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:
This application claims the benefit under Title 35 USC 119(e) of U.S. provisional patent application No. 60/143,194, filed on Jul. 7, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a collection assembly and more particularly to a microcollection container and cap suitable for collecting small quantities of a specimen such as blood from a patient and providing 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. 
     2. Description of Related Art 
     Analytical instrumentation has made it possible to carry out a variety of hematological diagnostic procedures on very small quantities of blood. Because of this, a patient&#39;s finger or earlobe, for example, may be punctured and a very small quantity of blood may be rapidly collected into a container for such testing. Once the small quantities of blood are collected, the container is sealably covered by a cap. 
     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. 
     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 
     The present invention is a collection assembly comprising a container and a cap. The cap preferably comprises a top portion, a bottom portion, and an annular skirt extending from the top portion to the bottom portion having an inner surface and an outer surface. The cap further includes an inner inverted skirt portion surrounded by the inner surface of the annular skirt. Most preferably the inner inverted skirt portion is separated from the inner surface of the annular skirt by an annular space. The inner inverted skirt extends between an upper extent and a lower extent whereby the lower extent supports a septum or membrane. Desirably, the septum is a disc-like membrane formed of a self-sealing and resealing thermoplastic elastomer material. 
     Most preferably, the septum is capable of being pierced and resealed on a repetitive basis with a piercing element such as a needle or instrument probe. Most preferably, the septum is formed of a thermoplastic elastomer. Such thermoplastic elastomer includes isoprene propylene, such as MONOPRENE (a trademark of QST, Inc.) sold by QST, Inc., St. Albans, Vt. 
     Preferably, the membrane and the cap body may be co-injection molded or insert molded. 
     Most preferably, the cap also includes a cam follower positioned on the bottom portion. Desirably, the inside surface of the annular skirt comprises at least one protrusion and the inner inverted skirt portion has a sealing ring. The cap further comprises a rim extending from the outer surface of the annular skirt. 
     The container preferably comprises an open top portion, a closed bottom portion, a sidewall extending from the top portion to the bottom portion and an open end associated with the top portion having an integral collector. Most preferably, the integral collector is a scoop that is the same diameter as the inner diameter of the container so that no air vent is required. 
     Preferably, at least one lug is located on the outer diameter of the top portion of the container. 
     Preferably, the container further includes a cap seating flange associated with the outer diameter of the top portion of the container and an extending annular skirt associated with the bottom portion. Optionally, a reservoir is positioned within the cap seating flange and at least one lug is located in the reservoir. Preferably, the container also includes a locking ring associated between the integral collector and the cap seating flange. 
     Preferably, the collection assembly includes means for securing the inner surfaces of the cap to the top portion of the container by the interaction of the protrusions of the cap with the locking ring of the container and the sealing ring of the cap with the inside surface of the top portion of the container. Most preferably, the collection assembly also includes means for unsecuring the cap from the container by a cam arrangement on the cap and container. This cam arrangement assists in substantially reducing fluid splatter from the container when the cap is removed from the container. 
     In one embodiment of the invention, the cam arrangement includes at least one cam follower positioned on the bottom portion of the cap and at least one cam surface positioned on the outer diameter of the top portion of the container. A downwardly rotational force applied to the cap and an upwardly force applied to the container along the longitudinal axis, causes the cam follower and the cam surface to align and the cap to snap-seal to the container by the interaction of the protrusions of the cap with the locking ring of the container and the sealing ring of the cap with the inside surface of the top portion of the container. This action, which may cause an audible-snap, in turn seals the container by compressing the protrusions of the cap against the locking ring of the container and the sealing ring of the cap against the inside surface of the top portion of the container to form a non-permanent lock and to substantially prevent the outer surface of the top portion of the container from making contacting with the inside surface of the cap&#39;s annular skirt. 
     The cap and container are then unsecured in a twist off manner by applying a rotational force to the cap. Most preferably, an upward rotational force is applied to the cap and a downwardly force applied to the container along the longitudinal axis. This causes the cam follower to rise on the cam surface and in turn the cap is unsecured from the container. An important advantage of the present invention is that the rotational force applied to the cap can be bi-directional, that is clockwise or counter-clockwise. 
     In another embodiment of the invention, the cam arrangement includes at least one cam follower positioned on the bottom portion of the cap and at least one cam surface positioned in the cap seating flange of the container. 
     The collection assembly of the present invention is preferably used in micro-centrifuges. However, an extension may be secured and unsecured to the bottom portion of the container. The extension increases the length dimension of the container. With the extension, the container may be compatible with standard clinical centrifuges. 
     An advantage of the present invention is that any excess fluid on the outside surface of the integral collector is directed downwardly into the cap seating flange. Therefore, radial spray of excess fluid is minimized. 
     Another advantage of the invention is that the cap may be secured and unsecured to the bottom portion of the container. In particular, the annular space in the cap between the annular skirt and inverted skirt allows the cap to be removably secured with the bottom portion of the container by receiving the annular skirt of the container. 
     Still another advantage of the invention is that the recessed inverted skirt and the sealing-ring substantially reduces cap contact with fluid collected in the container. Therefore the inner surfaces of the cap may be minimally exposed to fluid collected in the container when the cap is secured to the top portion of the container. 
     Another advantage of the present invention is that the outer surface of the cap may preferably be configured to substantially limit movement or rolling of the cap or the assembly. This applies whether the cap is positioned with the top portion or bottom portion of the container. 
     Still another advantage of the present invention is that when the cap is secured to the container, the rim of the cap substantially prevents contamination to the specimen inside the container. 
     An advantage of the present invention is that it facilitates direct access to a sample or diagnostic instrumentation systems and enables microcollection tube compatibility with diagnostic instrumentation by providing features such as pierceability and self-resealing of the cap. 
     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. 
     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. 
     In addition, the present invention permits the assembly to be directly used on instrumentation similar to that used for evacuated collection assemblies. 
     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 
     FIG. 1 is a perspective view of the collection assembly of the present invention illustrating the container, the cap and the septum. 
     FIG. 2 is a side elevational view of the container of FIG. 1, partially in section of the cam surface area. 
     FIG. 3 is an enlarged cross sectional view of the cap of FIG. 1, taken along line  3 — 3  thereof. 
     FIG. 4 is a bottom view of the cap of FIG.  1 . 
     FIG. 5 is a side elevational view, partially in section of the collection assembly of FIG.  3 . 
     FIG. 6 illustrates the collection assembly of FIG. 5, with a probe extending thereinto. 
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, FIG. 1 illustrates a collection assembly  10  comprising a container  12  and a cap  14 . 
     As illustrated in FIG. 1, container  12  has a sidewall  22  having an outer surface  24  and an inner surface  26 . The sidewall extends from an upper portion  28  to a lower portion  30 . Upper portion  28  includes an open end  31 , an inner surface  27 , an outer surface  29  and a top surface  32  having an integral lip portion  34  with a receiving edge  36 . Lower portion  30  comprises a closed bottom end  38  and an annular skirt  37  extending from the closed bottom end and outer surface  24  to a bottom edge  47  so as to define a compartment area  39 . Annular skirt  37  provides a means for allowing the container to be placed upright on a flat surface. 
     Upper portion  28  has a cap seating flange  40  positioned around the outer surface of the container which defines a well or trough  42  and an outer surface  41 . The cap seating flange has an upper surface edge  43  and a plurality of lugs  44  each having a cam surface  46  in trough  42 . Although a container having only one projecting lug is within the purview of the instant invention, a plurality of lugs is preferred. Also, although other shapes and configurations are within the purview of the instant invention, lugs  44  of this embodiment are triangularly shaped. 
     As shown in FIG. 2, further positioned on the outer surface of the container on the upper portion is a locking ring  48  positioned between receiving edge  36  of integral lip portion  34  and cap seating flange  40 . The locking ring has an upper edge  50  and a lower edge  52 . 
     Cap  14  as shown in FIG. 3, has a top surface  54 , a bottom stop ledge  56  and an annular outer skirt  58  extending from the top surface to the bottom stop ledge. The annular outer skirt has an outer wall surface  60  and an inner wall surface  62 . A shield  66  extends from the outer wall surface of the annular outer skirt and has an outer surface or circumference  76 . 
     As shown in FIG. 3, cap  14  also has an inner annular inverted recessed skirt portion  64  that extends from top portion  54  to a bottom surface  63 . The inverted recessed skirt portion includes an open upper extent  100 , an opposed open lower extent  102  and a central passageway  65  therebetween which provides access through the cap and into the container. 
     The inner wall surface of the annular outer skirt and the inner annular inverted recessed skirt are spaced from each other to define an annular space  68 . The cap further includes, a plurality of circumferentially spaced protrusions  70  positioned on inner wall surface  62  and a sealing ring  67  positioned on inverted recessed skirt portion  64 . Projecting lugs  72  are located on bottom stop ledge  56  wherein each lug comprises a cam follower surface  74 . A second annular space  73  is between shield  66  and projecting lugs  72 . 
     Although a cap having only one projecting lug is within the purview of the instant invention, a plurality of lugs is preferred. Also, although other shapes and configurations are within the purview of the instant invention, lugs  72  of this embodiment are triangularly shaped. 
     As shown in FIG. 4, flats  77  are positioned on the outer surface of shield  66 . The flats substantially prevent the cap from rolling and provide a convenient grasping surface for ready removal and placement of the cap on the container. Although a shield with a smooth outer circumference without flats is within the purview of the instant invention, a shield with an outer surface with flats is preferred. 
     As shown in FIG. 5, cap  14  further supports a septum  110  at lower extent  102  of annular skirt  64 . Septum  110  is a disc-like membrane formed of a thermoplastic elastomer. 
     As shown in FIG. 5, septum  110  includes a planar portion  112  and an upwardly extending annular ridge  114 . Annular ridge  114  has a diameter which allows it to be force fitted within open lower extent  102  of annular skirt  64 . Planar portion  112  faces towards the interior of the container. Annular ridge  114  defines a concave surface  116  in opposition to planar portion  112 . Septum  110  defines a centrally located portion  118  having a thickness of about 0.028 inches. Portion  112  allows the septum to be easily pierced by a cannula or probe that is used to extract a liquid sample from the interior of the container with only about 2 pounds of force. 
     When cap  14  is removably secured to container  12 , space  68  of the cap receives the top portion of the container including the integral lip, wherein the outer protrusions  70  bear against lower edge  52  of locking ring  48  of the container, sealing ring  67  bears against inner surface  27  of the container and cam follower  74  contacts cam surface  46 . Shield  66  extends around and not beyond outer surface  41  of cap seating flange  40  and bottom stop ledge  56  abuts with upper surface edge  43  of the cap seating flange  40 , so as to form a non-permanent lock and substantially prevent any excess fluid in well  42  of the cap seating flange from spilling out. Any fluid between upper surface edge  43  and bottom stop ledge  56  is substantially directed by shield  66  in a downward direction along the container. Further, any fluid in well  42  is substantially contained by the upper surface edge of the cap seating flange and the bottom stop ledge of the cap. 
     Cam follower surface  74  and cam surface  46  are configured so that a downwardly rotational force applied to cap  14  about longitudinal axis  80  causes cam follower  74  to contact cam surface  46 . Cap  14  is snapped onto the top portion of the container as guided by cam follower surface  74  and cam surface  46 . Cap  14  is removably secured to container  12  by protrusions  70  and sealing ring  67  as they bear respectfully against lower edge  52  of the locking ring and inner surface  27  of the container. The position of the protrusions and sealing ring of the cap with the container forms space  69  between outer surface  29  of the top portion of the container and inner wall surface  62  of the cap&#39;s annular outer skirt. Therefore, wiping down of any fluid on the container&#39;s outer surface is substantially prevented. 
     In use, a liquid sample is collected in container  12  and then the cap is securely secured to the open end of the container. 
     As shown in FIG. 6, a sample probe or cannula  120  may be inserted into container  12  by inserting cannula  120  through passageway  65 . The distal tip  122  of cannula  120  may then pierce through septum  110  at portion  118 . Since the material of septum  110  is a thermoplastic elastomer, septum  110  is easily pierced by low insertion forces. Therefore, for a relatively wide instrument probe having a diameter of about 0.0625 inches, portion  118  of septum  110  may be pierced by a force of less than 2 pounds. 
     Insertion of cannula  120  continues until it reaches the sample in the interior of the container and then collects a portion of the sample. Cannula  120  is then removed by withdrawing it back through passageway  65 . Upon withdrawing cannula  120  from septum  110 , the thermoplastic elastomer septum self-seals. In addition, concave surface  112  facing in opposition thereto helps reseal a hole placed in septum  110  by cannula  120 . The septum shape defines a concave surface in the direction of cannula withdrawal. The compressive forces exerted by such a shape have a tendency to effect resealing of any hole placed therein as cannula  120  is withdrawan from the container. Thus, the particular configuration of septum  110  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 the container can therefore be repeatedly sampled with the septum self-sealing upon each sample extraction. 
     The collection assembly of the invention may be made of a clear 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 may be applied to the internal surface thereof for enhancing the flow of blood introduced into the container. 
     Although is within the purview of the invention to provide caps which are colored to define 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.