39;s sight and prevents it from dropping off of leaking from the specimen placement area, even when the user inverts the housing to read the results. In addition, the kit can be disposed of easily and hygienically after testing, with no need for special handling.  
      Nonetheless, the Diagnostica kit disclosed in the aforementioned U.S. and International patent applications has some potential drawbacks. Users who have not performed the test before may have difficulty understanding or remembering the instructions and may perform the steps in the wrong order. In addition, some users may collect too little or too much sample on the stick provided with the kit, and have difficulty spreading it over the specimen placement area. Still others may find it difficult to open and close the cover of the housing with one hand while holding the specimen collection stick in the other hand.  
      Accordingly, it would be advantageous to provide an apparatus for testing for occult blood, for example, fecal occult blood, with features that enhance its ease of use by untrained individuals. Further, it would be advantageous to provide a hygienic and relatively simple test kit which reduces the need for manual dexterity, while providing accurate and reliable results.  
     SUMMARY OF THE INVENTION  
      A self-contained system for testing for the presence of occult blood in a specimen has been provided with features enhancing its ease of use. The system includes a housing holding a test matrix and a container for releasing a developing medium onto the test matrix. The housing includes a base portion encasing both the container and the test matrix, and a moveable cover for selectively covering and uncovering the base. The cover is provided with a tab which can be manipulated with a finger of one hand, and the base is provided with tabs which can be grasped easily with one or two other fingers of the same hand, thus allowing the cover to be easily opened and closed with one hand.  
      An applicator provided for use with the system includes a handle portion configured to be grasped by a user and a distal portion having an end configured for optimized retrieval and spreading of the specimen on the test matrix. In a preferred embodiment, the applicator comprises two identical applicator halves, one of which serves as the handle portion and the other of which serves as the distal portion. Connector elements are provided for joining the two halves together. For reasons of manufacturing convenience, the two halves are integrally formed with and frangibly connected to opposite sides of the system housing. To use the applicator, a user simply detaches the two applicator halves from the housing, assembles them end-to-end, then collects and applies the specimen as instructed.  
      The instructions for use are preferably embossed or otherwise printed on the various components of the system. These instructions preferably indicate both the order in which the steps of the testing procedure are to be performed, and the location for carrying out the steps. Thus, steps to be performed with the cover closed are provided on the cover, steps to be performed with the cover open are provided on the top portion of the base, and steps to be performed with the housing inverted (and the cover closed) are provided on the bottom portion of the base. This reduces the chance of any confusion on the part of the user, and increases the likelihood that the test will be performed correctly and accurate results obtained.  
      Each and every feature and combination of two or more features described herein is included within the scope of the present invention provided that the features included in the combination are not mutually inconsistent.  
      These and other aspects and advantages of the present invention are set forth in the following detailed description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a system for testing for fecal occult blood in accordance with the present invention, with a portion broken away to show interior detail;  
       FIG. 2  is a plan view of the housing, cover, and applicator of the system before assembly;  
       FIG. 2A  is an enlarged end view of the bottom section of the housing before assembly;  
       FIG. 3  is a plan view of the system after assembly;  
       FIG. 4  is an enlarged fragmentary perspective view showing a portion of the base of the system housing, with a portion broken away to show interior detail;  
       FIG. 5  is a perspective view of an applicator assembly in accordance with the present invention;  
       FIG. 6  is an enlarged plan view of the encircled area  6 - 6  of  FIG. 5 ;  
       FIG. 7  is a plan view of the encircled area  7 - 7  of  FIG. 5 ;  
       FIG. 8  is an enlarged, fragmentary view of a section taken through line  8 - 8  of  FIG. 1 ;  
       FIG. 9  is an enlarged end view of  FIG. 7 ;  
       FIG. 10  is a top plan view of the housing of the system according to a preferred embodiment, with the cover in a closed position;  
       FIG. 11  is a perspective view of the housing according to the embodiment shown in  FIG. 10 , with the cover in an open position; and  
       FIG. 12  is a bottom plan view of the housing according to the embodiment of  FIG. 10 . 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
      Referring now to the drawings,  FIG. 1  shows a self-contained system  10  for testing for a reactant such as occult blood in a specimen of a spreadable substance such as fecal matter (not shown). The system comprises a housing  12  enclosing a test matrix  14  such as guaiac-treated paper (shown in  FIG. 4 ), and a glass ampule  16  filled with a free-standing liquid developing medium such as liquid hydrogen peroxide/ethyl alcohol solution. An applicator  18  is provided for collecting the fecal matter specimen and applying it to a specimen placement area  20  on the test matrix  14 .  
      Referring now to  FIG. 2 , the unassembled housing, which is preferably provided to the consumer in a hermetically sealed foil pouch (not shown), includes a base  22  and a cover  24 . The base  22  has a bottom section  26  and a top section  28 . Identical applicator halves  30  and  32  are coupled to opposite sides of the top section  28  of the base  22 . In a preferred embodiment of the invention, the cover  24 , bottom section  26 , top section  28 , and applicator halves  30 ,  32  are made from a unitary or single piece of plastic or polymer material. The cover  24 , bottom base section  26 , and top base section  28  are preferably flexibly and serially joined to one another by thinned hinge elements  34  and  36 , while the applicator halves  30 ,  32  are frangibly connected to the top section  28  of the base  22  by weakened elements  38 ,  39 ,  40 , and  41 . Other embodiments of the invention may provide the applicator separately from the housing, for example, and/or in a single piece, as a pair of non-identical pieces or more than two pieces. Similarly, the cover and the sections of the base could be made of more than one piece, made of materials other than plastic, and/or have sections of other shapes.  
       FIG. 3  shows the system  10  in the form in which it is provided to the user. The test matrix and ampule have been placed underneath the top section  28  of the base  22 , and the bottom section  26  has been folded up against the top section  28 , locking the test matrix and ampule into position. The cover  24  has been latched over the specimen placement openings to prevent contamination of the test matrix during transport. The only portion of the system  10  which has not been preassembled is the applicator  18 .  
      Returning now to  FIG. 2  with additional reference to  FIG. 12 , the bottom section  26  of the base  22  has two oblong openings  42 ,  44  near a first end  46 . The oblong openings have beveled edges  48  for better viewing of the validation areas  50  of the test matrix  14 . Two rectangular openings  52 ,  54  are provided near a second end  56  of the bottom section  26 . The rectangular openings  52 ,  54  have beveled edges  58  for better viewing of the result areas  60  of the test matrix  14 . A circular depression  62  is located in the second surface  51  intermediate the validation area viewing openings  42 ,  44  and the result area viewing openings  52 ,  54 . A protuberance  64  is located in the center of the depression  62 . The depression  62  decreases the rigidity of the bottom section  26  and enables a user to compress the ampule when the protuberance  64  is pressed against a hard, flat surface such as a table or counter top.  
      It has been found that a depression  62  formed in the second surface  51  of the bottom section  26  reduces the amount of liquid needed to saturate the matrix relative to the amount that would be needed if the depression were formed in the first surface  49 .  
       FIG. 2A  is an enlarged end view showing that the bottom section  26  of the base is slightly curved about a vertical axis of symmetry y. Specifically, the bottom section  26  has generally flat side edge portions  43 ,  45 , and a central portion  47  including a first surface  49  and a second surface  51 , both of which are somewhat concave with respect to the illustrated horizontal axis x. When the bottom section  26  is folded about the front hinge  36  and snapped into place underneath the top section  28 , the curvature is flattened with respect to the horizontal axis x. Thus, the first surface  49  is urged against the center of the top section, compressing the test matrix and holding it securely in place. This minimizes the amount of open space between the top and bottom sections  26  and  28 , which in turn further minimizes the amount of liquid needed to saturate the matrix in a given short period of time.  
      The top section  28  of the base  22 , best shown in  FIG. 11 , includes two rectangular openings  66 ,  68  that align with specimen placement areas  70  on the text matrix  14 , on the opposite side from the result areas  60  and result viewing openings  52 ,  54 . An oblong ampule-holding dome  74  extends between the specimen placement openings  66 ,  68  and the end of the top section  28  near the rear hinge  34 . Extending from the inner top wall of the dome  74  are two projections (not shown) which act in tandem with the depression  62  and protuberance  64  on the bottom section  26  to facilitate breaking of the ampule  16 .  
      The front hinge  36  projects distally along the front of the section  28  and matingly receives a hook  75  depending from the underside of the cover  24  to latch the cover when necessary. A gripping arrangement comprising tabs  77 ,  79  and  81  (seen in  FIG. 10 ) is provided for allowing a user to easily open and close the cover  24  with one hand while holding an applicator in the other hand. Specifically, the tabs  77 ,  79 , which extend distally and laterally from the corners of the top section  28  on either side of the hinge  36 , are structured for a user to hold between two fingers, for instance the thumb and middle finger, of one hand while pressing upwardly with another finger, for instance the index finger, of the same hand against the tab  81  extending distally from the front edge of the cover  24 . Strictly speaking, only one tab  77  or  79  is required on the top section  28  of the base, since most users will be able to open the cover  24  using only the thumb and finger of one hand. However, two tabs  77 ,  79  are preferred, since such an arrangement is equally convenient for both right and left-handed users, and also for users with decreased manual dexterity or strength.  
      Referring again to  FIG. 3 , with additional reference to  FIGS. 5 and 6 , each of the applicator halves  30 ,  32  comprises a relatively narrow distal end  76   a,b  and a wider, hollow proximal end  78   a,b . To assemble the applicator  10 , the user simply detaches the two applicator halves  30 ,  32  from the sides of the base  28 , and inserts the distal end  76   b  of one applicator half  32  into the hollow proximal end  78   a  of the other applicator half  30 . A close fit between the distal end  76   b  of one applicator half  32  and the receiving proximal end  78   a  of the other applicator half  30  ensures that the halves  30 ,  32  will be securely joined.  
      When the applicator halves  30 ,  32  are assembled, the proximally positioned half  32  serves as a handle to be grasped by the user, while the distal end  76   a  of the distally positioned half  30  serves as a collector and spreader.  
      Referring now to  FIGS. 7-9 , the spreader or distal end  76   a  of the applicator  18  includes a generally planar front surface  80 , a generally planar rear surface (not shown) and a pair of side walls  82 ,  84 . The front and rear surfaces are recessed with respect to the side walls  82 ,  84 , and intersect to form a shoulder  86  that curves about a center of curvature x′ to define a first radius of curvature R. A spreading tip  88  extends distally of the shoulder  86 .  
      The features of the spreading tip  88  can best be appreciated after considering the design of the specimen placement openings, as shown in detail in  FIGS. 4 and 8 . Specifically, the specimen placement openings  66 ,  68  have beveled, generally trapezoidal walls  72  that assist in positioning specimens on the specimen placement area  70  and define a recess with enough volume to receive and hold a fecal sample when the cover  24  is closed. Each recess has a width w equal to the width of the specimen placement area and a depth d equal to the height of the beveled walls  72 . The spreading tip  88  includes a pair of side edges  92 ,  93  which are preferably conical and have a cone angle conforming to the beveled side walls  72  of the specimen placement openings  66 ,  68 . In the most preferred embodiment of the invention, the width w of the distal surface  90  is substantially equal to the width w of the specimen placement openings  66 ,  68 , and the length L of the spreading tip  88  is slightly less than the depth d of the specimen placement openings  66 ,  68 . This close fit between the tip  88  and the specimen placement openings  66 ,  68  helps ensure that the applicator tip spreads the specimen evenly and thinly over the specimen placement area.  
      In addition, the spreading tip has a curved distal surface  90  that extends between the side edges  92 ,  93 . The distal surface  90  defines a second radius of curvature r=R+L about the center of curvature x′. Because the spreading tip  88  and the end portion  85  of the applicator have the same center of curvature x′, a user is able to maintain a constant distance from the center x′ to the test matrix while applying the samples, regardless of moderate changes of the angle at which the applicator  18  is tilted with respect to the test matrix. This results in a constant clearance c between the distal surface  90  of the applicator and the test matrix  14 , allowing the user to easily apply the specimen in a layer of fairly uniform thickness.  
      The distal and proximal surfaces  90 ,  91  of the spreading tip  88  are preferably textured or otherwise enhanced to increase the amount of fecal matter collected by the applicator  18  and minimize the likelihood of any fecal matter falling off. In the illustrated embodiment, best seen in  FIG. 9 , the textured surface  90  comprises a multitude of small bumps yielding a sandpaper-like finish. Other surface features, such as grooves, fins, dimples or the like, that increase the effective surface area and holding power of the tip can also be used. Alternatively, the retentiveness of the surface could be enhanced with coatings having adhesive properties or an affinity for fecal matter.  
       FIGS. 10-12  show an especially preferred embodiment of the invention, wherein the various components of the housing  12  include indicia leading the user through the steps of a testing procedure. The indicia are preferably provided in sets, with each set of indicia designating both the order in which a particular step is to be performed, and the place for performing it. For instance, a first set of indicia  94  provided near the distal end of the cover  24  of the housing  12  may point toward the tab  81  and instruct the user to “ LIFT FIRST .” Upon lifting the cover, the user may find a second set of indicia  95  near the specimen placement openings  66 ,  68 , instructing him or her to (apply the) “ SAMPLES  2 nd .” A third set of indicia  96  located on the cover  24  on an upper dome  97  above the ampule-holding dome  74  may instruct the user to “ PRESS  3 rd ”, thus breaking the capsule and releasing the developing medium onto the test matrix. A fourth set of indicia  98  on the bottom section  26  of the housing base  22  identifies the location of the “ CONTROLS ” and “ RESULTS ” and instructs the user that these are to be viewed “4 th .” 
      For optimum readability, it is preferred that the indicia be embossed on the housing. However, imprinted stickers or other less permanent forms of indicia may be preferable in some instances, especially in overseas markets where many languages will be required. Additional indicia could be provided for designating where to snap the applicator halves off the housing, indicating which end of the applicator is the sample end, warning the user not to open the base because of glass inside, and so forth. Of course, the exact wording of any of the instructions is not critical, and may be varied according to consumer needs.  
      The indicia may also provide information such as a website, mailing address, or phone number which the user may contact if he or she has questions about the procedure or results. If the results are positive or indeterminate, the user may wish to save another undeveloped test kit to show to a physician. Ideally, if the results are clearly negative, the user simply reinserts the kit and applicator halves into the foil pouch in which they were provided, folds over the top of the pouch, and throws it away. No further special handling or sanitary precautions are needed since the fecal matter is entirely enclosed.  
      While this invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims. For instance, the ease of use features disclosed can successfully be used with fecal blood testing kits employing polyclonal or monoclonal antibody systems, or any other alternatives to the guaiac-based chemistry system disclosed in International Patent Application No. PCT/US99/17594. The features may also be used in both chemical and non-chemical systems for revealing the presence of a wider variety of anomalous substances other than blood, such as parasites, for instance, in feces or other spreadable specimens.