Fingertip conforming fluid expression cap
A bodily fluid sampling device includes an incision forming device to form an incision in a finger and an expression cap. The expression cap has an opening through which the incision forming device forms an incision and an expression surface to express fluid from the incision. The expression surface has at least two opposing compression surfaces with a negative sigmoidal shape to enhance expression of body fluid from the incision. The expression cap defines a relief notch between the compression surfaces, and the relief notch is sized to receive the finger, or some other body part, to permit the compression surfaces to first contact the finger when the expression surface is pressed against the finger.
The present invention generally relates to bodily fluid sampling devices and more specifically, but not exclusively, to a bodily fluid sampling device with an expression cap that allows a more complete contact with the skin around an incision.
A variety of devices have been developed to sample bodily fluids. These devices may use a needle to prick a finger or other means of forming an incision in the body. The devices are commonly used on the finger because the finger contains a high density of capillaries full of blood. Other devices are used to take bodily fluid samples from alternate site testing (AST) locations such as the forearm. These AST locations commonly make it less painful for the user; however, the amount of bodily fluid bled from an incision is commonly lower. Typically, the devices are hand held and are placed against the finger or some other body part. An incision is formed and bodily fluid from the incision is drawn onto a test strip or some other testing device. For example, the test strip can be used to determine the levels of selected analytes in the bodily fluid, such the blood glucose levels.
Sometimes the amount of blood naturally bled from the incision is insufficient for testing purposes, and additional fluid needs to be expressed from the incision before the fluid can be analyzed. Bodily fluid can be expressed from incisions in a number of manners, such as with a vacuum and/or mechanically. In one form, a sampling device with a hollow, cylindrically shaped expression member is pressed around an incision in a finger or some other body part. By pressing the expression member around the incision, the pressure of the bodily fluid in the skin inside the expression member increases so that additional fluid is forced out of the incision. One problem associated with this expression member design is that the contact surface of the expression member is flat, whereas most body parts are not. This flat type of expression member design in turn leads to uneven pressure being applied around the incision, which can block blood flow to the incision, while at the same time allow blood to flow away from the incision site. For example, when a flat expression member is pressed against a finger, uneven pressure is applied around the incision site. Specifically, the expression member blocks the flow of blood in the arteries along the finger, while at the same time allows blood to escape from the sides of the finger. This uneven contact between the expression member and the skin can lead to the user having to attempt to express the fluid over again, and may even require the user to lance the skin again.
Thus, the need remains for further contributions in this area of technology.
SUMMARYIn one aspect of the present invention, a bodily fluid sampling device includes an incision forming device to form an incision in a finger and an expression cap. The expression cap has an opening through which the incision forming device forms an incision and an expression surface to express fluid from the incision. The expression surface has at least two opposing compression surfaces with a negative sigmoidal shape to enhance expression of body fluid from the incision. The expression cap defines a relief notch between the compression surfaces, and the relief notch is sized to receive the finger, or some other body part, to permit the compression surfaces to first contact the finger when the expression surface is pressed against the finger.
Another aspect concerns, a bodily fluid sampling device that includes means for forming an incision in a body part and an expression cap. The expression cap defines an opening through which the means for forming the incision forms the incision. The expression cap has an expression surface, and the expression surface defines a relief notch. The expression surface is shaped to apply a generally even force against the body part when expressing body fluid from the incision.
A further aspect concerns a technique for expressing body fluid. A sampling device has an expression surface with at least two opposing compression surfaces that have a negative sigmoidal shape and a relief notch defined between the compression surfaces that is shaped to generally conform to a body part. The expression surface is placed against the body part with at least a portion of the body part received in the relief notch. An incision is formed in the body part with the sampling device, and the body fluid is expressed from the incision by exerting pressure between the body part and the expression surface.
BRIEF DESCRIPTION OF THE DRAWINGS
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations, modifications, and further applications of the principles of the present invention as illustrated are contemplated as would normally occur to one skilled in the art to which the invention relates.
A bodily fluid sampling device according to one embodiment includes an expression cap having an expression surface with a relief area to allow an improved contact between the expression surface and the body area from which bodily fluid is to be sampled. The relief area centers the contact area around the incision formed in the body part. The combination of a concave expression surface with the relief area creates a more even compressive force to help express the fluid out of the body part contacting the expression surface.
An expression cap 20 according to one embodiment, among others, is illustrated in
As illustrated, the expression surface 24 has relief notches 26 that improve the contact with the skin surrounding the expression surface 24. In the illustrated embodiment, the relief notches 26 are shaped to generally conform to the shape of a finger, but it should be appreciated that the notches 26 can be shaped to conform to other body parts, such as the forearm. By generally conforming to the shape of the finger, the relief notches 26 permit a generally even pressure to be applied against the skin around the incision, which in turn increases the amount of fluid expressed from an incision. In the illustrated embodiment, the expression surface 24 surrounding the notches 26 has a negative sigmoid shape because it was discovered that the negative sigmoid shape of the expression surface 24 in conjunction with the relief notches 26 was particularly effective in expressing fluid. The negative sigmoid shape of the expression surface 24 promotes fluid flow from the sides of the finger towards the incision. In one embodiment, the relief notches 26 can be configured to not cut off the circulatory flow of blood in the arteries along the finger, thereby permitting an even greater blood flow from the incision.
The support portion 22 includes a depression 27 for gripping the expression cap 20. In this embodiment, the depression 27 is depicted having a parabolic shape, but it is envisioned that the depression can be shaped differently in other embodiments. In one form, the depression 27 is shaped to conform to human fingers for easy grasping of the expression cap 20 during insertion or removal of the expression cap 20 from a sampling device. As illustrated in
Referring now to
With continued reference to
In
With reference to
As depicted in
A bodily fluid sampling device 57, according to one embodiment, that incorporates the expression cap 20 is illustrated in
The cap 20 is detachably secured to the body 59 to permit removal and replacement of the cap 20. To improve hygiene, the expression cap 20 in one embodiment is disposable; that is, the expression cap 20 is discarded and replaced with a new one after every test. It is contemplated that in other embodiments the cap 20 can be non-disposable such that it is removed and cleaned after every test. As shown in
As depicted in
A technique for collecting and analyzing body fluid with the sampling device 57 will now be described with reference to
After the incision is formed, a force F is applied by the cap 20 against the finger 71 to express fluid from the finger 71, as is illustrated in
In the illustrated embodiment, the body fluid 75 on the finger 71 is collected on test media 77 that disposed inside the expression 20. The test media 77 in the illustrated embodiment is in the form of a test strip that is used to analyze the body fluid 75. It is contemplated that the fluid 75 can be collected and analyzed in other manners. For example, the test media 77 can include an integrated lancing test strip in which the lancet 67 and the test strip 77 are configured as a unitary device that is able to lance the skin, sample the fluid and analyze the fluid sample. As should be appreciated, analyte levels can be determined through the chemical, electrical, electrochemical and/or optical properties of the bodily fluid sample collected on the test media, to name a few. For example, the test media 77 as illustrated is a chemically reactive reagent test strip. Typically, reagent test strips are sensitive to thermal and/or chemical processes required for sterilization. The sterilization process can effect the results generated by the test media 77, and therefore, recalibration of the test media 77 is required after sterilization. In the embodiment illustrated in
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.
Claims
1. A bodily fluid sampling device, comprising:
- an incision forming device to form an incision in a finger; and
- an expression cap defining an opening through which the incision forming device forms an incision, the expression cap having an expression surface to express fluid from the incision, the expression surface having at least two opposing compression surfaces with a negative sigmoidal shape to enhance expression of body fluid from the incision, the expression cap defining a relief notch between the compression surfaces, the relief notch being sized to receive the finger to permit the compression surfaces to first contact the finger when the expression surface is pressed against the finger.
2. The sampling device of claim 1, wherein:
- the expression cap includes a support portion and an expression portion detachably coupled to the support portion, wherein the expression portion is detachable from the support portion to allow cleaning of the expression portion.
3. The sampling device of claim 1, further comprising a testing device disposed in the expression cap for analyzing the fluid from the incision.
4. The sampling device of claim 1, wherein the expression surface is textured to enhance expression of fluid from the incision.
5. The sampling device of claim 4, wherein the expression surface defines a plurality of ridges.
6. The sampling device of claim 1, wherein the relief notch extends on opposite sides of the opening.
7. The sampling device of claim 1, further comprising a device body coupled to the expression cap.
8. The sampling device of claim 7, wherein the expression cap is removable from the device body.
9. A bodily fluid sampling device, comprising:
- means for forming an incision in a body part; and
- an expression cap defining an opening through which the means for forming the incision forms the incision, the expression cap having an expression surface, the expression surface defining a relief notch, wherein the expression surface is shaped to apply a generally even force against the body part when expressing body fluid from the incision.
10. The sampling device of claim 9, wherein the expression surface has a negative sigmoid shape.
11. The sampling device of claim 9, wherein the expression surface has a saddle shape.
12. The sampling device of claim 9, wherein the relief notch extends across the opening.
13. The sampling device of claim 9, wherein the expression cap has a generally cylindrical shape.
14. The sampling device of claim 9, wherein an area of contact between the expression surface and the body part has a surface area between about 0.2 to 0.6 square inches.
15. A method, comprising:
- providing a sampling device that has an expression surface with at least two opposing compression surfaces that have a negative sigmoidal shape and a relief notch defined between the compression surfaces that is shaped to generally conform to a body part;
- placing the expression surface against the body part with at least a portion of the body part received in the relief notch;
- forming an incision in the body part with the sampling device; and
- expressing body fluid from the incision by exerting pressure between the body part and the expression surface.
16. The method of claim 15, wherein the expression surface has a negative sigmoid shape.
17. The method of claim 15, further comprising analyzing the body fluid with the sampling device.
18. The method of claim 15, further comprising keeping the sampling device in place against the body part during said forming and said expressing.
19. The method of claim 15, wherein said placing the expression surface against the body part occurs before said expressing the body fluid.
20. The method of claim 15, wherein said expressing includes pressing the body part against the expression surface.
21. The method of claim 15, wherein said expressing includes pressing the expression surface against the body part.
22. The method of claim 15, wherein:
- the sampling device includes an incision forming device;
- the expression surface defines an opening; and
- said forming the incision includes forming the incision through the opening with the incision forming device.
Type: Application
Filed: Mar 26, 2004
Publication Date: Sep 29, 2005
Inventor: Christopher Wiegel (San Jose, CA)
Application Number: 10/811,268