Abstract:
A plurality of container assemblies are provided. Each container assembly has substantially identical external dimensions. However, the internal volumes of certain container assemblies differ from the internal volumes of other container assemblies. The container assemblies are configured in accordance with the required volume of material to be collected or maintained in the respective container assemblies and to enable uniform head spaces despite the different volumes of materials in the respective container assemblies. Each container assembly may have an inner container and an outer container. The inner and outer containers may be assembled together or formed integrally by molding.

Description:
RELATED APPLICATIONS  
       [0001]    This application claims priority on U.S. Provisional Patent Appl. No. 60/405,048, filed on Aug. 20, 2002 and is a continuation-in-part of pending U.S. patent application Ser. No. 09/933,653 and U.S. patent application Ser. No. 10/114,542. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The invention relates to collection containers, such as collection containers used for collecting specimens of bodily fluid.  
           [0004]    2. Description of the Related Art  
           [0005]    Tubes are used to collect specimens or samples of bodily fluid. The typical tube includes a cylindrical sidewall with a spherically generated closed bottom and an open top. A closure is mounted to the open top to permit sealing of the tube. The closure typically comprises an elastomeric stopper that is urged into the open top of the tube. The closure also may include a rigid plastic member that retains the elastomeric stopper. The plastic member can be used to manipulate the stopper for placing the closure in the open top of the tube or for removing the closure from the tube. The elastomeric stopper may be formed from a pierceable and resealable material. Some closures also include a layer of foil across the top of the closure for enhanced performance of the closure as a gas or moisture barrier. Tubes typically are formed from either glass or plastic. Glass tubes perform well as gas and moisture barriers, but are more fragile than plastic tubes. Hence, glass tubes may require special handling. Plastic tubes are substantially unbreakable. However, certain plastics may be permeable to gases or moisture.  
           [0006]    A sample of fluid collected in a tube typically is sent to a laboratory for analysis. Characteristics of the collected sample may change if the sample is exposed to ambient gases or if vapors produced by the sample are permitted to permeate through the walls of the tube and into the ambient surroundings. Characteristics of the collected sample also may vary after exposure to gas trapped between the surface of the collected fluid sample and the stopper. The volume between the top of the collected sample and the stopper is referred to herein as the head space.  
           [0007]    Most laboratory analysis of collected fluid samples are performed with automated or semi-automated equipment. The equipment typically is geared to accommodate tubes of specified outside dimensions. Tubes that are too small may require separate handling, and hence tubes with non-standard outside dimensions may require slower less efficient and more costly analysis of the specimens collected therein. Accordingly, most health care facilities collect specimens in standard sized tubes. However, some tests can be performed with relatively small volumes of a fluid sample. A collection of a small volume sample in a relatively large tube necessarily creates a large head space with a large volume of air above the collected sample. Accordingly, there is a greater probability that characteristics of a small collected sample will vary prior to testing due to interaction or reaction with the relatively large volume of air in the head space.  
           [0008]    It is desirable to provide a tube with standard outside dimensions. It is also desirable to collect only the smallest volume of a sample that is required for a particular laboratory analysis. Furthermore, it is desirable to provide a smaller and substantially uniform head space.  
         SUMMARY OF THE INVENTION  
         [0009]    The subject invention is directed to sample collection containers. The sample collection containers have selected outside dimensions to conform with instruments and equipment employed in a laboratory. The sample containers, however, have wall dimensions selected to achieve a small and uniform head space between the top of the collected sample and the bottom of the closure.  
           [0010]    The container may be a tube with a substantially cylindrical outer surface. The bottom of the tube may be closed and may have a substantially spherically generated outer surface. The top of the tube is open.  
           [0011]    The walls of the container may be of different thicknesses at various locations between the closed bottom of the container and the open top. For example, walls of the container adjacent the open top may have a thickness selected in accordance with strength requirements of the container and/or in accordance with standard dimensions for the closure. The walls of the container spaced from the open top, however, may have a thickness greater than the thickness of the container at the open top. The greater thickness of the container walls at locations spaced from the open top function to reduce the volume of the space in the container. Thus, a small volume of a fluid sample can be collected without significantly increasing the head space and achieving a desirably low sample to head space volume ratio.  
           [0012]    The collection container may be formed from a plastic material by a molding process, such as co-injection, two-shot molding or other known process to provide an integral or unitary matrix of plastic between inner and outer surfaces of the container. Alternatively, the collection container may comprise a plurality of nested containers. The nested containers may comprise an outer container of substantially uniform wall thickness and an inner container with a variable wall thickness. The inner container can be slidably inserted into the outer container so that the two containers function as a single container assembly. The variable thickness of the inner container may comprise a thin wall portion adjacent the open top of the inner container and a thick wall portion adjacent the bottom of the inner container. The thickness of the thick wall section of the inner container is selected to achieve a small head space that can be uniform for a range of collected specimens of a particular type and a particular volume. The thin wall section of the inner container may be dimensioned for engagement by at least part of the closure.  
           [0013]    The outer surface of the inner container and/or the inner surface of the outer container may be formed with surface configurations to facilitate nesting of the two containers. The surface configurations can include a roughening along at least a portion of the outer surface of the inner container or the inner surface of the outer container. The roughening defines an array of peaks and valleys, and air that would otherwise be trapped between the containers can escape through the valleys as the containers are being assembled. Hence, an air lock is not likely to be created as the inner and outer containers are assembled. Furthermore, compressed air will not exist in the minute spaces defined between the inner and outer containers, and accordingly migration of air through the inner wall of the inner container is substantially reduced or eliminated.  
           [0014]    The invention also is directed to a system of containers. All of the containers in the system have uniform outside shapes and dimensions. However, the wall thicknesses of the containers vary among groups of containers within the system. As a result, the volume of fluid that can be collected by the containers in the system varies among at least certain of the containers. The volume is inversely related to the thickness of the walls of the containers. All of the containers within the system, however, provide a substantially uniform head space. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a side elevational view of a tubular container in accordance with the subject invention.  
         [0016]    [0016]FIG. 2 is a perspective view of the container shown in FIG. 1.  
         [0017]    [0017]FIG. 3 is a top plan view of the container show in FIGS. 1 and 2.  
         [0018]    [0018]FIG. 4 is a cross-sectional view taken along line  4 - 4  in FIG. 3.  
         [0019]    [0019]FIG. 5 is a longitudinal cross-sectional view of a second embodiment of a container assembly in accordance with the subject invention.  
         [0020]    [0020]FIG. 6 is an exploded perspective view of the container of FIG. 5.  
         [0021]    [0021]FIG. 7 is a longitudinal cross-sectional view of a third embodiment of a container assembly in accordance with the subject invention.  
         [0022]    [0022]FIG. 8 is a longitudinal cross-sectional view of a fourth embodiment of a container assembly in accordance with the subject invention.  
         [0023]    [0023]FIG. 9 is a longitudinal cross-sectional view of a fifth embodiment of a container assembly in accordance with the subject invention.  
         [0024]    [0024]FIG. 10 is a longitudinal cross-sectional view of a sixth embodiment of a container assembly in accordance with the invention. 
     
    
     DETAILED DESCRIPTION  
       [0025]    A container in accordance with the subject invention is identified generally by the numeral  10  in FIGS.  1 - 4 . Container  10  includes a generally tubular sidewall  12 , a closed bottom  14  and an open top  16 . Tubular sidewall  12  includes a cylindrically generated outer surface  18  defining a diameter “a” as shown in FIG. 1. Closed bottom  14  of container  10  has a substantially spherically generated outer surface  20  characterized by a concave dimple  22  centrally disposed on the closed bottom.  
         [0026]    Tubular sidewall  12  of container  10  is further characterized by an inner surface  24  of substantially stepped cylindrical configuration. In particular, inner surface  24  includes a cross-sectionally small section  26  adjacent bottom end  14  of container  10  and a cross-sectionally large section  28  adjacent open top  16 . Cross-sectionally small section  26  has an inside diameter “b” as shown in FIG. 4, while cross-sectionally large section  28  has an inside diameter “c”. Inside diameter “c” at cross-sectionally large section  28  is dimensioned to achieve tight engagement with a closure (not shown in FIGS.  1 - 4 ). Container  10  is molded unitarily from a plastic material by a molding process.  
         [0027]    The stepped inside surface  24  of container  10  enables a small volume of fluid to be collected without altering outside dimensions of container  10 . Thus, outside diameter “a” enables container  10  to be used with standardized laboratory equipment. However, the stepped cylindrical inner surface  24  enables a small volume of fluid to be collected in container  10  without an undesirably large head space.  
         [0028]    Container  10  may have a sidewall  12  and a bottom wall  14  with thicknesses dimensioned to achieve a volume ranging from about 1 mL to about 4 mL. Fluid samples of these volumes are acceptable for many testing procedures and enable a head space in the range of 5-16 mm (i.e., 0.8-1.5 mL) to be achieved. Tubes of similar construction but with different wall thicknesses and different inside diameters for inner surface  24  can be used to achieve different fluid volumes without significantly affecting the head space. Container  10  can be used with a closure, such as an elastomeric stopper inserted into open top  16 . The stopper may function to maintain a vacuum in container  10  so that container  10  can be used for drawing a sample of blood.  
         [0029]    The embodiment of the invention depicted in FIGS.  1 - 4  shows tube  10  formed from plastic material by a co-injection process or other molding process familiar to those in the art. For example, an outer portion of tube  10  may be molded from a first plastic and an inner portion may be molded from a second plastic. The co-injection or other molding process achieves an integral or unitary matrix of plastic between inner and outer surfaces  24  and  18 . The plastics selected for the inner and outer portions of tube  10  are selected in accordance with specific requirements, such as compatibility with the stored material, liquid impermeability, gas impermeability and such. FIGS.  5 - 8  show an alternate embodiment where tube assemblies comprise inner and outer tubes. In particular, FIGS. 5 and 6 show a tube assembly  40  with an outer container  42  and an inner container  44 . Outer container  42  includes a substantially cylindrical tubular sidewall  46 , a closed bottom  48  and an open top  50 . Tubular sidewall  46  includes a cylindrically generated outer surface  52  and a cylindrically generated inner surface  54 . Outer surface  52  and inner surface  54  of outer tube  42  are of substantially uniform cross-section along the entire length of tubular sidewall  46 . Thus, tubular sidewall  46  is of substantially uniform thickness along its length.  
         [0030]    Inner tube  44  includes a tubular sidewall  56 , a closed bottom  58  and an open top  60 . Tubular sidewall  56  has an outer surface  62  and an opposed inner surface  64 . A roughened region that defines an array of peaks and valleys extends along at least a portion of the outer surface  62 , as shown most clearly in FIG. 6. The diameter defined by the peaks on outer surface  62  of tubular sidewall  56  substantially equals the inside diameter of inner surface  54  on sidewall  46  of outer tube  42 . The valleys between the peaks on the roughened outer surface  62  define an outside diameter that is less than the inside diameter of inner surface  54  of sidewall  46  on outer tube  42 . The valleys on roughened outer surface  62  define circuitous or tortuous paths that permit an escape of air A as inner tube  44  is being inserted into outer tube  42 . Thus, assembly of tubes  42  and  44  is easier and there is no build-up of high pressure air between inner and outer tubes  42  and  44 .  
         [0031]    Inner surface  64  of inner tube  44  has a substantially cylindrical portion  66  extending up from closed bottom  58  and an outwardly tapered portion  68  adjacent open top  60 . Cylindrical portion  66  of inner surface  64  defines an inside diameter “d”. Inside diameter “d” is selected to achieve a preferred volume for tube assembly  40 . In the illustrated example of FIG. 5, tube assembly  40  accommodates 3.5 ml.  
         [0032]    Tube assembly  40  is employed with a closure  70  to seal inner tube  44  and outer tube  42  adjacent the respective open tops  60  and  50 , and in some embodiments to maintain a low pressure. Thus, a selected volume of blood can be collected in tube assembly  40  by placing the evacuated interior of tube assembly  40  in communication with a blood vessel. This communication can be achieved with a conventional needle holder, a blood collection set or other known means. In the illustrated example, closure enables the 3.5 mL fluid sample to be collected, while retaining a head space of approximately 5-16 mm (i.e., 0.8-1.5 mL).  
         [0033]    [0033]FIG. 7 illustrates a tube assembly  80  that is similar to tube assembly  40 . In particular, tube assembly  80  includes an outer tube  42  identical to outer tube  42  described above with respect to FIG. 5. Tube assembly  80  further includes an inner tube  84  that is similar to inner tube  44  of tube assembly  40 . In particular, inner tube  84  has a tubular sidewall  86 , a closed bottom  88  and an open top  90 . Tubular sidewall  86  has an outer surface  92  that may be substantially identical to the outer surface  62  of inner tube  40 . Inner tube  84  further includes an inner surface  94  with a cylindrically generated section  96  adjacent closed bottom  84  and an outwardly tapered section  98  adjacent open top  90 . Cylindrically generated section  96  of inner surface  94  defines an inside diameter “e” that is less than inside diameter “d” of cylindrical portion  66  on inner surface  64  of inner tube  44 . As a result, tube assembly  70  can accommodate a volume of about 3.0 mL while achieving a head space of 5-16 mm (i.e., 0.8-1.5 mL) substantially equal to the head space achieved with tube assembly  40 .  
         [0034]    [0034]FIG. 8 shows a tube assembly  100  with an outer tube  42  substantially identical to outer tube  42  of tube assemblies  40  and  80 . Tube assembly  100  also includes an inner tube  104  that has a tubular sidewall  106 , a closed bottom  108  and an open top  110 . Tubular sidewall  106  has an outer surface  112  that may be substantially identical to outer surface  62  of sidewall  56  on inner tube  44 . Tubular sidewall  106  further has an inner surface  114  with a cylindrically generated section  116  adjacent closed bottom  108  and an outwardly flared section  118  adjacent open top  110 . Cylindrically generated section  116  of inner surface  114  defines an inside diameter “f” that is less than inside diameter “e” of inner tube  84 . As a result, tube assembly  100  can accommodate a fluid sample of only about 2.0 ml, while achieving a head space of 5-16 mm (i.e., 8-1.5 mL) substantially equal to the head spaces of the tube assemblies  40  and  80 .  
         [0035]    The system of tubes depicted in FIGS.  5 - 8  enables collection of a fluid sample of appropriate size for a particular laboratory test to be performed, but without affecting the head space.  
         [0036]    The reduced volume and substantially uniform head space can be achieved by providing an effectively thicker bottom wall as shown in FIG. 9 instead of or in addition to the variable thickness of the sidewalls. In particular, FIG. 9 shows a tube assembly  120  with an outer tube  42  substantially identical to the outer tube  42  shown in FIGS.  5 - 8 . Additionally, tube assembly  120  includes a closure  70  that may be substantially identical to the closures shown in FIGS.  5 - 8 . Tube assembly  120  further includes an inner tube  124  with a projection  126  at the closed bottom end thereof. As a result, a raised bottom wall  128  is spaced considerably above closed bottom  48  of outer tube  42 . Accordingly, inner tube  124  defines a smaller volume than inner tube  44  in the embodiment of FIGS. 5 and 6 without an increase in wall thickness. Furthermore, the projection  126  enables the closed bottom of inner tube  124  to be raised without a significant increase in thickness of inner tube  124 . In this latter regard, a significantly increased thickness at the bottom of inner tube  124  could complicate molding.  
         [0037]    The container of the subject invention may include closures that extend greater distances into the container for reducing the head space and achieving a substantially uniform head space for different volumes of fluid. In particular, FIG. 10 shows a container assembly  130  with an outer tube  42  substantially identical to the outer tube of the embodiments shown in FIGS.  5 - 9 . Assembly  130  further includes an inner tube  134  that is very similar to inner tube  44  in the embodiment of FIGS. 5 and 6. However, inner tube  134  is shorter than inner tube  44 . Tube assembly  130  further includes a closure  170  that is similar to closure  70  on the embodiments of FIGS.  5 - 9 . However, closure  170  includes an internal section  172  with a length “h” that exceeds the corresponding length of closure  70  shown in the embodiments of FIGS.  5 - 9 . The greater length “h” compensates for the shorter length of inner tube  134  and effectively reduces both the volume of tube assembly  134  and the head space. The different length closures  170  can be used with or instead of the different effective thicknesses for the bottom wall (FIG. 9) and/or the different thicknesses for the sidewalls (FIGS.  5 - 8 ).