Abstract:
A system for automatically testing a fluid specimen to indicate the presence of specified chemical components in the specimen. The system utilizes an assaying device having a collection cup and a cap that carries at least one test strip. The device includes an integrated aliquot delivery mechanism actuatable to wet the test strip with an aliquot delivered from the fluid specimen. The assaying device operates in conjunction with an electronic reader device capable of actuating the aliquot delivery mechanism and reading the reaction of the test strip. A reader device defines a keyed receptacle for accommodating a complementary shaped cup housing in a particular orientation. The reader device includes a camera for capturing the image of a test strip, an actuator for actuating an aliquot delivery mechanism, and a microprocessor/controller for (1) controlling the camera and actuator and (2) processing the image.

Description:
RELATED APPLICATIONS 
     This application is a continuation and claims priority benefit with regard to all common subject matter, of U.S. application Ser. No. 13/100,393, filed May 4, 2011; which is a continuation of U.S. application Ser. No. 11/553,836, filed Oct. 27, 2006, now U.S. Pat. No. 7,943,381, issued May 17, 2011; which is a continuation of U.S. application Ser. No. 10/954,823, filed Sep. 30, 2004, now U.S. Pat. No. 7,537,733, issued May 26, 2009; which is a division of U.S. application Ser. No. 10/779,014, filed Feb. 13, 2004, now U.S. Pat. No. 6,964,752, issued Nov. 15, 2005; which is division of U.S. Application Ser. No. 10/072,154, filed Feb. 6, 2002, now U.S. Pat. No. 6,716,393, issued Apr. 6, 2004; which is a continuation-in-part of U.S. application Ser. No. 09/444,926, filed Nov. 24, 1999, now U.S. Pat. No. 6,514,461, issued Feb. 4, 2003; which is a continuation-in-part of U.S. application Ser. No. 09/245,175, filed Feb. 5, 1999, now U.S. Pat. No. 6,342,183, issued Jan. 29, 2002. U.S. application Ser. No. 11/063,408, filed Feb. 23, 2005; U.S. application Ser. No. 08/832,957, filed Apr. 4, 1997, now U.S. Pat. No. 5,929,422, issued Jul. 27, 1999; U.S. application Ser. No. 08/801,041, filed Feb. 14, 1997, now U.S. Pat. No. 5,916,815, issued Jun. 29, 1999; U.S. application Ser. No. 09/018,487, filed Feb. 4, 1998, now U.S. Pat. No. 6,036,092, issued Mar. 14, 2000; and U.S. application Ser. No. 09/025,559, filed Feb. 18, 1998, now U.S. Pat. No. 5,902,982, issued May 11, 1999, are also related. The disclosures of the aforementioned applications/patents are herein incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to systems for automatically testing fluid specimens, e.g. urine or other body fluids, to detect chemical substances or components therein. Such systems can be used, for example, to screen employee applicants for illegal drug use. 
     Employee drug testing typically involves an initial screening test to identify specimens which are negative (i.e., no drugs present). This test is usually performed with a low cost immunoassay which is very sensitive to small quantities of drug metabolites. If a drug metabolite is detected (referred to as “presumptive positive”), the specimen is then subjected to a confirmation test which typically utilizes a highly specific test method, such as a gas chromatography/mass spectrometry (GC/MS), to identify the specific drug components in the specimen. 
     Traditionally, both the screening and confirmation tests were performed in a common facility, i.e., centralized laboratory. More recently, systems have been implemented which perform the screening test at a local service site. They typically employ drug test kits which follow the tradition of home pregnancy test kits, i.e., they detect the presence of a specific drug substance(s) in a urine specimen. Such drug test kits generally identify, in human readable form, the drug(s) being tested to indicate the presence (or absence) of that drug. The screening test result with respect to each particular drug, and to the specimen as a whole, can either be (1) negative or (2) presumptively positive. If presumptively positive, then the specimen is generally sent to a remote laboratory for confirmation testing. 
     Inasmuch as disclosure of a presumptive positive test result can adversely impact an applicant&#39;s record and could potentially lead to litigation and employer liability, it is extremely important to prevent the inadvertent dissemination of test result data. 
     The aforementioned parent U.S. Pat. No. 6,342,183 describes an apparatus for locally analyzing a specimen to qualitatively detect specified chemical components therein. The apparatus includes an assaying device comprised of a cup for collecting a fluid specimen and a cap carrying at least one test strip for visually reacting to one or more specified chemical components in the specimen. The assaying device is preferably configured to interact with a reader device capable of reading the reaction of the test strip to produce an electronic data output. 
     More particularly, the apparatus described in application Ser. No. 09/245,175 includes an open cup defining an interior volume for accommodating a fluid specimen and an attachable cap configured for mounting on the cup to seal the interior volume. The cap carries at least one test strip and an integrated aliquot delivery mechanism actuatable to wet the test strip with an aliquot derived from the fluid specimen. The aliquot delivery mechanism preferably comprises a pump in the form of a plunger for forcing an aliquot of the fluid specimen onto the test strip. The plunger can be actuated either manually or automatically, e.g., by a piston controlled by a compatible reader device. The reader device preferably includes a microprocessor based controller for actuating the aliquot delivery mechanism, a camera for producing an image of the test strip, and a processor for analyzing the image to produce test result data. The test result data, along with identification data read from a label carried by the cap, can then be stored or communicated, e.g., via a modem. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an improved system and components thereof for automatically testing a fluid specimen, e.g. urine, saliva, or other body fluids, to indicate for the presence of specified chemical components in the specimen. 
     A system in accordance with the invention preferably utilizes an assaying device comprised of a collection cup and a cap which carries at least one test strip. The device includes an integrated aliquot delivery mechanism actuatable to wet the test strip with an aliquot derived from the fluid specimen. The assaying device is configured to operate in conjunction with an electronic reader device capable of actuating the aliquot delivery mechanism and reading the reaction of the test strip. 
     A preferred reader device in accordance with the invention preferably defines a keyed receptacle for accommodating a complementary shaped cup housing in a particular orientation. The reader device is comprised of a camera for capturing the image of a test strip, an actuator for actuating an aliquot delivery mechanism, and a microprocessor/controller for (1) controlling the camera and actuator and (2) processing the image. 
     In a preferred embodiment of the invention, the reader device preferably also includes a network connectivity device, e.g. modem, for enabling communication with a remote host computer. Although each reader device can operate independently as a stand-alone device, a preferred system in accordance with the inventor employs a host computer or server, which communicates, via a public and/or private network, with a plurality of reader devices located at separate service sites. Each service site can be configured to operate as a “thin client” with primary control being exercised by the host computer via the network. Alternatively, primary control can be exercised by the reader device at each site with only high level supervisory control coming from the host computer. 
     A preferred assaying device in accordance with the invention includes a cap carrying multiple test strips including at least one component test strip and at least one adulteration test strip. The cap is either formed of transparent material or is provided with transparent windows to permit external viewing of the test strips by the reader device camera. The cap preferably also carries one or more fiducial marks to facilitate image processing. Further, the cap preferably also carries machine readable identification information, e.g., a bar code label, to positively associate the specimen and test results with the correct individual. Preferably, the cap does not bear any human readable indicia identifying the specimen donor or indicating test results. 
     A preferred test strip for testing for the presence of specific chemical components is configured with multiple latent lines (i.e., markings) which can become visible when the strip is wetted. The lines preferably include a control or reference line and multiple drug lines each related to a different chemical component. If all of the latent lines visually appear within a certain test interval, e.g., up to eight minutes, after the strip has been wetted, this will indicate the absence of the specific chemical components sought. However, if any of those specific chemical components are present in concentrations above a certain threshold, their presence will suppress the appearance of one or more of the drug lines to indicate the presence of such chemical components. 
     A preferred reader device in accordance with the invention includes a camera located so that the cap is imaged onto the camera focal plane. The reader device includes a piston motor for driving a piston against the assaying device to deliver an aliquot to the test strips. The piston motor also moves a light shield into place around the cap enabling a light source to illuminate the cap to enhance the image for the camera. 
     A preferred automatic testing system in accordance with the invention operates as follows:
         1. Fluid deposited into cup at local site; secure cap in tamper evident fashion;   2. Site administrator places assaying device, i.e., cup and cap, into “keyed” receptacle of local reader and enters ID information;   3. Reader alerts host computer via communication network;   4. Initiate automatic reader operational sequence:
           a. capture cap image and verify acceptability to proceed   b. run piston motor to advance piston into assaying device to force fluid up channels to wet component and adulteration test strips   c. capture cap image and verify acceptability to proceed   d. periodically capture additional cap images during development interval up to about eight minutes   e. analyze captured image data to determine
               1. test validity   2. test results   
               f. locally display test validity/results and/or communicate test validity/results to Host computer   g. run piston motor to withdraw piston from cup   
           5. Site administrator removes cup from reader       

     The camera produces a digital representation of the image incident on the camera focal plane. The processor then analyzes the digital representation to determine the color of the adulteration test strip and to locate visible markings on the component test strip coincident with the reference and drug lines. Image analysis is preferably performed by initially using fiducial marks on the cap to first precisely locate the cap image relative to a reference image. This can, for example, involve rotating, translating, and/or scaling the cap image. Thereafter, the digital representation of each test strip is examined to determine the presence (or absence) of drug lines. This involves first locating the strip reference line by effectively “drawing” a rectangular region around the reference line. The region can be considered as a rectangular matrix of pixels having rows extending across the strip width, each row being comprised of multiple column positions. For each row, the image is examined to determine whether the pixel at each column position exceeds a threshold. The sum of pixels exceeding the threshold is determined for each row. These row sums produce a graph whose x axis is related to the height (i.e., number of rows) of the region and whose y axis is related to the values of the individual row sums. A bell shaped curve will result whose peak locates the reference line. If no reference line is located, the test is terminated. If the reference line is located, then the examination continues in order to locate the drug lines. The detection of drug lines is more difficult because the amplitude, i.e., dark or light, of its pixels can vary widely dependent on several factors including wetting uniformity, urine color, variations amongst test strips, exposure time, etc. In order to compensate for these variations, each drug region is preferably divided into left, center, and right portions. A drug line is presumed to occupy the center portion of each region. However, its exact position and exact width can vary attributable to the aforementioned factors. Moreover, its brightness difference in relation to neighboring areas can be very subtle. Hence, a procedure is used to determine the weight of a line on a relative basis. 
     For example, for each drug region graph, the total area under each of three regions (left, center, right) is calculated. The left and right region areas are then numerically summed, and this resulting total area sum is multiplied by an experimentally determined “weighting value,” thus producing a weighted sum. If the area of the center region is less than or equal to the weighted sum, no line is present. By using urine samples with known drug concentrations, a weighting value of 0.75 has been experimentally determined to produce very acceptable results. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a block diagram of a system in accordance with the invention; 
         FIG. 2  is an isometric view of a preferred reader device in accordance with the present invention; 
         FIG. 3  is an isometric view of a preferred cup and cap; 
         FIG. 4  is a plan view of the cap top surface; 
         FIG. 5  is a front sectional view taken substantially along plane  5 - 5  of  FIG. 2 ; 
         FIG. 6  is a top sectional view taken substantially along plane  6 - 6  of  FIG. 5 ; 
         FIG. 7  is a side sectional view taken substantially along plane  7 - 7  of  FIG. 5  showing the piston in its non-actuated position; 
         FIG. 8  is a side sectional view similar to  FIG. 7  showing the piston in its actuated depressed position to force an aliquot to the cap for wetting the test strips; 
         FIG. 9A  is a sectional view taken substantially along the plane  9 A- 9 A of  FIG. 5  primarily showing the cup interior; 
         FIG. 9B  is an enlarged sectional view showing the aliquot delivery mechanism of  FIG. 9A  in greater detail; 
         FIG. 10A  is a diagrammatic view of a typical test strip used in embodiments of the present invention; 
         FIG. 10B  is a diagrammatic view of the test strip similar to  FIG. 10A  but modified to represent rectangular regions used to locate reference and drug lines; 
         FIGS. 10C and 10D  depict steps employed in analyzing a cap image to locate a strip reference line; and 
         FIGS. 10E and 10F  depict steps employed in analyzing a cap image to locate the presence of a strip drug line. 
     
    
    
     DETAILED DESCRIPTION 
     Attention is initially directed to  FIG. 1  which depicts a preferred system  20  in accordance with the invention comprised of multiple service sites  22  respectively identified as  1  through N. Each service site can operate independently as a stand-alone system to perform a screening test, as will be described hereinafter. However, in accordance with a preferred system configuration, the multiple service sites are connected to a network  24 , e.g., the Internet, for communication with a host computer  26 . 
     Each service site includes a reader device  28  configured to cooperate with an assaying device  30  comprised of a specimen collection cup  32  and a cap  34 .  FIG. 1  depicts a functional block diagram of the reader  28  whereas FIGS.  2  and  4 - 7  illustrate the reader&#39;s structural configuration. The structural configuration of the assaying device  30  is illustrated in  FIGS. 2-9 . 
     Briefly, the reader  28  is comprised of a processor/controller  36  programmed to operate (1) a camera  37  and light source  38  via a camera interface circuit  40  and (2) a piston motor  42  via a motor control circuit  44 . As will be discussed hereinafter, the piston motor  42  operates to deliver an aliquot from a specimen in the cup  32  to one or more test strips in the cap  34 . The test strips each produce a visible reaction in response to being wetted by the aliquot. The camera  37  and light source  38  operate together to capture an image of the test strip(s) enabling the processor/controller  36  to process the image to determine test validity and whether the specimen is free of chemical components being monitored. The reader  28  preferably operates in conjunction with an input/output device  46  which enables a site attendant to enter information, e.g., donor identification information, via a device such as a touch pad or keyboard, and to view information, e.g. via an LCD display, provided by the processor/controller  36 . 
     The processor/controller  36  is also preferably connected to the network  24  via a suitable connectivity device  48 , e.g., a modem. This enables the reader to upload data, e.g., test results, billing information, etc. to the host computer  26 . It also allows the host computer to exercise supervisory control over the processor/controller  36 . 
     Attention is now directed to  FIG. 2  which illustrates the exterior configuration of the reader housing  60 . The housing is essentially comprised of a base portion  62 , a head portion  64 , and an enclosure portion  66 , bridging the base and head portions. A receptacle  68  is defined between the base and head portions for receiving an assaying device  30  above a keyed recess  70  formed on base platform  72 . The keyed recess  70  is shaped complementary to the lower periphery of the assaying device  30  to place the device in a specific orientation relative to head portion  64 . The assaying device  30  is comprised of an open collection cup  32  and a detachable cap  34 . The cup  32  defines an interior volume for collecting a fluid specimen, e.g. urine. After the fluid specimen has been deposited into the cup  32 , the cap  34  is mounted thereon to seal the interior volume and prevent the fluid specimen from leaking. Inasmuch as each assaying device  30  is intended to be used only once to collect a single specimen, it is preferably fabricated via relatively low cost plastic molding processes. 
     It can be noted in  FIG. 3  that the cup  32  has an irregular lower periphery  76  particularly configured to mate with the keyed recess  70 . The periphery  76  includes an enlarged front portion  78  and a reduced rear portion  80 . The reduced rear portion  80  is bounded by flat finger grip sides  82  having raised surface features  84  extending to an oblique wall surface  86 . This irregular configuration of the cup facilitates easy manual handling of the cup enabling it to be readily grasped by the hand of a user and/or administrator. The cup enlarged portion  78  preferably includes an area  88  characterized by multiple vertical fins  90 . This area  88  functions as a key or registration area to which an index area  92  on the cap  34  is aligned to assure proper cap/cup sealing. Markings are preferably provided on the cup exterior to indicate maximum and minimum fill levels. 
     Briefly, the cap  34  is comprised of a substantially circular member  94  having a top exterior surface  96  and a depending flange or skirt  98 . The skirt  98  has a primarily knurled outer surface  100  that preferably defines flat areas  102  and the aforementioned index area  92 . The index area  92 , which may be defined by vertical slots, is preferably used to align with the aforementioned cup area  88  to visually indicate to a user that the cap has been properly installed onto the cup. The cap  34  is preferably installed onto the cup via a mating thread  104 . The cap  34  preferably carries a stop tooth  107  which rotates into engagement with the end fin  90  when the cap is properly installed onto the cup. When properly installed, the cap index area  92  will be aligned with the cup registration area  88 . Alternative mounting mechanisms, e.g., bayonet mount, can be used to couple the cap  34  to the cup  32 . 
     Provision is preferably made to include a tamper evident seal to immediately indicate to a user whether an assaying device, once sealed, has been tampered with. More particularly, note in  FIG. 3  that the cap top surface  96  carries a label  106  having a first portion  108  permanently adhered to the surface  96 . A second label portion  110  extends beyond the edge of cap  34  and is intended for sealing against cup area  111  immediately beneath the cup finned area  88 . The label portion  110  carries a suitable adhesive on its undersurface which, prior to use, is protected by release paper  112 . When the release paper is stripped away, label portion  110  can be sealed against cup area  111  to assure that cap  34  cannot be removed from cup  32  without that fact being immediately evident. The label  106  preferably also includes a perforated tear-off third portion  113  which can be affixed to a “B” container in case of split specimen collections, or in the event that a manual chain of custody record is required. 
     The cap top surface  96  ( FIG. 4 ) is either transparent or at least defines one or more transparent areas  114 , e.g., windows  114 A,  114 B, and  114 C for enabling a test strip mounted beneath each window to be visible therethrough. As will be discussed hereinafter, the cap defines one or more compartments each of which accommodates a test strip  115  which, when wetted by a fluid specimen, reacts to provide a visual indication indicative of a characteristic of the specimen. 
     In the exemplary embodiment illustrated, the window  114 C covers a test strip intended to detect specimen (1) authenticity and (2) adulteration. As is well known, a freshly voided urine specimen can be authenticated by a test strip which senses various characteristics including temperature and/or creatinine content of the specimen. Adulteration of the specimen can be detected by a test strip sensitive to exogenous components, e.g. pH and/or nitrites. Preferably, the test strip changes color when wetted and detection is achieved using a colormetric technique Larger windows  114 A and  114 B are intended to reveal test strips  115  for detecting various specific chemical components typically associated with illegal substance abuse.  FIG. 10A  schematically represents such a component test strip  116  showing multiple latent lines  117  visually represented on an indicator portion  118  extending from an absorbent portion  119 . The latent lines  117  typically include one or more reference or control lines  117 R and multiple drug lines  117 D 1 ,  117 D 2 , etc., each for a different drug or chemical component to be detected. If all of the lines visually appear within a certain test interval, e.g., up to eight minutes, after the absorbent portion  119  has been wetted, this will indicate the absence of the specific chemical components sought (i.e., a “negative” test). However, if any one of those specific chemical components is present in concentration above a certain threshold, its presence will suppress the appearance of one or more of the lines to indicate to an astute observer and/or computer based reader, the presence of that component. 
     The cap top surface  96  ( FIG. 4 ) preferably additionally defines a primary bar code area  120 , a secondary bar code area  121 , and one or more fiducial marks  122 , to be discussed hereinafter. All of the windows  114 , bar code areas, and fiducial marks are arranged around a plunger hole  124  within a tightly dimensioned image field  125  suitable for being imaged onto the focal plane of camera  37 . In an exemplary embodiment, the image field has width and height dimensions respectively equal to 1446 mils and 1084 mils which is imaged onto a camera view field having 640 pixels horizontally and 480 pixels vertically. 
     The internal structure and operation of a suitable assaying device  30  is described in aforementioned parent U.S. Pat. No. 6,342,183, whose disclosure is, by reference, incorporated herein. Briefly, as depicted in  FIGS. 5-9 , the assaying device cap  34  defines descending concentric outer and inner tubular walls  126  and  127 . Multiple passageways  128 A,  128 B,  128 C,  128 D extend vertically between the outer and inner tubular walls  126  and  127 . Each passageway  128  defines a passageway inlet  129  at the lower end of inner tubular wall  127  and a passageway outlet  130  proximate to compartments  131 , respectively accommodating component or adulteration test strips  132 , located beneath the aforementioned windows  114 . Overflow Basins  136 ,  138  are respectively located adjacent to the compartments beneath windows  114 A,  114 B to collect any fluid overflow. 
     The inner floor  150  of the cup  32  is configured to define an open well  152 . When the cap  34  is installed on the cup  32 , the lower end of the outer tubular wall  126  extends into the well  152  and essentially forms a closed chamber  154  for isolating a portion of the fluid specimen. A plunger  160 , comprised of a plunger pin  162  and plunger element  164 , is mounted in inner tubular wall  127  above chamber  154 . The plunger element  164 , is formed of soft conforming material able to seal against the inner surface of inner tubular wall  127 . The opening  124  in the cap top surface  96  provides access to enable the pin  162  to be depressed. 
     As the plunger element  164  is depressed into chamber  154 , the fluid therein is displaced upwardly via inlet  129  through multiple passageways  128 . These passageways,  128 A,  128 B,  128 C,  128 D respectively extend to the aforementioned test strip compartments located below the aforementioned cap windows  114 . Thus, depression of the plunger  160  within the inner tubular wall  127  displaces fluid from the chamber  154  to deliver an aliquot to each of the compartments  131 , each compartment accommodating a separate strip  115  of test material. The device  30  is constructed and dimensioned so that each aliquot comprises a specific volume of fluid. 
     Attention is now directed to  FIGS. 5-8  which illustrate the internal structure of the reader housing  60 . The housing  60  is formed by a base plate  150  having a vertical frame member  152  secured thereto. The base plate  151  is weighted by block  154  for stability. A shell  160  is affixed to the base plate  150  and frame member  152 . The shell includes a base platform member  72  which defines the aforementioned keyed recess  70 . The shell  160  additionally includes a rear shell member  162  which encloses a rear compartment  164  housing the reader electronic circuit board(s)  166 . An upper shell member  170  encloses a top compartment  172  which houses the camera  37 , light source  38  and piston motor  42 . These devices are structurally supported on arm  176  projecting forwardly from frame member  152 . 
     A piston subassembly  180  is mounted for vertical reciprocal motion toward and away from base plate  150 . The piston subassembly is comprised of a support arm  182  projecting forwardly from slide block  184  mounted for linear movement along guide rails  186 . The support arm  182  carries a piston member  186  aligned with opening  124  in the cap of an assaying device  30  placed in the keyed recess  70 . A lead screw  188  is threaded into hole  190  in support arm  182 . The lead screw can be selectively rotated either clockwise or counterclockwise by piston motor  42  to move the slide block  184  either up or down.  FIG. 7  depicts the piston member  186  in its up position providing sufficient clearance to allow an assaying device  30  to be placed on or removed from the keyed recess  70 .  FIG. 8  shows the piston member  186  in its down position extending into cap opening  124  to depress plunger  160  to displace fluid from the specimen in cup  32  to wet the test strips  115 . 
     It should also be noted that the piston subassembly  180  includes a substantially cylindrical light shield  192  mounted on slide block  184 . The light shield  192  defines a lower edge  194  which seals against the cap top surface  96  when the slide block is in its down position shown in  FIG. 8 . 
     The camera  37  can comprise a commercially available digital camera and appropriate optics for imaging the field  125  ( FIG. 4 ) onto the camera&#39;s focal plane. The camera preferably has a resolution of 640 (horizontal).times.480 (vertical) pixels. Imaging is enhanced by selective illumination of light sources  38  and by the shielding effect afforded by light shield  192 . 
     A preferred operational sequence for automatically testing a fluid specimen is represented by the following sequential steps:
         1. Donor at a local site deposits fluid into cup  32 ; site administrator enters identification information and secures cap  34  in tamper evident fashion;   2. Administrator places cup/cap into “keyed” receptacle  70  of local reader  28  and enters ID information;   3. Reader  28  alerts host computer  26  via communication network  24 ;   4. Host computer  26  (or administrator) initiates reader operational sequence:
           a. camera  37  captures cap image and processor  36  verifies acceptability to proceed   b. processor  36  runs piston motor  42  to advance piston  164  into cup to force fluid up channels  128  to wet component and adulteration test strips   c. camera captures additional cap image and verify acceptability to proceed   d. periodically capture additional cap images during development interval up to about eight minutes   e. processor analyzes captured image data to determine
               1. test validity   2. test results   
               f. processor  36  displays test validity/results on local I/O  46  and/or communicates test validity/results to Host computer  26     g. processor  36  runs piston motor to withdraw piston from cup   
           5. Site administrator removes cup from reader       

     In step 1, the site administrator first enters donor and client (e.g., employer) information via I/O devices  46  into a database stored either in processor  36  or host computer  26 . The donor voids into a cup  32  and the cap  34  is sealed thereon. The label is extended from the cap to the cup to assure that it is sealed in tamper evident fashion. Preferably the administrator and donor then initial the sealed label and review the chain of custody document. The donor and administrator both apply their signatures to the signature pad and a copy of the chain of custody document is printed and given to the donor. The donor is then dismissed. Preferably the cup/cap is then placed in the reader. 
     Step 4 of the foregoing sequence is automatically executed under the control of programmed microprocessor  36 . In step 4a, the piston has not yet been inserted into the cup and may partially obscure the field of view. In addition, since the piston is not down, the light shield is only partially effective, and extraneous light may enter, further obscuring details. Nevertheless, an initial image is captured by the camera to examine the primary barcode  120  and other cap features to determine if it is valid. If the barcode is not valid, this fact is displayed to the site administrator for further action. An invalid barcode can indicate that the cup is inserted incorrectly, that there is no cup there at all, or that a “fake” cup has been inserted. If the administrator cannot resolve the issue and the barcode is indeed invalid, testing is aborted and the sealed cup is sent for laboratory analysis. 
     In step 4b, processor  36  runs the piston motor  42  to lower the piston  164  a predetermined distance. This also lowers the light shield  192  into place against the cap top surface  96  so that the light source  38  is then the only source of light illuminating the cap top. The light source  38  preferably comprises multiple green LED&#39;s inasmuch as the lines that appear on typical component test strips exhibit the highest contrast when viewed in green light. With the piston in its down position, it no longer obscures any cap features within the image field  125 . 
     In step 4c, another image of the cap is captured and processed to double-check the primary barcode results from the previous step and to read the secondary barcode  121  and the fiducial marks  122 . The fiducial marks  122  are small features printed on the cap directly above the test strip windows  114 A,  114 B and serve as reference points for subsequent processing steps to assure accurate image analysis. Preferably, the barcode labels have their own fiducial marks, which allow the barcodes to be found and read even if the label is askew. If all barcodes and fiducial marks can be located and properly read, then operation proceeds to step 4d. Otherwise, the site administrator is alerted and he/she decides whether to proceed or not. 
     The test strips take between two and eight minutes to develop. During step 4d, images are periodically captured and during step 4e, the images are processed and analyzed. Steps 4d and 4e are executed in an iterative loop. If all latent lines become visible after two minutes, the test is concluded and operation proceeds to step 4f. Otherwise steps 4d and 4e are executed every minute until eight minutes have elapsed. If any of the drug or control lines do not become visible, the assaying device is sent to the lab for further analysis. 
     The image analysis executed in step 4e includes an extensive procedure to be discussed hereinafter for discerning a color change on the adulteration test strip and visible reference and drug lines on the component test strip. The detection of these lines can be reasonably challenging because the amplitude, i.e., dark or light, of its pixels can vary widely dependent on several factors including variations in test strips, in wetting, in urine color, etc. In order to produce an optimum image for analysis, a sequence (e.g., 8) of images is actually captured. These multiple images are then mathematically summed divided by the number of images in order to produce an integrated image in which the random electrical and optical “noise” has been reduced by this “averaging” process. This integrated image is then used in the subsequent line detection procedure:
         4e(1) The fiducial marks  122 , which had been found to exist in step 4c, are now located precisely by looking in a restricted region (as a consequence of the cup being physically positioned by keyed recess  70 ) and finding the centroid of the individual fiducial marks. This determines their exact locations within the camera field of view (i.e., 640×480).   4e(2) Based on the locations of the fiducial marks, the image is now rotated, translated, minified, and or magnified as necessary so that the resulting image has the fiducial marks  122  (and hence all other cap features) in “standard” positions which is hence presumed for all subsequent operations.   4e(3) Using a “map” of the features present on the cap top, each test is individually examined. Although the two test strips can in fact differ in the number of lines present and their specific locations, for the sake of simplicity, the operations on only one typical test strip will be described.   4e(4) Based on known default reference and drug line positions, non-overlapping rectangular regions  200  are “drawn” around each reference line  117 R and drug line, e.g.,  117 D ( FIG. 10B ).   4e(5) For the region  200  which contains the reference line  117 R, row sums are produced. The number of pixels summed for each row is the “width” of the test strip (e.g.,  32  in  FIG. 10C ), the number of total row sums for each region is the “height” of the individual region (e.g.,  48  in  FIG. 10C ). Each of these row sums produces a graph ( FIG. 10D ) whose X axis is related to the “height” of the region, and whose Y axis is related to the values of individual row sums. Let it be assumed that individual row sums will be smaller for darker horizontal rows and larger for lighter horizontal rows. The resulting graphs are then preferably normalized so that the Y axis values are between 0 and 100, and then subtracted from 100 so that the darkest row in a given region has the value 100 and the brightest row in a given region has the value 0. Bell shaped curves will result (presuming a drug or control line is present) as depicted in  FIG. 10D .   4e(6) The reference line  117 R must be located in order to proceed further and its exact position must be determined in order to locate the best estimated positions of the drug lines for further processing. The graph for the reference line is examined for a maximum value, which represents the reference line center position. After the center position is located, the regions drawn in substep 4e(4) above are redrawn to center the reference line and drug lines in their respective regions.   4e(7) For each drug region, row sums and the resulting graph are produced as described in substep 4e(5) above.   4e(8) Each drug region graph is divided into three equal parts, a left, center, and right part as represented in  FIG. 10F . The drug line is presumed to occupy the center portion. However, its exact position and width can vary, and its brightness difference in relation to the neighboring area may be very subtle. Based on different wetting conditions, a dark condition in one region can in fact be lighter than a not-dark condition in another region. Hence, a relative mechanism is used to determine the presence or absence of a drug line.   4e(9) For each drug region graph, the total area under each of the three regions (left, center, right) is calculated. The left and right region areas are then numerically summed, and this resulting total area sum is multiplied by an experimentally determined “weighting value”, thus producing a weighted sum. If the area of the center region is greater than this weighted sum, a decision is made that a line is present. If the area of the center region is less than or equal to the weighted sum, a decision is made that no line is present. By using urine samples with known drug concentrations, a weighting value of 0.75 has been found to produce very acceptable results. In order to conceptually understand what is going on, presume that the graph is perfectly symmetric and the drug line is centered in the graph, hence the graph will appear as a bell curve ( FIG. 10F ) (this is typical of the actual graphs produced) if a line is present, or at the other extreme, will appear as a flat line if no drug line is present. In the case of a flat line, then the summed areas of the left and right region will be exactly twice (2*X) the area of the center region (X). If the 2*X value is weighted by 0.75, the resulting area is now 1.5*X, which is greater than X. Hence no drug line is considered present. In fact, the weighting value would have to be less than 0.5 for a line to be considered present. As the center region grows in amplitude, its area reaches a point that it is now greater than the weighted sum of the left and right regions, and a line is considered present. Note that the presence or absence of a line is not determined by the exact position or shape of this curve, nor by the exact amplitudes of the dark and light components, which can vary widely based on various factors including the degree of wetting, the color of the urine, the particular lot of test strips, the time of exposure, extraneous material on the test strip, and shadows and/or reflections. All of these variations are compensated for in the relatively simple and concise mathematical procedure described which allows the presence or absence of drug lines to be repeatedly determined to a controllable, high degree of accuracy.       

     Once all adulteration test strips have been examined for color and all component test strips examined for visible lines, a final test result, for adulteration and identification of drug lines present and/or absent, is locally displayed and/or communicated to the host computer in accordance with aforementioned step 4f. 
     The foregoing describes applicants&#39; preferred system for automatically testing fluid specimens to detect specific chemical components therein. The preferred system includes an assaying device comprised of a fluid collection cup and a cap carrying one or more test strips configured to produce visually discernable indications of the components of the specimen and/or specimen adulteration. The visual indications are read by an imager, e.g., digital camera, and interpreted by a processor which executes an analysis procedure to interpret the visual indications. The resulting test results are reported locally or via a communications network to a host computer. Thus, systems in accordance with the invention can quickly (e.g., in less than 15 minutes) and locally automatically test a fluid specimen to provide accurate qualitative test results. The system both assures the confidentiality of donor/specimen test results (by using machine readable, rather than human readable, markings) and a closely controlled chain of custody procedure. 
     Although a preferred embodiment has been described, it is understood that many modifications and variations will occur to those skilled in the art which fall within the intended scope of the invention as defined by the appended claims.