Patent Publication Number: US-9889442-B2

Title: Reagent preparation and dispensing device

Description:
PRIORITY APPLICATIONS 
     This patent application is a continuation of U.S. patent application Ser. No. 13/988,279, filed Nov. 5, 2013, which claims priority benefit according to 35 U.S.C. 111(a) to International Patent Application serial number PCT/US2010/057238, filed Nov. 18, 2010, and published on May 24, 2012 as WO 2012/067619, which applications and publications are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     Storage, preparation and dispensing of solutions. 
     BACKGROUND 
     Some examples of diagnostic, life science research and drug discovery reagents require preparation prior to use. For instance, reagents may require measuring a diluent (or solution) and using the diluent to rehydrate a dry reagent. In other examples, preparation of the reagent requires measuring and mixing of a sample solution (e.g., a patient biological sample; an environmental sample such as, water or soil; an agricultural sample such as food and the like) with a reagent in a dried or liquid form. In still other examples, preparation of the reagent requires mixing of two or more liquid components, such as a reagent and another solution. 
     Manufacturers of diagnostic, life science research and drug discovery reagents use precision and standardized procedures in order to produce high quality reagents. These reagents are often prepared at their point of use. The quality of the reagents (e.g., the precise amount of reagent solution, the purity of the reagent solution and the like) is easily compromised at the point of use because of errors in preparation procedures that are used by personnel responsible for preparing the reagent. For instance, the reagent is handled in an unclean environment having contaminants (e.g., a humid atmosphere; a biologically active environment contaminated with microorganisms, DNA, RNA, ATP and the like; a chemically active environment, and the like), the wrong amount of solution is used, the wrong solution is used, and the like. In other examples, the reagent and solution or diluent are not allowed to mix thoroughly. In still other examples, the reagent solution is dispensed from a device but fails to deliver substantially all of the full specified amount of reagent solution as a result of operator error or device performance (e.g., a significant portion of the solution is left within the device). 
     Where lyophilized reagents (e.g., dried or freeze-dried reagents) are used, unwanted exposure to contaminants including, but not limited to, moisture or moisture vapor during storage and prior to reconstitution may contaminate or compromise the stability of the lyophilized reagent. Compromising the reagent decreases its ability to rapidly rehydrate thereby creating difficulties in preparing a reagent at the proper concentration. Additionally, compromising the reagent from a dry state (where biological and chemical activities of the reagent are arrested) may reactivate the reagent and allow it to prematurely break down thereby decreasing the effectiveness of the reagent. 
     Even small errors in preparation leading to an improperly prepared reagent (e.g., mis-measuring of a solution, failure to fully reconstitute the reagent or diluting the reagent and the like) may have undesirable consequences, including, but not limited to, false positives, inaccurate diagnoses leading to inaccurate or inappropriate treatments, and false negatives (undetected diagnoses resulting in no treatment where treatment is needed). 
     SUMMARY 
     In Example 1 an apparatus may comprise a body including a reaction chamber including a reagent, and a solution reservoir including a solution, the solution reservoir is isolated from the reaction chamber; a plunger movably coupled with the body, movement of the plunger from a starting position to a seated position pushes the solution into the reaction chamber; a dispensing path extending from the reaction chamber and out of the body, the dispensing path is configured to dispense a reagent mixture formed from the solution and the reagent; and a vent path extending from the reaction chamber, the vent path vents reaction chamber gas displaced by the addition of the solution to the reaction chamber throughout movement of the plunger from the starting position to the seated position. 
     In Example 2, the apparatus of Example may include a barrel movably coupled with the body, and the plunger is movably coupled with the barrel. 
     In Example 3, the apparatus of any one or any combination of Examples 1-2 may include the vent path extending through the barrel and along the plunger. 
     In Example 4, the apparatus of any one or any combination of Examples 1-3 may include the vent path extending along a barrel exterior through a first vent portion, and the vent path extends along a barrel interior through a second vent portion. 
     In Example 5, the apparatus of any one or any combination of Examples 1-4 may include a semi-permeable media is disposed in the vent path. 
     In Example 6, the apparatus of any one or any combination of Examples 1-5 may include the dispensing path in a sealed configuration. 
     In Example 7, the apparatus of any one or any combination of Examples 1-6 may include the dispensing path sealed with a frangible tip. 
     In Example 8, the apparatus of any one or any combination of Examples 1-7 may include a flushing chamber in the body, the flushing chamber is filled with a flushing fluid operable to push the specified amount of the reagent mixture through the dispensing path. 
     In Example 9, the apparatus of any one or any combination of Examples 1-8 may include the vent path extending through the flushing chamber. 
     In Example 10, the apparatus of any one or any combination of Examples 1-9 may include a second plunger operable to close the vent path, and the second plunger is operable to push the flushing fluid through the closed vent path into the reaction chamber. 
     In Example 11, an apparatus may comprise a body including a reaction chamber including a reagent, and a solution reservoir including a solution, the solution reservoir is isolated from the reaction chamber; a plunger movably coupled with the body, movement of the plunger pushes the solution into the reaction chamber; a dispensing path extending from the reaction chamber and out of the body, the dispensing path is configured to deliver a reagent mixture formed from the solution and the reagent; a flushing chamber including a flushing fluid in communication with the reaction chamber; and a vent path extending from the reaction chamber, the vent path includes open and closed configurations: in the open configuration, the vent path extend outside of the body, and the vent path vents reaction chamber gas displaced by the addition of the solution to the reaction chamber, and in the closed configuration, the vent path is closed, and flushing fluid delivered from the flushing chamber dispenses the reagent mixture through the dispensing path. 
     In Example 12, the apparatus of Example 11 may include a barrel movably coupled with the body, and the plunger is movably coupled with the barrel. 
     In Example 13, the apparatus of any one or any combination of Examples 11-12 may include the vent path extending through the barrel and along the plunger. 
     In Example 14, the apparatus of any one or any combination of Examples 11-13 may include the vent path extending along a barrel exterior through a first vent portion, and the vent path extends along a barrel interior through a second vent portion. 
     In Example 15, the apparatus of any one or any combination of Examples 11-14 may include a semi-permeable media disposed in the vent path. 
     In Example 16, the apparatus of any one or any combination of Examples 11-15 may include a sealed dispensing path. 
     In Example 17, the apparatus of any one or any combination of Examples 11-16 may include the dispensing path sealed with a frangible tip. 
     In Example 18, the apparatus of any one or any combination of Examples 11-17 may include the vent path extending through the flushing chamber. 
     In Example 19, the apparatus of any one or any combination of Examples 11-18 may include a second plunger operable to close the vent path, and the second plunger is operable to push the flushing fluid through the closed vent path into the reaction chamber. 
     In Example 20 an apparatus may comprise a body including a reaction chamber including a reagent, and a solution reservoir including a solution, the solution reservoir is isolated from the reaction chamber; a first plunger movably coupled with the body, movement of the first plunger pushes the solution into the reaction chamber with the reagent to form a reagent mixture; a second plunger movably coupled with the body, movement of the second plunger dispenses a specified amount of the reagent mixture from the body; and a vent path in communication with the reaction chamber, the vent path includes open and closed configurations: in the open configuration, the vent path extends from the reaction chamber to outside of the body, and the vent path vents gas displaced from the reaction chamber by the addition of the solution to the reaction chamber, and in the closed configuration, the vent path is closed. 
     In Example 21, the apparatus of Examples 20 may include the second plunger movable to close the vent path. 
     In Example 22, the apparatus of any one or any combination of Examples 20-21 may include the body including a flushing chamber containing a flushing fluid. 
     In Example 23, the apparatus of any one or any combination of Examples 20-22 may include the flushing chamber in communication with the vent path and the reaction chamber, and the second plunger is operable to push flushing fluid into the reaction chamber through the vent path in the closed configuration. 
     In Example 24, the apparatus of any one or any combination of Examples 20-23 may include the flushing chamber formed by the second plunger and a vent wall. 
     In Example 25, the apparatus of any one or any combination of Examples 20-24 may include a volume of the flushing chamber greater than a volume of the reaction chamber. 
     In Example 26, the apparatus of any one or any combination of Examples 20-25 may include the vent path extending from the reaction chamber between the body and a barrel movably coupled with the body. 
     In Example 27, the apparatus of any one or any combination of Examples 20-26 may include a semi-permeable media disposed in the vent path, the semi-permeable media retains the reagent mixture but not gas within the reaction chamber. 
     In Example 28 a method may include positioning a solution within a body; positioning a reagent within a reaction chamber in the body, the reagent is isolated from the solution; movably coupling an activator with the body, the activator is movable to force the solution into the reaction chamber and form a reagent mixture when the activator is moved from a starting position to a seated position; forming a closed dispensing tip extending from the reaction chamber and out of the body; and forming a vent path extending from the reaction chamber to outside of the body, the vent path vents gas from the reaction chamber displaced by the addition of the solution to the reaction chamber, and the vent path vents gas throughout movement of the activator from the starting position to the seated position. 
     In Example 29, the method of Example 28 may include movably coupling the activator with the body including movably coupling a plunger with the body. 
     In Example 30, the method of any one or any combination of Examples 28-29 may include forming the closed dispensing tip includes forming a frangible dispensing tip. 
     In Example 31, the method of any one or any combination of Examples 28-30 may include movably coupling a barrel with the body. 
     In Example 32, the method of any one or any combination of Examples 28-31 may include forming the vent path including extending the vent path between the barrel and the body. 
     In Example 33, the method of any one or any combination of Examples 28-32 may include forming the vent path including forming the vent path through the body from the reaction chamber, and forming the closed dispensing tip includes forming the closed dispensing tip extending from the reaction chamber in an opposed direction to the vent path. 
     In Example 34, the method of any one or any combination of Examples 28-33 may include forming a flushing chamber within the body, and the flushing chamber is in fluid communication with the reaction chamber through the vent path. 
     In Example 35, the method of any one or any combination of Examples 28-34 may include movably coupling a second plunger with the body, and the second plunger is operable to close the vent path and push a flushing fluid through the vent path into the reaction chamber. 
     In Example 36, the method of any one or any combination of Examples 28-35 may include forming the closed dispensing tip including extending the closed dispensing tip from a first portion of the reaction chamber, and forming the vent path includes extending the vent path from a second portion of the reaction chamber opposed to the first portion. 
     In Example 37 a method may include opening a sealed reaction chamber within a body, the reaction chamber containing a reagent; reconstituting the reagent with a solution retained within the body to form a reagent mixture, reconstituting including adding the solution to the reaction chamber; venting displaced gas from the reaction chamber, the gas is displaced by addition of the solution, the vented gas passing through a vent path extending through the body away from a dispensing tip; and dispensing a specified amount of the reagent mixture, dispensing including closing the vent path and pushing a flushing fluid through the vent path into the reaction chamber. 
     In Example 38, the method of Example 37 may include venting gas including preventing pressurization within the reaction chamber during reconstitution. 
     In Example 39, the method of any one or any combination of Examples 37-38 may include dispensing the specified amount of the reagent mixture including pressurizing the reaction chamber. 
     In Example 40, the method of any one or any combination of Examples 37-39 may include venting gas including venting gas through the body in a direction opposed to a direction of dispensing the specified amount of the reagent mixture. 
     In Example 41, the method of any one or any combination of Examples 37-40 may include reconstituting the reagent adjacent to the dispensing tip in a first portion of the reaction chamber, and the gas is vented from a second portion of the reaction chamber remote from the first portion. 
     In Example 42, the method of any one or any combination of Examples 37-41 may include reconstituting and dispensing of the specified amount of the reagent mixture are performed with the body in substantially the same orientation. 
     In Example 43, the method of any one or any combination of Examples 37-42 may include dispensing the specified amount of the reagent mixture including moving a plunger relative to the body, and closing the vent path includes engaging the plunger with a vent wall to seal a flushing chamber formed by the plunger and the vent wall, and pushing the flushing fluid through the vent path includes moving the plunger through the flushing chamber. 
     In Example 44, the method of any one or any combination of Examples 37-43 may include removing a frangible portion of the dispensing tip. 
     In Example 45 an apparatus may include a body including a reaction chamber including a reagent, and a solution reservoir including a solution, the solution reservoir is isolated from the reaction chamber; a plunger movably coupled with the body, movement of the plunger from a starting position to a seated position pushes the solution into the reaction chamber; a dispensing path extending from the reaction chamber and out of the body, the dispensing path is configured to dispense a reagent mixture formed from the solution and the reagent; and venting means configured to vent gas displaced by the addition of the solution to the reaction chamber. 
     In Example 46 the apparatus of Example 45 may include the venting means including a vent path extending from the reaction chamber. 
     In Example 47, the apparatus of any one or any combination of Examples 45-46 may include barrel movably coupled with the body, and the plunger is movably coupled with the barrel. 
     In Example 48, the apparatus of any one or any combination of Examples 45-47 may include the venting means extending at least partially through the barrel and along the plunger. 
     In Example 49, the apparatus of any one or any combination of Examples 45-48 may include the venting means extending along a barrel exterior through a first vent portion, and the venting means extends along a barrel interior through a second vent portion. 
     In Example 50, the apparatus of any one or any combination of Examples 45-49 may include the venting means including a semi-permeable media. 
     In Example 51, the apparatus of any one or any combination of Examples 45-50 may include a sealed dispensing path. 
     In Example 52, the apparatus of any one or any combination of Examples 45-51 may include the dispensing path sealed with a frangible tip. 
     In Example 53, the apparatus of any one or any combination of Examples 45-46 may include flushing means configured to force flushing fluid into the reaction chamber to push a specified amount of the reagent mixture through the dispensing path. 
     In Example 54, the apparatus of any one or any combination of Examples 45-53 may include the venting means extending through the flushing chamber. 
     In Example 55, the apparatus of any one or any combination of Examples 45-54 may include a second plunger operable to close the venting means, and the second plunger is operable to push the flushing fluid through the closed venting means into the reaction chamber. 
     In Example 56, the apparatus or method of any one or any combination of Examples herein is configured to form a specified volume of reagent mixture from about 10 to 100 micro liters with 10 percent or better precision. 
     In Example 57, the apparatus or method of any one or any combination of Examples herein is configured to dispense around at least 80 percent of the specified volume of the reagent mixture formed in the reaction chamber. 
     In Example 58, the apparatus or method of any one or any combination of Examples herein is configured to form a specified volume of reagent mixture from about 10 to 200 micro liters with 10 percent or better precision. 
     In Example 59, the apparatus or method of any one or any combination of Examples herein is configured to dispense at least around 90 percent of the specified volume of the reagent mixture formed in the reaction chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one example of a reagent preparation and dispensing device. 
         FIG. 2A  is a cross-sectional view of the device shown in  FIG. 1 . 
         FIG. 2B  is a detailed cross sectional view of a portion of the device shown in  FIG. 3A . 
         FIG. 3A  is a cross sectional view of the device shown in  FIG. 1 . 
         FIG. 3B  is a detailed cross sectional view of a portion of the device shown in  FIG. 3A . 
         FIG. 3C  is a cross sectional view of the device shown in  FIG. 3A  rotated to show activator lugs positioned within first barrel slots, and first plunger lugs engaged with activator stops. 
         FIG. 4A  is a cross sectional view of the device shown in  FIG. 3A  with the solution introduced to the reagent. 
         FIG. 4B  is a cross sectional view of the device shown in  FIG. 4A  rotated 90 degrees about the device longitudinal axis. 
         FIG. 4C  is a detailed cross sectional view of a portion of the device shown in  FIG. 4A . 
         FIG. 5A  is a cross sectional view of the device shown in  FIG. 3A  rotated to show the plunger lugs disengaged from the plunger stops and positioned within activator slots 
         FIG. 5B  is a cross sectional view of the device shown in  FIG. 5A  with activator lugs disengaged from barrel stops and positioned within second barrel slots. 
         FIG. 6A  is a cross sectional view of the device shown in  FIG. 3A  as the activator and a second plunger are depressed. 
         FIG. 6B  is a cross sectional view of the device shown in  FIG. 5A  rotated 90 degrees about the device longitudinal axis. 
         FIG. 7  is a cross sectional view of the device shown in  FIG. 3A  with the reagent mixture dispensed. 
         FIG. 8A  is a side view of the device shown in  FIG. 2A  in an as-supplied configuration. 
         FIG. 8B  is a side view of the device shown in  FIG. 2A  with a storage cap removed. 
         FIG. 8C  is a side view of the device shown in  FIG. 3A  with a barrel moved to open a reaction chamber including a reagent. 
         FIG. 8D  is a side view of the device shown in  FIG. 4A  with an activator and a first plunger depressed to reconstitute a reagent. 
         FIG. 8E  is a side view of the device shown in  FIG. 4A  with a frangible tip of a dispensing tip removed. 
         FIG. 8F  is a side view of the device shown in  FIG. 7  with an activator and a second plunger depressed to dispense the reagent mixture. 
         FIG. 9  is a block diagram showing one example of a method for making a reagent preparation and dispensing device. 
         FIG. 10  is a block diagram showing one example of a method for using a reagent preparation and dispensing device. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims and their equivalents. While the devices and methods presented in the detailed description describe devices for uses, non-pharmaceutical uses and the like, the devices and methods are applicable to at least some pharmaceutical applications that do not require administration to a subject by injection with a syringe needle. Additionally, the reagents described below include, but are not limited to, lyophilized reagents, liquid reagents, powder reagents and the like. Further, the solutions described below include, but are not limited to, liquid solutions such as, saline, distilled water, tap water, pH buffered water, chemical solutions capable of breaking down the reagents and the like. In another example, the solutions include, but are not limited to, biological or environmental samples in a liquid form or suspended within a liquid, such as blood, urine, fecal matter, saliva, perspiration, soil, ground water, fresh water, salt water, explosives, explosive residues, toxins and the like. 
       FIG. 1  shows one example of a reagent preparation and dispensing device  100 . As shown, the device  100  includes a body  102  movably coupled with a barrel  104 . The device  100  further includes an activator  106  movably coupled relative to the barrel  104  and the body  102 . A cap  108  is positioned over a dispensing tip coupled with the body  102 . The components of the reagent preparation and dispensing device  100  described herein are constructed with but not limited to metals, plastics and other materials capable of maintaining a dry and sterile environment within the device  100 . For instance, the reagent preparation and dispensing device  100  is constructed with stainless steel in one embodiment. In another example, the device  100  is constructed with a plastic including, but not limited to, Polypropylene, Polyethylene, Polycarbonate, Acrylic, ABS, Polystyrene, combinations of these plastics, combinations with metals and the like. While in the configuration shown in  FIG. 1 , the body  102 , barrel  104  and cap  108  cooperate to store a reagent within the reagent preparation and dispensing device  100  and substantially prevent the interaction of the reagent with moisture such as ambient humidity. In some examples, the reagent within the reagent preparation and dispensing device  100  is kept in a freeze-dried or lyophilized form and reconstitution of the reagent is performed through the addition of fluids, such as water, to the reagent. 
     Referring now to  FIG. 2A , the reagent preparation and dispensing device  100  is shown in an as-shipped configuration previously presented in  FIG. 1 . The reagent preparation and dispensing device  100  includes a solution reservoir  214  containing a solution  212  (e.g., a diluent). As shown in the example of  FIG. 2A , the solution reservoir  214  is retained within a portion of the barrel  104 . A first plunger  200  extends through the barrel  104 . In one example, the plunger  200  includes a first plunger gasket  220  positioned immediately above the solution reservoir  214 . The first plunger  200  closes the solution reservoir  214  at one end. A reservoir seal  226  is positioned across a solution nozzle  234  formed at the end of the barrel  104 , as shown in  FIG. 2B . The reservoir seal  226  closes the opposed end of the solution reservoir  214  thereby isolating the solution  212  from a reagent  204  shown in the reagent reservoir  210 . 
     The reagent reservoir  210  sized and shaped to retain the reagent  204 . As previously described, in one example, the reagent  204  includes but is not limited to a freeze-dried or lyophilized reagent capable of rapid reconstitution when introduced to a liquid, such as solution  212 . As described in further detail below, the reagent reservoir  210  includes a reaction chamber  208  as shown in  FIGS. 2A and 2B . The reaction chamber  208  is sized and shaped to receive the reagent  204  therein. During reconstitution the barrel  104  is advanced into the reagent reservoir  210  and the solution and the reagent  204  are reconstituted within the reaction chamber  208  as opposed to the entire reagent reservoir  210 . The reaction chamber  208  is in communication with a dispensing tip  206 . The dispensing tip  206  as shown in  FIGS. 2A and 2B  is sealed by a frangible tip  238 . The frangible tip  238  is sized and shaped to detach from the dispensing tip  206  when dispensing of the reconstituted reagent is desired. 
     Referring now to  FIG. 2A , the reagent preparation and dispensing device  100  includes first and second plungers  200 ,  202 . As previously described, the first plunger  200  is movably coupled with the barrel  104 . The second plunger  202  is moveably coupled around the first plunger shaft  224 . In the example shown, each of the first and second plungers  200 ,  202  includes corresponding gaskets, such as the first plunger gasket  220  and the second plunger gasket  222 . As will be described in further detail below, the first plunger gasket  220  tightly engages with the interior surface of the barrel  104  to force the solution  212  through the solution nozzle  234  and into the reaction chamber  208  when reconstitution of the reagent  204  is desired. Sliding engagement of the second plunger gasket  222  with the interior of the barrel  104  seals a portion of the barrel and forces a flushing gas through the barrel interior into the reaction chamber  208  for dispensing of the reconstituted reagent. The activator  106  is provided to actuate both the first plunger  200  and the second plunger  202 . As described in further detail below, one or more of the barrel  104 , first plunger  200  (including the first plunger shaft  224 ) and the second plunger  202  include a series of mechanical interfittings sized and shaped to selectively permit movement of one or more of the first and second plungers  200 ,  202  relative to each other and relative to the barrel  104 . Engagement of the mechanical interfittings, in some configurations, prevents movement of one or more of the first plunger  200  and second plunger  202  relative to each other or relative to the barrel  104 . 
     Referring now to  FIG. 2B , a detailed view of the reagent preparation and dispensing device  100  is shown including a piercing surface  236  of the barrel  104 . As previously described, a reservoir seal  226  is interposed between the solution reservoir  214  and the reagent reservoir  210 . Movement of the barrel  104  relative to the body  102  moves the barrel piercing surface  236  through the reservoir seal  226  to pierce the seal and allowing communication between the solution reservoir  214  and the reagent reservoir  210 . Referring to  FIG. 2A , in one example, the mechanical fitting  218  is formed between the body  102  and barrel  104 . The mechanical fitting  218  includes, but is not limited to, features that facilitate movement of the barrel  104  relative to the body  102  such as, threading, slidable couplings and the like. In the example shown in  FIGS. 2A and 2B , rotation of the barrel  104  relative to the body  102  translates the barrel  104  into engagement with the reservoir seal  226  through engagement between corresponding threading of the barrel  104  and the body  102 . As will be described in further detail below, after penetration of the reservoir seal  226  by the barrel  104  the first plunger  200  is actuated to force the solution  212  out of the solution reservoir  214  and into the reaction chamber  208  containing the reagent  204 . 
     As previously described, the reagent preparation and dispensing device  100  is configured to ensure the reagent  204  such as a freeze dried reagent is substantially isolated from moisture and fluid until reconstitution is desired. Referring to  FIG. 2B , the body  102  and dispensing tip  206  are coupled together with an interconnecting gasket  228  interposed therebetween. A crimp sleeve  230  is crimped around the interconnecting gasket  228  and adjacent portions of the body  102  and the dispensing tip  206 . In one example, the crimp sleeve  230  and the interconnecting gasket  228  are constructed with materials that substantially prevent the ingress of moisture into the reagent reservoir  210 . For instance, the interconnecting gasket  228  is formed with a non-reticulated foam, solid rubber, an elastomer, and the like. The crimp sleeve  230  is formed with a metal such as stainless steel, aluminum and the like. Crimping of the crimp sleeve  230  around the interconnecting gasket  228  substantially prevents the ingress of moisture between the reservoir seal  226  and the dispensing tip  206 . Additionally, a desiccant  216  is provided at the bottom of the cap  108  to substantially absorb any moisture present within the cap  108  at the assembly of the reagent preparation and dispensing device  100 , during transport and immediately prior to use. In yet another example, the cap  108  is constructed with metal, such as stainless steel or aluminum, configured to substantially prevent the ingress of moisture through the cap. Further, as shown in  FIGS. 2A and 2B  the dispensing tip  206  includes a frangible tip  238  coupled thereto. The frangible tip provides a sealed feature on the dispensing tip  206  to substantially prevent the ingress of moisture and fluids into the reagent reservoir  210  through the dispensing path used after reconstitution to dispense the reconstituted reagent from the device  100  (e.g., the lumen from the reaction chamber  208  to exterior of the device  100 ). 
       FIGS. 3A and 3B  show the reagent preparation and dispensing device  100  in a first intermediate configuration. As previously described, the barrel  104  is movable relative to the body  102 . Referring first to  FIG. 3A , the barrel  104  is translated relative to body  102  with the barrel piercing surface  236  penetrating through the reservoir seal  226  (see  FIGS. 2A and 2B ). Penetration of the reservoir seal  226  allows for communication between the solution reservoir  214  and the reaction chamber  208  containing the reagent  204 . Movement of the activator and the first plunger  200  relative to the barrel  104  as described below pushes the solution  212  in the solution reservoir  214  through the solution nozzle  234  into the reaction chamber  208 . The addition of the solution  212  to the reaction chamber  208  reconstitutes the reagent  204  into a reagent mixture for eventual dispensing through the dispensing tip  206 . 
     Movement of the barrel  104  including the piercing surface  236  into the reagent reservoir  210  (see  FIGS. 2A and 2B ) fills a portion of the reagent reservoir  210  thereby leaving the reagent  204  within the reaction chamber  208  for interaction with the solution  212  from the solution reservoir  214 . The barrel is sized and shaped for reception within the reagent reservoir  210  and seating therein to define the reaction chamber  208  as shown in  FIGS. 3A and 3B . For instance, the barrel includes the piercing surface  236  and the dispensing tip  206  includes a second barrel stop  302  sized and shaped to engage with the piercing surface  236  and receive the piercing surface after full translation of the barrel  104  into the selected region of the reagent reservoir  210  as shown in  FIGS. 3A and 3B . Engagement of the second barrel stop  302  with the piercing surface  236  arrests further movement of the barrel  104  thereby maintaining a specified volume within the reaction chamber  208  for reconstitution of the reagent  204 . 
     In another example, the reagent preparation and dispensing device  100  includes a first barrel stop  300  included with the body  102 . A First barrel flange  304  on the body  104  is sized and shaped to engage with the first barrel stop  302  and arrest further movement of the barrel  104  into the body  102 . In a similar manner to the second barrel stop  302  and the piercing surface  236 , the first barrel stop  300  and first barrel flange  304  arrest movement of the piercing surface  236  thereby maintaining a consistent volume in the reaction chamber  208  for reconstitution of the reagent  204 . As previously described in at least one example, a mechanical fitting  218  is formed between the body  102  and the barrel  104 . In one example, rotation of the barrel  104  relative to the body  102  longitudinally moves the barrel  104  into the body  102 , for instance, penetrating the piercing surface  236  through the reservoir seal  226  to facilitate reconstitution of the reagent  204 . As the barrel  104  is rotated relative to the body  102  the first barrel flange  304  at one end of the threading of the mechanical fitting  218  engages against the first barrel stop  300  to arrest further movement of the barrel  104  through rotation into the body  102 . Seating of the barrel within the reagent reservoir  210  shrinks the reservoir to include only the reaction chamber  208  and ensures the solution  212  interacts with the reagent  204  in the smaller space. Unintended separation of the solution  212  from the reagent  204  is thereby avoided. 
     The barrel further includes a vent flange  306  sized and shaped to engage with the interconnecting gasket  228 . Engagement of the vent flange  306  with the interconnecting gasket  228  tightly seals the portion of the barrel extending from the vent flange  306  to the piercing surface  236 . As will be described in further detail below, engagement of the vent flange  306  with the interconnecting gasket  328  forms a sealed passage for venting of gases from the reaction chamber  208  during reconstitution of the reagent  204 . Referring to  FIG. 3A , in one example, the first barrel stop, second barrel stop  300 ,  302  and the first barrel flange  304  and piercing surface  236  of the barrel  104 , dispensing tip  206  and body  102  are sized and shaped to position the barrel  104  after movement into the body  102  so the vent flange  306  tightly engages with the interconnecting gasket  228  to form the seal therebetween. Stated another way, as the first barrel flange  304  engages with the first barrel stop  300  and the piercing surface  236  correspondingly engages with the second barrel stop  302  the vent flange  306  is engaged with and seals against the interconnecting gasket  228  to form a sealed vent path. 
       FIG. 3C  shows another view of the reagent preparation and dispensing device  100  previously shown in  FIGS. 3A and 3B . The view shown in  FIG. 3C  is rotated relative to those of  FIGS. 3A , B to illustrate differing features, as describe below. As previously described the barrel  104  is advanced into the body  102  to pierce a reservoir seal  226  shown in  FIG. 2A . As will be described in further detail below, depression of the activator  106  while the reagent preparation and dispensing device  100  is in the configuration shown in  FIG. 3C  correspondingly moves the first plunger  200  through the solution reservoir  214  thereby pushing the solution  212  into the reaction chamber  208  containing the reagent  204 . As shown in  FIG. 3C , a series of lugs, slots and stops are selectively engaged to fix the activator  106  relative to the first plunger  200  so that depression of the activator  106  correspondingly moves the first plunger  200 . For instance, the first plunger  200  includes plunger lugs  312  sized and shaped for engagement with activator stops  314  formed in the activator  106  (e.g., near an end of the second plunger  202 ). Selective engagement of the activator stops  314  and the plunger lugs  312  transmits longitudinal movement from the activator  106  to the first plunger  200  to thereby push the solution  212  out of the solution reservoir  214  for reconstitution of the reagent  204 . 
     In yet another example, the activator  106  includes activator lugs  308  sized and shaped for reception within first barrel slots  310  of the barrel  104 . While the activator lugs  308  are received within the first barrel slots  310  the activator  106  and the first plunger  200  selectively engaged with the activator are longitudinally movable relative to the barrel  104 . Stated another way, the activator lugs  308  are slidably received within the first barrel slots  310  to facilitate longitudinal movement of the activator  106  and first plunger  200  relative to the barrel  104 . As will be described in further detail below, the activator lugs  308  and plunger lugs  312  are respectively positionable within the corresponding barrel slots  310  and engaged with the activator stops  314  to lock and unlock the activator  106  relative to the barrel  104  and also selectively engage and disengage the first plunger  200  from the activator  106 . By selectively engaging and disengaging the barrel  104 , the activator  106  and the first plunger  200 , relative movement between these components is permitted or prevented at various steps during reconstitution and dispensing of the reagent solution through the dispensing tip  206 . 
       FIGS. 4A-C  show the reagent preparation and dispensing device  100  in a second intermediate configuration. As shown in  FIG. 4A , the activator  106  is moved relative to the barrel  104  and body  102  to position the plunger  200  in the orientation shown in  FIG. 4A . As will be described in further detail below, the activator  106  is engaged with the plunger  200  and longitudinal movement of the activator  106  is transmitted to the plunger  200 . As shown in  FIG. 4A , the activator  106 , in one example, is integral to the second plunger  202 . When moved the activator  106 , the second plunger  202  and the first plunger  200  move as a single assembly while the activator  106  is longitudinally fixed relative to the first plunger  200 . Referring back to  FIG. 2A , the activator  106  and the first plunger  200  are shown in a starting position where the first plunger  200  and the first plunger gasket  220  are positioned at one end of the solution reservoir  214  and the solution  212  is retained within the reservoir. After translation of the barrel  104  relative to the body  102 , the activator  106 , second plunger  202  and first plunger  200  along with the solution reservoir  214  are translated into the dispensing tip  206  (e.g., the reagent reservoir  210 ). While in the orientation shown in  FIG. 3A , the activator  106  and first plunger  200  are held statically relative to the body  104  and the solution  212  is not forced out of the solution reservoir  214 . Stated another way the plunger  200  remains in the starting position shown in  FIG. 2A  while the barrel  104  is advanced into the reagent reservoir  210  and the reservoir seal  226  shown in  FIG. 2B  is penetrated. 
     Referring again to  FIG. 4A , the first plunger  200  is moved relative to the body  104  by the activator  106 , for instance, the technician depresses the activator  106  to move the first plunger  200  into the seated position shown in  FIG. 4A . As the first plunger  200  is advanced through the solution reservoir  214  the solution  212  is pushed into the reaction chamber  208 . Movement of the first plunger  200  from the starting position shown in  FIGS. 2A, 3A  to the seated position shown in  FIG. 4A  forces the entirety of the solution  212  through the solution nozzle  234  shown in  FIGS. 2A and 2B  (and  4 C). The solution reservoir  214  is thereby substantially eliminated to prevent retention of the solution  212  therein. Introduction of the solution into the reaction chamber  208  reconstitutes the reagent  204  forming a reagent mixture  400  (e.g., a reagent solution or reconstituted reagent). 
     Referring now to  FIG. 4C , the first plunger  200  is advanced to push the entirety of the solution into the reaction chamber  208  as described above. As shown, the plunger includes a plunger flange  402  sized and shaped to engage with the plunger seat  404  when the plunger  200  reaches the seated position shown in  FIG. 4C . Engagement of the plunger flange  402  (e.g., a part of the first plunger gasket  220 ) with the plunger seat  404  provides affirmative notification to the technician using the reagent preparation and dispensing device  100  that the entirety of the solution has been transmitted to the reaction chamber  208  for reconstitution of the reagent  204 . Residual solution within the solution reservoir  214  (and not used in reconstitution) is thereby avoided. In another example, where the plunger  200  includes the first plunger gasket  220 , the first plunger gasket wipes any remaining solution from the interior of the solution reservoir  214  and forces it through the solution nozzle  234  interposed between the solution reservoir  214  and reaction chamber  208 . After actuation of the activator  106  and the first plunger  200  into the seated position shown in  FIGS. 4A-C , because of the affirmative seating of the first plunger  200  as shown it is clear to the technician that the entirety of the solution has been added to the reaction chamber  208 . 
     With the features described herein, for instance the shrinking of the reaction chamber  208 , seating of the plunger  200  at the plunger seat  404  to substantially eliminate the solution reservoir  214  and the like, consistent and reliable reconstitution of relatively small volumes of reagent is achieved (i.e., at the micro liter scale). In one example, the reagent preparation and dispensing device  100  is configured to reconstitute a specified volume of reagent between around 10 to 300 micro liters (e.g., the device  100  is configured to reconstitute one of 10, 20, 100, 200 or 300 and the like micro liters of reagent). In another example, the reagent preparation and dispensing device is configured to reconstitute between around 10 to 200 micro liters. In still another example, the reagent preparation and dispensing device  100  is configured to reconstitute between around 10 to 100 micro liters. Because of the precise construction of the device  100  with the previously described features and functions including, but not limited to, shrinking of the reaction chamber  208 , seating of the plunger  200  at the plunger seat  404  and the like the device is able to reconstitute a specified amount of reagent with 10 percent or better (e.g., 5 percent) precision. Stated another way, for a reagent preparation and dispensing device  100  configured to reconstitute 10 micro liters the device  100  is able to reconstitute the reagent with precision near plus or minus 1 micro liter (around a fortieth of a drop). In another example, the device  100  is configured to reconstitute 10 micro liters of a reagent with 5 percent precision, for instance plus or minus 0.5 micro liters or around eightieth of a drop). 
     Referring to  FIG. 4B , addition of the solution  212  to the reaction chamber  208  to form the reagent solution by movement of the activator  106  and first plunger  200  displaces the gas in the reaction chamber  208  present before reconstitution of the reagent  204 . The frangible tip  238  is coupled with the dispensing tip as previously described above. The frangible tip  238  allows for reconstitution of the reagent  204  within the reaction chamber  208  without undesirable dispensing of the partially reconstituted reagent. Provision of the frangible tip  238  further seals the reaction chamber  208  and prevents the release of gas through the dispensing tip  206  displaced by the addition of the solution  212 . 
     A venting means including a vent path  408  is provided within the reagent preparation and dispensing device  100  to vent the gas displaced from the reaction chamber  208 . The vent path  408  permits the displaced gas from the reaction chamber  208  to escape from the reaction chamber and exit the reagent preparation and dispensing device  100  without developing an overpressure within the reaction chamber that could prematurely dispense the reconstituted reagent through fracture of the frangible tip  238 . Stated another way, pressurizing of the reaction chamber  208  is prevented by the vent path  408 . As shown in the example provided in  FIG. 4B , the vent path  408  extends through the reagent preparation and dispensing device  100  in a direction opposed to the frangible tip  238  and the dispensing tip  206  sized and shaped to pass the reconstituted reagent therethrough. By extending the vent path  408  in an opposed direction the reagent preparation and dispensing device  100  may be maintained in the substantially vertical orientation shown throughout operation of the device  100  to thereby allow the technician to simply operate the activator  106  without having to adjust the orientation of the reagent preparation and dispensing device  100  to ensure proper venting of the gas from the reaction chamber  208  while reconstituting the reagent  204 . The venting means described herein includes the vent path  408  separately or together with the components of the device  100  forming the vent path. Optionally, the venting means includes one or more of the device components described herein forming the vent path  408 . 
     Referring now to  FIG. 4B , the vent path  408  begins in the reaction chamber  208  and extends through reaction chamber vents  410  formed in the dispensing tip  206 . The vent path  408  extends from the reaction chamber vents  410  through the space formed between the barrel  104  and the dispensing tip  206 . As shown in  FIG. 4B , the vent path  408  continues along the dispensing tip  206  through the interconnecting gasket  228  to barrel passages  412  extending through the barrel  104  and into the barrel interior. Two barrel passages  412  are shown in  FIG. 4B  that extend through the barrel  104 . In another example, one or more barrel passages extend through the barrel allowing the gas displaced from the reaction chamber  208  to vent from the reagent preparation and dispensing device  100  during addition of the solution  212  to the reaction chamber. For instance, as previously described,  FIGS. 4A and 4B  show two views of the reagent preparation and dispensing device  100 . The view in  4 B is rotated relative to the view in  4 A and both views include barrel passages  412 . By providing a plurality of barrel passages  412  through the barrel  104  gas displaced by the addition of the solution  212  to the reaction chamber  208  is easily able to pass through the barrel  104  and continue along the vent path  408 . 
     In one example, as previously shown in  FIG. 3B , the vent flange  306  engages with the interconnecting gasket  228  and substantially seals the vent path  408  from the reaction chamber  208  to the barrel passages  412 . Sealing of the vent flange  306  at the interconnecting gasket  228  thereby substantially prevents the movement of gas displaced from the reaction chamber  208  into the region between the barrel  104  and body  102  and instead diverts the gas through the barrel passages  412  along the remainder of the vent path  408  where the gas can escape from the reagent preparation and dispensing device  100 . Referring to  FIG. 4C , In another example, a semi-permeable membrane  414  is positioned within the vent path  408 . Optionally, the semi-permeable membrane  414  is positioned over the barrel passages  412  (e.g., on one or more of the interior or exterior of the barrel  104 ). The semi-permeable membrane  414  is configured to prevent the movement of the reagent mixture  400  from out of the device  100  through the vent path  408 . For instance, the semi-permeable membrane  414  includes, but is not limited to, a hydrophobic membrane that permits the passage of gas, such as displaced gas from the reaction chamber  208  but prevents the passage of the reagent mixture  400 . The reagent preparation and dispensing device  100  is thereby configured to retain the reagent mixture  400  within the device until dispensing of the mixture is desired while minimizing leaks of the mixture through the gas vent path  408 . Optionally, the semi-permeable membrane  414  includes, but is not limited to, a lipophobic membrane, other membranes that facilitate passage of the flushing fluid and block passage of the reagent mixture, a suitable combination of membranes (e.g., lipophobic and hydrophobic) and the like. 
     Referring again to  FIG. 4B , after passing through the barrel passages  412 , the displaced gas moves through the barrel  104  and the space between the barrel interior and the first plunger  200 . Because the second plunger gasket  222  is disengaged from the interior of the barrel  104  the vent path  408  continues uninterrupted along the second plunger  202  in between the activator  106  and the barrel  104 . As previously described above, the activator  106  includes activator lugs  308  sized and shaped to engage with barrel stop  406  and slidably move within the first barrel slots  310  (and second barrel slots described below). The activator lugs  308  extend around only a portion of the activator  106  thereby allowing the gas vented along the vent path  408  to divert around the activator lungs  308  and continue on between the activator  106  and body  104  (e.g., for instance through the first barrel slots  310 ) to exit the reagent preparation and dispensing device  100 . 
     The vent path  408  thereby provides for equalization of pressure within the reaction chamber  208  during reconstitution of the reagent  204  therein. The solution  212  is able to freely move into the reaction chamber  208  because the vent path  408  remains open throughout movement of the first plunger  200  relative to the barrel  104 . Stated another way, because the vent path  408  remains open from a starting position of the first plunger  200  shown in  FIG. 3B  to a seated position shown in  FIG. 4B  gas displaced by the addition of the solution into the reaction chamber  208  is continuously vented from the reagent preparation and dispensing device  100  without pressurizing the reaction chamber  208 . The solution  212  is thereby added to the reaction chamber  208  without any resistance from pressure developed within the reaction chamber  208 . Further, the technician is able to perform the entire movement of the first plunger  200  to add the solution  212  to the reaction chamber  208  while maintaining the reaction preparation and dispensing device  100  in a single vertical orientation throughout reconstituting of the reagent  204 . 
     Further still, referring again to  FIG. 3B , because the first plunger gasket  220  is positioned below the barrel passages  412  the vent path  408  remains open throughout the entire movement of the first plunger  200  relative to the barrel  104 . The vent path  408  is substantially isolated from the solution reservoir  214  and the reaction chamber  208  and only in communication with the reaction chamber  208  through the reaction chamber vents  410 . The first plunger  200  is thereby able to freely translate from the position in  FIG. 3B  to the seated position shown in  FIG. 4B  thereby moving the entirety of the solution  212  into the reaction chamber  208  while venting displaced gas through the vent path  408 . In contrast, if a vent was provided within the solution reservoir  214 , after passage of the first plunger  200  past the vent, such a vent would be closed and gas displaced from the reaction chamber  208  would no longer be vented. The vent path  408  addresses this issue by providing an entirely separate path from the solution reservoir  214  throughout the entirety of the movement of the first plunger  200 . As discussed above, gas displaced from the reaction chamber  208  by the addition of the solution  212  is thereby readily vented through the vent path  408  without pressurizing the reaction chamber  208 . 
     As described above, the reagent preparation and dispensing device  100  is configured to consistently reconstitute precise small volumes of reagent (e.g., between 10 and 300 microliters with around 5 to 10 percent precision). The vent path  408  further facilitates the precise reconstitution of the reagent  204  at these volumes. By venting gas within the reaction chamber  208  as solution  212  is added back pressure is eliminated throughout the movement of the first plunger  200  and the full solution volume is delivered to the reaction chamber. Providing the vent path  408  ensures the first plunger  200  fully seats on the plunger seat  404  and substantially all of the solution  212  is correspondingly delivered from the solution reservoir  214  to the reaction chamber. Back pressure acting against the movement of the first plunger  200  is thereby eliminated. Further still, the vent path  408  substantially prevents the escape of the reconstituted reagent mixture  400 , for instance through the vent path, because the vent path extends out of the top of the reaction chamber  208  relative to the dispensing tip  206  and the reagent is reconstituted at the bottom of the reaction chamber near the tip. Flipping of the reagent preparation and dispensing device  100  to reconstitute the reagent (for instance where gas is vented through the dispensing tip) is thereby avoided and the risk of a portion of the reagent mixture prematurely exiting through an orifice, such as the dispensing tip  206  is substantially avoided. In another example, The vent path  408  includes a semi-permeable membrane that further prevents unintended delivery of a portion of the reagent mixture  400  through the vent path prior to a desired delivery through the dispensing tip  206 . 
       FIGS. 5A and 5B  show the reagent preparation and dispensing device  100  between the configurations shown in  FIGS. 4A-C  and  FIGS. 6A , B (described below). Relative to  FIGS. 4A-C  the activator  106  of the reagent preparation and dispensing device  100  is rotated relative to the barrel  104  and the first plunger  200 . As was previously shown and described in  FIGS. 3A-C , engagement of the plunger lugs  312  with the activator stops  314  of the first plunger  200  and the activator  106 , respectively, allows for the transmission of movement from the activator  106  to the plunger  200  for pushing of the solution  212  into the reaction chamber  208 . After the addition of the solution  212  to the reaction chamber  208  for reconstitution of the reagent  204 , the first plunger  200  including the first plunger gasket  220  is seated in the orientation shown in  FIGS. 5A and 5B  (as well as  FIGS. 4A-C ). Further movement of the first plunger  200  is arrested by the engagement of the activator lugs  308  with the barrel stop  406  and engagement of the plunger flange  402  with the plunger seat  404 . After the addition of the solution  212  to form the reagent mixture  400 , additional movement of the activator  106  is needed to dispense the reagent mixture from the reagent preparation and dispensing device  100 . To facilitate movement of the activator  106  relative to the seated first plunger  200 , the activator  106  is rotated relative to the first plunger  200  as well as the barrel  104 . Rotation of the activator  106  moves the activator stops  314  out of phase with the plunger lugs  312 . As shown in  FIG. 5A , the plunger lugs  312  are positioned within plunger slots  500  of the activator  106  (and the second plunger  202 ). 
     Referring now to  FIG. 5B , rotation of the activator  106  relative to the barrel  104  also positions the activator lugs  308  out of phase with the barrel stop  406  shown in  FIG. 5A . The activator lugs  308  are instead positioned in second barrel slots  502  extending toward the dispensing tip  206  to allow for additional movement of the activator  106  relative to the barrel  104 . Referring to both  FIGS. 5A and 5B , disengagement of the plunger lugs  312  and activator lugs  308  frees the activator  106 , including the second plunger  202 , to move relative to the barrel  104  and the first plunger  200 . As will be described in further detail below, movement of the activator  106  and the second plunger  202  relative to the first plunger  200  and the barrel  104  closes the vent path  408  and forms a flushing fluid chamber within the reagent preparation and dispensing device  100 . Further, movement of the activator  106  and the second plunger  202  moves flushing fluid from the flushing gas chamber into the reaction chamber  208  for dispensing of the reagent mixture  400  through the dispensing tip  206 . 
       FIGS. 6A and 6B  show the reagent preparation and dispensing device  100  as the activator  106  and the second plunger  202  are transitioning from the orientation shown in  FIGS. 4A-C  to a fully dispensed configuration shown in  FIG. 7 . As previously described, with the activator  106  rotated relative to the first plunger  200  and the barrel  104  the activator  106  and the second plunger  202  are movable relative to these features to dispense the reagent mixture  400  from the dispensing tip  206 . As shown in  FIG. 6A , for example, the activator lugs  308  are positioned within the second barrel slots  502 , and as shown in  FIG. 5A  the plunger lugs  312  are slidably received within the plunger slots  500  thereby permitting the second plunger  200  and the activator  106  to slide along the first plunger  200 . As the second plunger  202  is advanced along the first plunger  200  the second plunger gasket  222  engages with a barrel inner wall  604 . Engagement of the second plunger  202  including the second plunger gasket  222  with the barrel inner wall  604  (e.g., a vent wall) seals the vent path  408  shown in  FIGS. 4A-C  and prevents the continued flow of gas from the reaction chamber  208  through the vent path  408 . With the vent path  408  in this closed configuration, a flushing fluid chamber  600  (a flushing means or part of a flushing means) is formed by the second plunger  202  and the barrel  104 . Continuing movement of the activator  106  and the second plunger  202  pressurizes the reaction chamber  208  and pushes a flushing fluid, such as air, through the flushing fluid chamber  600  and into the reaction chamber  208  for dispensing of the reagent mixture  400  through the dispensing tip  206 . As shown in  FIGS. 6A , B, because the device  100  is oriented vertically during reconstitution the reagent mixture  400  settles into the funnel of the reaction chamber  208  adjacent to the dispensing tip  206 . The flushing fluid delivered to the reaction chamber at the opposed end from the tip  206  thereby flushes the reagent mixture  400  through the funneled reaction chamber and out of the tip. 
     Referring first to  FIG. 6A , the flushing fluid chamber  600  is shown in communication with the reaction chamber  208  through a flushing path  602  extending therebetween. The flushing means described herein includes one or more of the flushing path  602 , the vent path  408 , the flushing fluid chamber  600  separately or together. Optionally, the flushing means includes one or more of the device  100  components described herein forming the vent path  602  and the flushing fluid chamber  600 . 
     The flushing path  602  in the example shown in  FIGS. 6A and 6B  uses the same route as the vent path  408  previously described (e.g., the vent path extends through the flushing fluid chamber  600 ). For instance, the flushing path  602  begins at the flushing fluid chamber  600  and extends through the barrel passages  412  formed in the barrel  104 . The flushing path  602  extends along the barrel  104  and the interconnecting gasket  228  as well as the dispensing tip  206  on its way toward the reaction chamber  208 . Referring next to  FIG. 6B , the flushing path  602  continues along the barrel  104  and extends into the reaction chamber  208  through the reaction chamber vents  410 . Movement of the flushing fluid into the reaction chamber  208  along the flushing path  602  correspondingly pushes the reagent mixture  400  through the dispensing tip  206  and allows for complete dispensing of the reagent mixture from the reagent preparation and dispensing device  100 . 
     In one example, as with the vent path  408 , described above, the engagement of the vent flange  306  with the interconnecting gasket  228  ensures the flushing fluid moving from the flushing fluid chamber  600  through the flushing path  602  is directed toward the reaction chamber  208  during movement of the second plunger  202 . Stated another way, the engagement of the vent flange  306  with the interconnecting gasket  228  seals the flushing path  602  thereby preventing leaks of flushing fluid and ensuring the flushing fluid is transmitted directly to the reaction chamber  208  for dispensing of the reagent mixture  400 . 
     Actual physical engagement between the second plunger  208  and the reagent mixture  400  is not needed to dispense the reagent mixture from the reagent preparation and dispensing device  100 . Instead, the flushing fluid chamber  600  includes a sufficient amount of flushing gas (or another fluid configured for flushing the reagent mixture  400 ) through the dimensioning of the volume of the chamber to enable the full dispensing of the reagent mixture  400  through the depression of the activator  106  and corresponding movement of flushing fluid through the flushing passage  602  into the reaction chamber  208 . In one example, the flushing fluid chamber  600  has a volume greater than the volume of the reaction chamber  208 . The larger volume of the flushing fluid chamber  600  ensures a correspondingly large volume of flushing fluid is pushed into the reaction chamber  208  to fully dispense the reagent mixture  400  from the dispensing tip  206 . Stated another way, the relatively large volume of flushing fluid within the flushing fluid chamber  600  continues to stream into the reaction chamber  208  throughout the movement of the second plunger  202  thereby ensuring the reagent mixture  400  is flushed out of the dispensing tip  206  with a relatively larger volume of fluid. Because physical engagement between the second plunger and  202  and the reagent mixture  400  is not used to dispense the mixture from the dispensing tip  206 , movement of the second plunger  202  through a larger volume (e.g., the volume of the flushing fluid chamber  600 ) is thereby able to push a correspondingly larger volume of fluid into the relatively small reaction chamber  208  to ensure the complete dispensing of the reagent mixture  400  through the dispensing tip  206 . By using the larger volume of flushing from the flushing fluid chamber  600  the entire amount of the reconstituted reagent mixtures is thereby dispensed, and remaining reagent residue on the interior of the dispensing tip  206  is substantially prevented. 
     The combination of features described herein, including but not limited to shrinking of the reaction chamber  208 , seating of the first plunger  200  at the plunger seat  404  to substantially eliminate the solution reservoir  214 , provision of the vent path  408  and the like ensure the consistent and precise reconstitution of the reagent mixture at micro liter scale volumes (e.g., from 10 to 300 microliters). The flushing fluid chamber  600  and the flushing passage  602  (including in one example the vent path  408 ) cooperate with these previously described features to ensure substantially all of the reconstituted reagent mixture  400  is dispensed from the device  100 . In one example, the flushing fluid chamber  600  and the flushing passage  602  alone or in combination with the other recited features described herein ensure around 80 percent of the reconstituted reagent mixture  400  is precisely and consistently dispensed from the device  100  (e.g., 80 percent or better of a quarter of a drop or 10 micro liters). In another example, the flushing fluid chamber  600  and the flushing passage  602  alone or in combination with the other recited features described herein ensure around 90 percent of the reconstituted reagent mixture  400  is precisely and consistently dispensed from the device  100 . These features and functions mitigate the need in other devices to reconstitute large volumes of reagent, for instance 300 micro liters, a milliliter or more, and then dispense only a specified portion of the reconstituted reagent. Many reagents are costly and the reconstitution of large volumes of the reagent and subsequent dispensing of only a portion of the reagent makes these other devices cost prohibitive and impractical. The reagent preparation and dispensing device  100  reconstitutes only the amount of reagent needed (e.g., expensive reagents or reagents with short shelf lives) for the particular application at a micro liter scale and is able to deliver substantially all of the reconstituted reagent. 
       FIG. 7  shows the reagent preparation and dispensing device  100  in the fully dispensed configuration with the activator  106  and the second plunger  202  fully received within the barrel  104  and the reagent mixture  400  is dispensed from the dispensing tip  206 . As previously described above, movement of the activator  106  and the second plunger  202  relative to the barrel  104  forces fluid within the flushing fluid chamber  600  through the flushing path  602  into the reaction chamber  208  to dispense the reagent mixture  400 . When the flushing fluid is fully moved out of the flushing fluid chamber  600  the second plunger  202  including the second plunger gasket  222  is fully seated within the barrel  104  as shown in  FIG. 7 . For instance, the second plunger gasket  222  is engaged with a second plunger seat  700 . In another example, a first activator flange  704  at an opposed end of the activator  106  from the second plunger  202  is engaged against a second barrel stop  702  formed in the barrel  104 . In still another example, the reagent preparation and dispensing device  100  includes a second activator flange  706  on the activator  106 . The second activator flange  706  is sized and shaped to engage with the second barrel stop  708  on the barrel  104  after the activator  106  is fully moved to force the flushing fluid into the reaction chamber  208 . The barrel  104 , the activator  106  and the second plunger  202  are sized and shaped to ensure that full movement of the activator  106  and second plunger  202  into the barrel  104  fully pushes the volume of flushing fluid within the flushing fluid chamber  600  into the reaction chamber  208 . After engagement of the second plunger gasket  222 , the first activator flange  704  and the second activator flange  706  with corresponding stops and seats  700 ,  702 ,  708  the technician is affirmatively aware the reagent mixture  400  is fully dispensed from the reagent preparation and dispensing device  100  because the activator  106  is fully engaged and further movement of the activator  106  into the device  100  is substantially prevented. By tactile sensation, e.g., arresting of further movement, the technician is confident that the full amount of the reagent mixture  400  is dispensed from the reagent preparation and dispensing device. 
       FIGS. 8A through 8F  show the reagent preparation and dispensing device  100  in the configurations for reconstitution and dispensing of a reagent mixture as previously described and shown in  FIGS. 2A through 7 . Referring first to  FIG. 8A , the reagent preparation and dispensing device  100  is shown in a starting orientation with the activator  106  extending out of the barrel  104  and the barrel  104  is rotatably coupled with the body  102 . In the starting orientation the barrel  104  is in this orientation with a reservoir seal  226  interposed between the reagent reservoir  210  and the solution reservoir  214  (see  FIG. 2A ). A dispensing tip  206  including the reagent reservoir  210  having the reagent  204  therein is held within a cap  108 . The cap  108  includes, in one example, a desiccant  216  that cooperates with the frangible tip  238  to substantially prevent the ingress of moisture into the reagent reservoir  210 . Undesired reconstitution of the reagent  204  prior to piercing of the reservoir seal  226  is thereby prevented. 
     Referring now to  FIG. 8B , the cap  108  is removed exposing the dispensing tip  206  and the frangible tip  238  of the reagent preparation and dispensing device  100 . As shown, the activator  106  remains in the starting orientation as does the barrel  104  relative to the body  102 . In another example, the cap  108  remains on the dispensing tip  206  throughout reconstitution until removal of the frangible tip  238  is required for dispensing. 
       FIG. 8C  shows the reagent preparation and dispensing device  100  in a first intermediate configuration. The barrel  104  is moved relative to the body  102  as shown in  FIGS. 3A-C . Movement of the barrel  104  relative to the body  102  moves the piercing surface  236  of the barrel  104  through the reservoir seal  226  (see  FIG. 2A ). Piercing of the reservoir seal  226  allows the solution reservoir  214  to communicate with the reaction chamber  208  including the reagent  204 . As previously described, movement of the barrel  104  fills the space within the reagent reservoir  210  leaving the reaction chamber  208  with a smaller volume with the reagent  204  therein. 
     Referring again to  FIG. 8C , the reagent preparation and dispensing device  100 , in one example, includes a mechanical fitting  218  sized and shaped to translate rotation of the barrel  104  into longitudinal movement of the barrel relative to the body  102 . For instance, in one example, a mechanical fitting  218  includes threading on the opposed surfaces of the barrel  104  and the body  102 . Rotation of the barrel  104  thereby longitudinally moves the barrel  104  into the body  102 . The piercing surface  236 , as previously described, is driven through the reservoir seal  226 . In other examples, the barrel  104  is slidably coupled with the body  102  and the mechanical fitting  218  facilitates the slidable coupling therebetween. Longitudinal movement of the barrel  104 , for instance, by depression from the user is used to move the piercing surface  236  through the reservoir seal  226 . 
     Referring now to  FIG. 8D , the reagent preparation and dispensing device  100  is shown in a second intermediate configuration with the activator  106  depressed relative to the orientation shown in  FIG. 8C . The activator  106  is depressed at least partially into the barrel  104 . As shown in  FIGS. 4A-C , movement of the activator  106  drives the first plunger  200  through the barrel  104 . Movement of the first plunger  200  correspondingly moves the solution  212  out of the solution reservoir  214  (see  FIGS. 3A-C ) and into the reaction chamber  208  containing the reagent  204 . Movement of the first plunger  200  thereby reconstitutes the reagent  204  by adding the solution  212  to the reagent  204 . Addition of the solution to the reagent  204  forms the reagent mixture  400  shown in  FIGS. 4A-C . As shown in  FIGS. 4B and 4C , the activator  106  and the first plunger  200  move as an assembly into the configuration shown in  FIGS. 4B and 4C  until the plunger flange  402  of the first plunger  200  engages with and seats on the plunger seat  404 . Further, in another example, movement of the activator  106  and first plunger  200  is also arrested by engagement of activator lugs  308  with a barrel stop  406  formed in the barrel  104 . Engagement of these features provides an affirmative notification to the technician that the solution  212  previously in the solution reservoir  214  is fully dispensed into the reaction chamber  208  by movement of the activator  106 . Stated another way, as the activator  106  is engaged against the features within the barrel, including the barrel stop  406  and the plunger flange  402 , the first plunger  200  has moved through the entirety of the solution reservoir  214  and has thereby fully dispensed the solution  212  into the reaction chamber  208  for reconstitution. 
     As shown in  FIG. 8E , the frangible tip  238  is removed from the dispensing tip  206  in preparation for dispensing of the reagent mixture  400  from the device  100 . In the example shown, the activator  106  is rotated relative to the barrel  104 . As previously described and shown in  FIGS. 6A , B, rotation of the activator  106  positions the activator lugs  308  within the second barrel slots  502 . Positioning the activator lugs  308  within the second barrel slots  502  permits further longitudinal movement of the activator  106  relative to the barrel  104  and the body  102 . Additionally, rotation of the activator  106  disengages the plunger lugs  312  from the activator stops  314  and positions the lugs within the plunger slots  500 . The activator  106  is thereby unlocked from the first plunger  200  and configured for longitudinal movement relative to the first plunger  200  as well as the barrel  104 . In the configuration shown in  FIGS. 6A , B and  8 E, continued longitudinal movement of the activator  106  relative to the barrel  104  dispenses the reagent mixture, as described above and further described below. 
     Once the frangible tip  238  is removed from the dispensing tip  206  the reagent preparation and dispensing device  100  is in a configuration ready to dispense the reagent mixture  400 . Referring to  FIG. 8F , the reagent preparation and dispensing device  100  is shown in a dispensing configuration with the activator  106  depressed relative to the barrel  104 . As shown, the activator  106  is moved from a configuration shown in  FIG. 8E  to that shown in  8 F. Referring to  FIGS. 6A and 6B , the reagent preparation and dispensing device  100  is shown in a configuration with the activator  106  between the orientations shown in  FIGS. 8E and 8F . The activator  106  is moved into the barrel  104  relative to the barrel  104  and the first plunger  200 . The second plunger  202  including the second plunger gasket  222  is engaged with the barrel inner wall  604 . Engagement of the second plunger  202  (including, in one example, the second plunger gasket  222 ) with the barrel inner wall  604  seals the vent path  408  and prevents the venting of gases from the reaction chamber  208  out of the reagent preparation and dispensing device  100 . In contrast, the vent path  408  is shown in the preceding open configuration in  FIGS. 4A , B. 
     Once the vent path  408  is closed by the engagement of the second plunger  202  with the barrel  104  a flushing fluid chamber  600  is formed. As shown in  FIGS. 6A and 6B , the flushing fluid chamber  600  is formed by the second plunger  202  engaged with the barrel inner wall  604 . The flushing fluid chamber  600  communicates with the reaction chamber  208  through the flushing path  602 . As shown in  FIG. 6A , the flushing path  602  travels through the reagent preparation and dispensing device  100  in a similar manner to the vent path  408  shown in  FIG. 5B . For instance, the flushing path  602  extends through the barrel passages  412  along the barrel  104  between the interconnecting gasket  228 . The flushing path  602  extends into the reaction chamber  208  through the reaction chamber vents  410  positioned around at least a portion of the dispensing tip  206 . As the activator  106  including the second plunger  202  is moved longitudinally relative to the barrel  104  the flushing fluid (e.g., air, an inert gas, a fluid immiscible with the reagent mixture  400  and the like) within the flushing fluid chamber  600  is pushed out of the flushing fluid chamber  600  and through the flushing path  602  into the reaction chamber  208 . Delivery of the flushing fluid into the reaction chamber  208  pushes the reagent mixture  400  out of the dispensing tip  206 . 
     In one example, the flushing fluid chamber  600  includes a volume in the orientation shown in  FIGS. 6A and 6B  greater than the volume of the reaction chamber  208 . For instance, the reaction chamber  208  is included in the reagent reservoir  210  shown in  FIG. 2A . Movement of the barrel  104  into the reagent reservoir  210  shrinks the reagent reservoir leaving only the reaction chamber  208  with the reagent  204  and later the reagent mixture  400  therein. Shrinking the volume of the reagent reservoir  210  to that of the reaction chamber  208  ensures the greater volume of flushing fluid from the flushing fluid chamber  600  fully dispenses the reagent mixture  400  from the dispensing tip  206 . Stated another way, because the flushing fluid within the flushing fluid chamber  600  includes a greater volume than the reaction chamber  208  movement of the activator  106  and the second plunger  202  provides a steady stream of flushing fluid to the small volume of the reaction chamber  208  that reliably pushes the reagent mixture  400  from the dispensing tip  206  and continues to flush any residue of the reagent mixture  400  from the reaction chamber  208  until the second plunger  202  is fully translated through the flushing fluid chamber  600 . 
     Referring now to  FIG. 7 , once the activator  106  is fully moved relative to the barrel  104  the first activator flange  704  is engaged with the second barrel stop  702 . Additionally, in another example, the second plunger  202  including the second plunger gasket  222 , is engaged with the first barrel stop  700  formed in the barrel  104 . Engagement of the flange  704  and the second plunger  202  with the corresponding stops provides an affirmative notification to the technician that the flushing fluid from the flushing chamber  600  is fully pushed through the reaction chamber  208  and the reagent mixture  400  is thereby fully dispensed from the device  100 . That is to say, full translation of the activator  106  relative to the barrel  104  is configured to dispense the entire amount of reagent mixture  400  from the dispensing tip  206  while providing an affirmative notification to the technician that the reagent mixture  400  is dispensed without residue within the reaction chamber  208 . 
       FIG. 9  shows one example of a method  900  for making a reagent preparation and dispensing device such as the reagent preparation and dispensing device  100  shown in  FIG. 2A . Reference is made in the description of the method  900  to elements, features and the like described previously herein. Where reference is made to a numbered element or other feature the reference is not limiting but instead includes similar elements described herein as well as their equivalents. 
     At  902 , the method  900  includes positioning a solution, such as the solution  212  shown in  FIG. 2A , within a body  102 . As shown in  FIG. 2A , the solution  212 , in one example, is positioned within a solution reservoir  214  within a barrel  104  movably coupled within the body  102 . As further shown in  FIG. 2A , the solution reservoir  214  formed by an interior surface of the barrel  104  and a first plunger  200  positioned within the barrel  104 . As will be described in further detail below, the solution reservoir  214  is further sealed by a reservoir seal  226  interposed between the solution reservoir  212  and the reagent  204 . 
     At  904 , a reagent  204  is positioned within a reaction chamber  208  in the body  102 . The reagent  204  is isolated from the solution  212  in the as delivered configuration (See  FIG. 2A ). In one example, a reservoir seal  226  is positioned between the solution reservoir  214  and the reagent reservoir  210  containing the reagent  204 , as will be described in further detail below. The body  102 , in one example, is intended to include the dispensing tip  206  shown in  FIG. 2A . In another example, the dispensing tip  206  including the reagent reservoir  210  and the reagent  204  are considered separate components from the body  102 . 
     At  906 , an activator  106  is movably coupled with the body  102 . The activator  106  is movable to force the solution  212  into the reaction chamber  208  and form a reagent mixture, such as the reagent mixture  400  shown in  FIG. 4A . In one example, the activator  106  is selectively coupled with a first plunger  200 . Movement of the activator  106  is transmitted to the first plunger  200  to force the solution  212  into the reaction chamber  208 . As was described above, in one example, lugs and stops on one or more of the activator  106  and the first plunger  200  facilitate selective engagement between the activator and the first plunger  200 . During the reconstitution and dispensing process the activator  106  is selectively engaged and disengaged from the first plunger  200  to add the solution to the reaction chamber  208  to form the reagent mixture  400  and later dispense the reagent mixture  400  from the dispensing tip  206 . 
     At  908 , a closed dispensing tip  206  (see  FIG. 2A ) is formed extending from the reaction chamber  208  out of the body  102 . As shown in  FIG. 2A , the dispensing tip  206 , in one example, includes the reaction chamber  208  and the remainder of the dispensing tip  206  extends away from the reaction chamber  208  toward a frangible tip  238 . In another example, the frangible tip  238  shown in  FIGS. 2A and 2B  closes the dispensing tip  206  prior to dispensing of the reagent mixture  400  (see  FIG. 4A ) from the reagent preparation and dispensing device  100 . Optionally, the frangible tip  238  cooperates with the reservoir seal  226  to close the dispensing tip  206  having the reagent reservoir  210  (including the reaction chamber  208  and reagent  204 ) from the environment exterior to the device  100 . Isolating the reagent reservoir  210  and the reagent  204  from the exterior environment substantially prevents the ingress of moisture into the reagent reservoir  210  and thereby prevents undesired premature reconstitution of the reagent  204 . 
     In  910 , a vent path  408  is formed within the reagent preparation and dispensing device  100 . The vent path  408  extends from the reaction chamber  208  to outside of the body  102 . The vent path  408  vents gas from the reaction chamber  208  displaced by the addition of the solution  212  to the reaction chamber. In one example, the vent path  408  vents gas and continues to vent gas from the reaction chamber throughout movement of the activator  106  from a starting position (see  FIGS. 3A, 3B ) to a seated position, such as the seated position shown in  FIGS. 4A and 4B . Stated another way, the vent path  408  remains open throughout the entire range of travel of the first plunger  200 . By maintaining the vent path  408  in an open configuration throughout the range of travel of the first plunger  200  gas is continuously vented from the reaction chamber  208  thereby allowing for the full addition of the solution  212  to the reaction chamber. Pressurization and over pressure within the reaction chamber  208  capable of resisting the movement of the activator  106  and the selectively coupled first plunger  200  are thereby substantially avoided allowing for the full addition of the solution to the reaction chamber  208  without opposition due to the over pressure. 
     Several options for the method  900  follow. In one example, the method  900  includes movably coupling a barrel, such as barrel  104 , with the body  102 . In one example, the barrel  104  is coupled with the body  102  through a mechanical fitting  218  interposed therebetween. For instance, surfaces of the barrel  104  and opposed surfaces of the body  102  include threading sized and shaped to rotatably engage the barrel  104  with the body  102 . Rotation of the barrel  104  relative to the body  102  longitudinally moves the barrel  104  as well as the activator  106  and first plunger  200  positioned within the barrel  104 . The activator  106 , first plunger  200  and the barrel  104  thereby move as a single assembly relative to the body  102  as the barrel  104  is moved longitudinally relative to the body  102 . 
     In another example, forming the vent path  408  includes extending the vent path between the barrel  104  and the body  102 . As shown, for instance in  FIG. 4B , the vent path  408  extends from the reaction chamber  208  through reaction chamber vents  410  formed between the dispensing tip  206  and the barrel  104 . The vent path  408  continues along the barrel  104  and reaches the barrel passages  412 . The barrel passages  412  extend through the barrel  104  and into the interior of the barrel adjacent to the first plunger  200 . The vent path  408  thereafter continues along the first plunger  200  and extends between the first plunger  200  and the barrel inner wall  604  (e.g., a vent wall). The vent path  408  continues on past the second plunger  202  including, in one example, a second plunger gasket  222 . As shown, the vent path  408  continues to extend through the barrel  104  along the barrel inner wall (e.g., vent wall) past activator lugs  308  and out of the barrel  104 . In one example, a first portion of the vent path  408  includes the portion of the vent path extending from the reaction chamber  208  along an exterior of the barrel  104  to the barrel passages  412 . A second portion of the vent path  408  extends through the interior of the barrel  104  between the inner barrel wall  604  and the first plunger  200 . In another option, the second portion of the vent path  408  continues through the interior of the barrel  408  along the barrel inner wall  604  and the second plunger  202  and activator  106 . 
     In another example, forming the vent path  408  includes forming the vent path through the body  102  from a reaction chamber  208 . Further, forming the closed dispensing tip  206  includes forming a closed dispensing tip extending from the reaction chamber  208  in a direction opposed to the direction of the vent path  408 . In still another example, forming the closed dispensing tip  206  includes extending the closed dispensing tip  206  from a first portion of the reaction chamber  208  such as a bottom most portion of the reaction chamber. Forming the vent path  408  includes extending the vent path  408  from a second portion of the reaction chamber (e.g., an upper portion) opposed to the first portion of the reaction chamber  208 . By orienting the vent path  408  relative to the dispensing tip  206  the reagent preparation and dispensing device  100  is maintained in a single orientation such as a vertical orientation throughout the reconstitution and dispensing procedure. Rotation of the device  100 , for instance, rotating the device into an orientation with the dispensing tip  206  oriented up and the activator  106  oriented down to vent gases from the reaction chamber is thereby avoided. 
     The vent path  408  facilitates the continued addition of solution to the reaction chamber  208  despite the closed dispensing tip  206 . That is to say, while the dispensing tip  206  is closed (e.g., with the frangible tip) the vent path  408  vents gases displaced from the reaction chamber  208  by the addition of solution  212 . The solution  212  is added to the reaction chamber  208  without developing an over pressure within the reaction chamber capable of opening the dispensing tip and dispensing the reagent mixture  408  prior to full reconstitution. Further, the first plunger  200  encounters no resistance from pressurization while pushing the solution  212  because the gas within the reaction chamber is vented. 
     In yet another example, the method  900  further includes forming a flushing chamber  600  within the body  102 . For instance, as shown in  FIG. 6A  the flushing chamber  600  is formed within the body  102  between the barrel  104  and the first plunger  200 . The flushing chamber  600  includes a flushing fluid in fluid communication with the reaction chamber  208  through the vent path  408  (e.g., the flushing path  602 ). In one example, the vent path  408 , at least in part, becomes the flushing path  602  after closing of the vent path  408  through engagement of the second plunger  208  with the interior of the barrel  104 . In another example, the method  900  includes movably coupling a second plunger  202  with the body  104  (e.g., the barrel  104 ) and the second plunger is operable to close the vent path  408  and push the flushing fluid from the flushing chamber  600  through the vent path  408  (e.g., the flushing path  602 ) into the reaction chamber  208 . Stated another way, movement of the second plunger  202  relative to the body  102  and the barrel  104  seals the vent path  408 . Continued movement of the second plunger  202  pushes flushing fluid from the flushing chamber  600  along a flushing path  602  formed by a portion of the vent path  408  into the reaction chamber  208 . The reagent preparation and dispensing device  100  thereby uses the features and elements defining the vent path  408  for dispensing of the reagent mixture  400  from the dispensing tip  206 . 
       FIG. 10  shows another example of a method  1000  for using a reagent preparation and dispensing device, such as the device  100  shown in  FIGS. 1 through 8F . Reference is made to elements and features described herein using the corresponding numbers previously described. Reference to any particular feature or element is not limiting and instead includes any similar elements described herein as well as their equivalents. 
     At  1002 , a sealed reaction chamber such as the reaction chamber  208  is opened within a body  102  including, for instance, a dispensing tip  206 . The reaction chamber  208  includes a reagent  204 , such as a lyophilized reagent capable of reconstitution through the addition of a solution. In one example, opening the sealed reaction chamber  208  includes moving a barrel  104  relative to the body  102 . The barrel  104 , in one example, includes a piercing surface  236 . Movement of the barrel forces the piercing surface  236  through a reservoir seal  226  and facilitates communication from the reaction chamber  208  to a solution reservoir  214  containing a solution  212 . In another example, the barrel  104  is rotated relative to the body  102  to move the barrel  104  through the reservoir seal  226  to open the reaction chamber  208 . 
     At  1004 , the reagent  204  is reconstituted with a solution  212  retained within the body (e.g., the barrel  104  contained within the body) to form a reagent mixture  400 . In one example, reconstituting the reagent  204  includes adding the solution  212  to the reaction chamber  208 . In one example, the solution  212  is added to the reaction chamber  208  through longitudinal movement of the activator  106  selectively engaged with the first plunger  200  (see  FIGS. 3A, 4A ). Longitudinal movement of the activator  106  correspondingly moves the first plunger  200  and forces the solution  212  out of the barrel  104  and into the reaction chamber  208  to form the reagent mixture  400 . In one example, movement of the barrel  104  relative to the body  102  fills the reagent reservoir  212  leaving the reaction chamber  208  (optionally a portion of the reagent reservoir  210 ). The addition of the solution  212  is thereby limited to the reaction chamber  208  to localize the solution  212  to the area of the reagent reservoir  210  having the reagent  204 . 
     At  1006 , gases in the reaction chamber  208  are vented from the reaction chamber, for instance, along a vent path  408  formed within the reagent preparation and dispensing device  100 . The reaction chamber gas is displaced by the addition of the solution  212  to the reaction chamber  208 . The vented gas passes through the vent path  408  extending through the body  102  away from the dispensing tip  206 . In one example, the body  102  includes the barrel  104 . As previously described above and shown in  FIGS. 4A and 4B , the vent path  408  in another example extends from the reaction chamber  208  through the reaction chamber vents  410  formed in the dispensing tip  206 . A first portion of the vent path  408  extends along an exterior of the barrel  104  toward barrel passages  412  extending through the barrel  104 . A second portion of the vent path  408  continues through the barrel  104  along a barrel inner wall (e.g., a vent wall) and the first plunger  200 . The second portion of the vent path  408  continues along the second plunger  202  through the barrel  104 . As shown in  FIG. 4B , in one example, the vent path  408  extends around activator lugs engaged with corresponding barrel stops  406  formed in the barrel  104 . The vent path  408  continues out of the barrel  104  to allow venting of the reaction chamber gases to the exterior of the reagent preparation and dispensing device  100 . Venting of the reaction chamber gases substantially prevents pressurization of the reaction chamber  208  during reconstitution of the reagent  204 . Further, preventing pressurization within the reaction chamber  208  facilitates the addition of the solution  212  to the reaction chamber  208  by substantially eliminating resistance otherwise provided by over pressurization within the reaction chamber  208 . 
     At  1008 , a specified amount of the reagent  400  is dispensed from the reagent preparation and dispensing device  100 . Dispensing, in one example, includes closing the vent path  408  and pushing a flushing fluid, such as air, through the vent path  408  (e.g., the flushing path  602 ) into the reaction chamber  208 . That is to say, once the vent path  408  is closed, such as by engagement of the second plunger  202  with an interior barrel inner wall  604  of the barrel  104 , flushing fluid from a flushing chamber  600  is pushed along a flushing path  602  into the reaction chamber  208 . The flushing path  602  utilizes a part of the second portion of the vent path  408  as well as the first portion of the vent path  4008  extending from the barrel passages  412  to the reaction chamber vents  410 . That is to say, the method  1000  includes forcing a flushing fluid from the flushing chamber  600  into the reaction chamber  208  to dispense the specified amount of the reagent mixture  400  from the device  100  (see  FIG. 7 ). 
     In one example, venting gas includes venting gas through the body  102  in a direction opposed to the direction of dispensing the specified amount of the reagent mixture  400 . For instance, venting of the reaction gas through the vent path  408  is conducted vertically through the device  100  in a first direction toward the activator  106 . The dispensing of the reagent mixture  400  is performed in second opposed direction away from the body  102 . By venting the reaction chamber gases in an opposed direction the reagent preparation and dispensing device  100  is maintained in a single vertical orientation as shown through  FIG. 8A through 8F  during the reconstitution and dispensing steps. 
     In another example, reconstituting of the reagent  204  is conducted adjacent to the dispensing tip  206  in a first portion of the reaction chamber  208 . The reaction chamber gases are vented from a second portion of the reaction chamber remote from the first portion of the reaction chamber. That is to say, the reconstitution of the reagent  208  is conducted at a bottom portion of the reaction chamber  208  and the venting of the displaced reaction chamber gases begins at a second portion of the reaction chamber opposed to the bottom portion of the reaction chamber. 
     In another example, dispensing the specified amount of the reagent mixture  400  includes moving a plunger such as the second plunger  202  relative to the body  102 . Movement of the second plunger  202  closes the vent path  408  by engaging the plunger  202  with a vent wall (e.g., the barrel inner wall  604 ) to seal a flushing chamber  600  formed by the plunger  202  and the vent wall. Pushing of the flushing fluid from the flushing chamber  600  through the vent path includes moving the plunger  202  through the flushing chamber  600 . 
     In still another example, the method  1000  includes removing a frangible portion of the dispensing tip such as a frangible tip  238 . Removal of the frangible tip opens the dispensing tip  206  and provides an open orifice for dispensing of the reagent mixture  400  according to movement of the actuator  106  and the second plunger  202 . 
     CONCLUSION 
     The reagent preparation and dispensing device shown herein including the methods for making and using the same provide a consolidated device capable of separately retaining a reagent and a solution where the reagent is configured for reconstitution through addition of the solution. The reagent preparation and dispensing device isolates the reagent to substantially prevent the ingress of moisture and thereby preserves the reagent until reconstitution is desired and performed through operation of the device. When operated the reagent preparation and dispensing device is actuated through movement of activator and one or more plungers. The activator and plungers are selectively engaged to prevent movement of the activator relative to one or more of the plungers, the device body and a barrel moveably coupled with the body. By selectively engaging the activator with one or more of the plungers, the body and the barrel staged operation of the reagent preparation and dispensing device is performed. That is to say, each step of the reconstitution and dispensing process is performed by one or more movements of the activator, the barrel, the plunger and the like. As each step of the reconstitution and dispensing process is performed the technician receives affirmative physical feedback from the device indicating completion of the immediate step and readiness of the reagent preparation and dispensing device for the next step of reconstitution and dispensing. By providing staged operation of the reagent preparation and dispensing device the technician is ensured the reagent is fully reconstituted and the specified amount of the reagent is fully dispensed from the device. 
     As shown herein, the reagent preparation and dispensing device includes one or more vent paths extending from the reaction chamber containing the reagent and containing the reagent mixture after addition of the solution to the reagent. The vent path vents gases from the reaction chamber displaced by the addition of the solution and substantially prevents the development of overpressure within the reaction chamber during reconstitution. By minimizing the development of the pressure within the reaction chamber the technician is able to easily reconstitute the reagent through the addition of the solution without resistance to movement of the activator through back pressure developed within the reaction chamber. Further, by venting reaction chamber gases from the reaction chamber over pressure developed within the reaction chamber is thereby avoided to substantially prevent the risk of premature opening of a dispensing tip or the braking of a seal of the reaction chamber. The reagent is thereby fully reconstituted prior to dispensing of the reagent from the device. 
     In another example, the vent path allows the reagent preparation and dispensing device to remain in a single upright orientation throughout the reconstitution and dispensing process. Because the vent path extends away from the dispensing tip the reaction chamber gases are vented in a direction opposed to the direction of dispensing thereby allowing the dispensing tip to remain closed throughout the reconstitution process. That is to say, because the dispensing tip and the reaction chamber are sealed (except for the vent path) reconstitution of the reagent is performed in the same orientation used to both breach the seal between the reagent and the solution reservoirs and dispense the reagent mixture. The technician is thereby able to easily reconstitute and dispense the reagent mixture from the device without considering changing the orientation of the device to ensure pressures are not developed within the reaction chamber and the dispensing tip. 
     Further, in other examples, the reagent preparation and dispensing device includes a flushing chamber sized and shaped to ensure full dispensing of the reagent mixture from the device. As previously described, the flushing chamber, in one example, uses a chamber with flushing fluid having a larger volume relative to the smaller volume of the reaction chamber. Movement of the large volume of flushing fluid through the smaller reaction chamber ensures the specified amount of the reagent mixture is fully flushed from the reaction chamber through the dispensing tip of the device. Residual reagent mixture is thereby cleaned from the reaction chamber and fully dispensed from the reagent preparation and dispensing device. In the example where the reagent preparation and dispensing device includes the flushing chamber the use of a plunger physically engaged with the reagent mixture to dispense the mixture from the device is not needed. Stated another way, because the flushing chamber of the device described in an example herein has a larger volume than the reaction chamber the device is not limited to the displacement caused by a plunger physically engaged with the reagent mixture (e.g., in other words a 1:1 ratio of displacement by the plunger relative to a corresponding volume of a reagent mixture dispensed from the reservoir). 
     In another example, the reagent preparation and dispensing device with the flushing chamber uses a portion of the vent path as a flushing path to transmit the flushing fluid from the flushing chamber into the reaction chamber for dispensing of the reagent mixture. That is to say, the vent path is a two-way passage allowing the venting of the reaction chamber gases from the reaction chamber in an opening configuration. And in a closed configuration, the vent path allows the transmission of flushing fluid in an opposite direction into the reaction chamber to force the reagent mixture from the reaction chamber out of the device. In still another example, the reagent preparation and dispensing device as described herein use a plunger physically engaged with reagent mixture to dispense the reagent mixture from the device without needing a flushing fluid chamber. 
     Although the present disclosure has been described in reference to preferred embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the present disclosure. It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. It should be noted that embodiments discussed in different portions of the description or referred to in different drawings can be combined to form additional embodiments of the present application. The scope of the present disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.