Patent Publication Number: US-2003236543-A1

Title: Polygonal cross section lancet needle

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates generally to a lancet needle for lancing fingers and other body sites to obtain small samples of blood or interstitial fluid for diagnostic testing. More particularly, the invention relates to a lancet needle having a polygonal or multisided cross section.  
       BACKGROUND OF THE INVENTION  
       [0002] People with certain medical conditions, such as diabetics, often have to perform diagnostic tests on their blood for glucose and other analytes several times a day. To performn these tests, a site on the body is selected and lanced using a lancet assembly that includes a lancet needle. These lancet needles are made from round stainless steel wires with tips that are ground to form two or three facets on the tips. Round needles force the skin open after initial penetration and only cut at the ground facets which results in a large puncture that is painful and requires a long time to heal.  
       [0003] Recently, instruments for performing diagnostic tests have been developed that require much smaller samples of blood or interstitial fluid than the sample size required by earlier instruments. In addition, patients have demanded less painful lancing methods. Thus, there is a need for lancing needles whose puncture is less painful than current needles and produce a small wound that is quick to heal.  
       SUMMARY OF THE INVENTION  
       [0004] The present invention is directed to a multisided lancet needle that makes a small, quick healing cut at a puncture site. The lancet needle is defined by a body having a polygonal cross section and a first end and a second end. The first end is ground at an angle, for example, an angle between about 5° and about 10°, to form a sharp edge for lancing the skin of a user. The cross section of the needle body can be square, triangular, rectangular, or any similar multisided configuration. 
     
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
     [0005] Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:  
     [0006]FIG. 1 is a perspective view of a square lancet needle with a single cut;  
     [0007]FIG. 2 is a perspective view of a square lancet needle with a double cut;  
     [0008]FIG. 3 is a perspective view of a square lancet needle with a diagonal cut;  
     [0009]FIG. 4 is a perspective view of a triangular lancet needle with a single cut;  
     [0010]FIG. 5 is a perspective view of a rectangular lancet needle with a single cut;  
     [0011]FIG. 6 is a plan view of a round wire with one end ground to a preferred configuration;  
     [0012]FIG. 7 is a view of the wire illustrated in FIG. 6 with the one end ground to define a sharp edge; and  
     [0013]FIG. 8 is an enlarged view of a square lancet needle with a tip ground at an angle. 
    
    
     [0014] While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.  
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS  
     [0015] Referring to FIG. 1, there is illustrated a lancet needle  10  having a square cross section. The lancet needle  10  is formed of stainless steel but other material may be used. The lancet needle  10  has a first end  12  and a second end  14 . The first end  12  has a sharp edge or tip  16  formed by grinding one side  18  of the lancet needle  10  on an angle ∀ to the one side  18 . Preferably, the angle ∀ is in the range of between about 5° to about 10° but other angles may be used. It has been learned that this angle ∀ in the range of about 5° to about 10° provides a sufficiently sharp edge or tip  16  to penetrate and cut human skin and tissue in a very clean way with less pain to the user than the pain experienced using prior art round needles.  
     [0016] Another lancet needle  20  of square cross sectional configuration is shown in FIG. 2. This lancet needle  20  is substantially the same as the lancet needle  10  of FIG. 1 except that its first end  22  is ground on opposite sides  24 ,  26  to form a sharp edge or tip  28 . Each side  24 ,  26  is ground at an angle  3  which preferably is in the range of about 5° to about 10° although other angles may be used.  
     [0017] A third lancet needle  30  of square cross sectional configuration is illustrated in FIG. 3. The lancet needle  30  is ground on a diagonal by a diagonal cut to form a sharp edge or tip  32  on a first end  34  of the lancet needle  30 . The first end  34  is ground diagonally 45° from a first side  36  at an angle in the range of about 5° to about 10° although other angles may be used.  
     [0018] A lancet needle  40  with a triangular cross sectional configuration is shown in FIG. 4. A first end  42  of the lancet needle  40  is ground on a side  44  at an angle X in the range of between about 5° and about 10° to form a sharp chisel point or edge  46 .  
     [0019] In FIG. 5 there is illustrated a lancet needle  50  having a rectangular cross sectional configuration. A first end  52  of the lancet needle  50  has one side  54  ground at angle Y that is in the range of between about 5° to about 10° to define a sharp edge  56  for piercing skin and tissue.  
     [0020] The sharp edges or tips  16 ,  28 ,  32 ,  46 ,  56  of the needles  10 ,  20 ,  30 ,  40 ,  50  penetrate a user&#39;s skin and continue to cut the skin and tissue in a clean way resulting in a lower pain level and a cut or puncture that heals faster than a cut from a conventional round lancet needle. This is because the multisided cross sections cut on all sides and do not force skin open as much as round needles. Thus, multisided configurations such as hexagonal are also contemplated.  
     [0021] Manufacturing these lancet needles  10 ,  20 ,  30 ,  40 ,  50  is similar to the manufacture of conventional round needles. Multisided cross sectional wires are extruded from a round stainless steel wire and cut into short workable lengths for grinding. The tips or first ends of a large number of these wires are ground to the desired angle at the same time. The needles are then cleaned and deburred before being molded in plastic to form a lancet. The molded lancets are then sterilized by radiation.  
     [0022] An alternative method of manufacture can be envisioned which will require less change to the manufacturing of conventional round needles. Rather than extruding round wire to a different cross-section, a conventional round wire  60  is ground on a first end  62  to a preferred multisided cross section (e.g., square, triangular, rectangular, etc.) (FIG. 6). The first end  62  is then ground at an angle from about 5° to about 10° to form a sharp edge or tip  64  (FIG. 7). At this point the ground wire  60  can be insert molded into plastic. This method allows the use of large diameter round wires  60 , 22-26 gauge for example, since the first end  62  can be ground to a small cross section profile (29-32 gauge for example). The larger gauge is easier to handle for manufacturing and has more surface area to lock into molded plastic. This results in the same cutting edges as in the previously described lancets. In addition the step formed at the transition from the round to the smaller cross section will also provide a means of locking the needle into the plastic.  
     [0023] It has been found that grinding an end of a needle at an angle to the longitudinal axis of the needle results in an angle at the tip which can start a cut in skin at an end of the tip rather than a cut being started along the entire length of the tip. This causes less pain to the user or patient. This angled grind is shown in FIG. 8. A lancet needle  110  may be square or rectangular with a first end  112  and a second end  114 . The needle  110  can be ground on one side  118  or a double grind as in FIG. 2 but the grind in FIG. 8 is at an angle to the longitudinal axis of the needle  110  resulting in an angled tip  116  at an angle Y in the range of 0° to 15°.  
     [0024] While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.