Abstract:
The present invention is a collection assembly comprising a container, a cap assembly removably and sealably secured to the container whereby access to the interior of the container can be made with a piercing element without removing the cap assembly from the container. The cap assembly includes a cap body and a membrane like septum supported by the cap body. The septum provides for a pierceable element to have access to the interior of the container. The membrane is a thermoplastic elastomer and is self-sealing upon removal of the piercing element.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a collection assembly and more particularly to a microcollection container and cap assembly suitable for collecting small quantities of a specimen such as blood from a patient, that provides access to the interior of the container without the need for removing the cap from the assembly and for maintaining a specimen in secure fashion for subsequent testing.  
           [0003]    2. Description of Related Art  
           [0004]    Analytical instrumentation has made it possible to carry out a variety of hemological diagnostic procedures on very small quantities of blood. The blood may be collected from a small puncture placed in a patient&#39;s finger or ear lobe. The blood is collected in a microcollection container. Once the small quantities of blood are collected, the container is sealably covered by a cap.  
           [0005]    In order for a laboratory technician to conduct tests on the blood sample which is collected in the container, the cap must be removed from the container so as to provide access to the blood sample. In the alternative, the entire contents of the container may be transferred from the container to an instrument compatible sample holder in order for laboratory analysis to take place.  
           [0006]    Therefore, there is a need for a microcollection container that is (i) compatible with instruments for laboratory analysis whereby the specimen does not have to be transferred out of the container for analysis to be conducted; (ii) provides a resealable portion for easy access into the container by a needle or probe that also prevents specimen leakage out of the container; (iii) maintains a specimen in secure fashion; and (iv) prevents contamination to the specimen and to the user.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention is a collection assembly comprising a container and a cap.  
           [0008]    The container includes an open end, a closed end and a cylindrical wall therebetween which preferably comprises the interior of the container for accommodating the specimen.  
           [0009]    Desirably, the cap comprises a cap body removably sealably secured to the open end of the container. The cap body supports a membrane for providing reseable access to the interior of the container. The membrane is formed of a material which is capable of being pierced and resealed on a repetitive basis with a needle or instrument probe. Most preferably, the membrane is formed of a thermoplastic elastomer. Such thermoplastic elastomers include isoprene propylene, such as MONOPRENE (a trademark of QST, Inc.) sold by QST, Inc., St. Albans, Vermont.  
           [0010]    Preferably, the membrane is disc-shaped having a concave surface facing away from the container interior which assists in resealing of the membrane. The thermoplastic elastomer allows for the resealing of the pierced membrane in a manner which prevents specimen leakage therethrough even when the collection assembly is held in an inverted position.  
           [0011]    Preferably, the cap body includes a top portion, a bottom portion, a cylindrical sidewall extending from the top portion to the bottom portion having an inner surface and an outer surface, an access passageway at the top portion and a membrane supported across the passageway.  
           [0012]    The cap body may further include a depending annular skirt extending into the interior of the container from the top portion and defining an annular region with the cylindrical sidewall. The open end of the container is accommodated within the annular region. The depending skirt includes an access passageway, with the membrane being supported across the passageway.  
           [0013]    Preferably, the membrane and the cap body may be co-injection molded or insert molded.  
           [0014]    An advantage of the present invention is that it facilitates direct access to a sample for diagnostic instrumentation systems and enables microcollection tube compatability with diagnostic instrumentation by providing features such as pierceability and self-resealing of the cap.  
           [0015]    Still another advantage of the present invention is that the self-sealing pierceable cap permits mixing of the specimen in the container without transferring the specimen to another container and providing for direct access to the specimen via the self-sealing pierceable cap by diagnostic instrumentation.  
           [0016]    Most notably, is that the present invention permits a specimen to be accessed through the top of the cap without removing the cap from the container, thereby providing minimal exposure of the specimen to the user.  
           [0017]    In addition, the present invention permits the assembly to be directly used on instrumentation similar to that used for evacuated collection assemblies.  
           [0018]    Advantages of the membrane of the present invention include that: (i) it can be pierced and resealed many times; (ii) it requires less than 2 lb. force for a piercing element to pierce it; and (iii) the concave shape aids in the ability of the membrane to seal properly after the piercing element is removed. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a front plan view of the collection assembly of the present invention.  
         [0020]    [0020]FIG. 2 is a perspective view of the collection assembly of FIG. 1 illustrating the container, the cap and the membrane.  
         [0021]    [0021]FIG. 3 is a cross sectional view of the collection assembly of FIG. 1.  
         [0022]    [0022]FIG. 4 is a side elevational view, partially in section of the collection assembly of FIG. 3.  
         [0023]    [0023]FIG. 5 illustrates the collection assembly of FIG. 4, with a probe extending thereinto. 
     
    
     DETAILED DESCRIPTION  
       [0024]    Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, FIGS.  1 - 3  illustrate the collection assembly  10  of the present invention.  
         [0025]    Collection assembly  10  includes a container  12  and a cap assembly  14 . Cap assembly  14  may be removably secured to the container.  
         [0026]    Container  12  is an elongate member having an open upper end  16 , a lower end  18  including a rounded closed bottom  19  and a cylindrical wall  20  extending therebetween. The cylindrical wall  20  defines an interior  17  internally thereof for accommodating a specimen such as a blood specimen. The cylindrical wall  20  extends beyond the rounded closed bottom  19  to form an annular extension  22  which permits container  12  to stand upright on a flat surface.  
         [0027]    As shown in FIG. 2, open upper end  16  of container  12  includes a beveled distal rim  24  for facilitating collection of a blood sample. The upper end  16  of tube  12  further includes a radially outwardly extending cap seating flange  26  which provides for the removable sealable attachment of cap assembly  14  on upper end  16  of container  12 . Once a specimen, such as blood is collected in interior  17  of the container, the container may be sealingly closed by cap assembly  14 .  
         [0028]    Referring to FIG. 4, cap assembly  14  includes a cap body  30  and a sealable septum  32  supported by cap body  30 . Cap body  30  is preferably an integrally formed molded plastic member generally in the shape of an inverted cup. The cap includes a flat upper surface  34 , an opposed open lower surface  36  and a cylindrical sidewall  38  extending therebetween. The distal end of cylindrical sidewall  38  adjacent open lower surface  36  defines an annular groove  39  for accommodating cap seating flange  26  of the container. Cylindrical side wall  38  includes a plurality of inwardly directed protrusions  40  which engage an exterior surface of cylindrical wall  20  of the container about open upper end  16  to provide sealed engagement between cap body  30  and container  12 .  
         [0029]    Cap body  30  further includes a centrally located depending annular skirt  42  extending from flat upper surface  34 . Annular skirt  42  and cylindrical side wall  38  form an open ended annular recess  43  therebetween for accommodating upper end  16  of container  12 . Annular skirt  42  includes an open upper extent  44 , an opposed open lower extent  46  extending into interior  17  of the container and a central passageway  45  therebetween which provides access through cap body  30  and into interior  17  of container  12 . Lower extent  46  of annular skirt  42  includes an outwardly directed annular rib  48  which is engageable with an inner surface of cylindrical wall  20  adjacent open upper end  16  of container  12  to facilitate sealing of cap body  30  with container  12 .  
         [0030]    Cap body  30  further supports septum  32  at the lower extent  46  of annular skirt  42 . Septum  32  is a disc-like membrane formed of a thermoplastic elastomer. As shown in FIG. 4, septum  32  includes a planar portion  50  and an upwardly extending annular ridge  52 . Annular ridge  52  has a diameter which allows it to be force fitted within open lower extent  46  of annular skirt  42  and retained in sealed engagement. Planar portion  50  of septum  32  faces towards the interior of container  12 . Annular ridge  52  defines a concave surface  53  in opposition to planar portion  50 . Septum  32  defines a centrally located portion  54  having a thickness of about . 028  inches. Portion  54  allows the septum to be easily pierced by a cannula or probe used to extract a liquid sample from interior  17  of container  12  with about 2 pounds of force.  
         [0031]    In use, a liquid sample is collected in container  12  and then cap assembly  14  is sealably secured to the open upper end of the container.  
         [0032]    As shown in FIG. 5, a sample probe or cannula  60  may be inserted into container  12  by inserting cannula  60  through passageway  45  of cap body  30 . The distal tip  62  of cannula  60  may then pierce through septum  32  at portion  54 . Since the material of septum  32  is a soft thermoplastic elastomer, septum  32  is easily pierced by low insertion forces. Therefore, for a relatively wide instrument probe having a diameter of about 0.0625 inches, portion  54  of septum  32  may be pierced by a force of less than 2 pounds.  
         [0033]    Insertion of cannula  60  continues until it reaches the sample in interior  17  of container  12  and then collects a portion of the sample. Cannula  60  is then removed by withdrawing it back through passageway  45 . Upon withdrawing cannula  60  from septum  32 , the thermoplastic elastomer septum self-seals. In addition, concave surface  50  facing in opposition thereto helps reseal a hole placed in septum  32  by cannula  60 . The septum shape defines a concave surface in the direction of cannula withdrawal. The compressive forces exerted by such a shape assist in resealing of any hole placed in septum  32  as cannula  60  is withdrawn from the container. Thus, the particular configuration of septum  32  as well as the material from which it is formed permits the septum to reseal after multiple puncture sites have been placed therein. The liquid sample in container  12  can therefore be repeatedly sampled with the septum self-sealing upon each sample extraction.  
         [0034]    The collection assembly of the invention may be made of a molded thermoplastic material so that the specimen collected may be readily viewed. Representative materials include, for example, polyethylene, polypropylene and polyvinyl chloride. The collection container may incorporate a hydrophilic material or a silicon, or a texture may be applied to the internal surface thereof for enhancing the flow and mixing of blood introduced into the container.  
         [0035]    Although it is within the purview of the invention to provide caps which are colored to defined specific forms of fluid collection containers containing materials for one reason or another or for defining the kind of examination to be conducted on the specimen collected, transparent caps may be provided. Also, it should be noted that the dimensions of the container are such as to provide space for labeling which may be important for identifying the collected specimens.