Cap for a lancing device

#The present invention generally relates to lancing devices for lancing dermal tissue and for withdrawing a fluid sample.

#Lancets in conventional use generally have a rigid body and a sterile needle which protrudes from one end. The lancet may be used to pierce the skin, thereby enabling the collection of a blood sample from the opening. The blood is then transferred to a test collection device. Blood is most commonly taken from the fingertips, where there is generally an abundant supply. However, the nerve density in this region causes significant pain in many patients. Sampling of alternate sites, such as earlobes and limbs, is sometimes practiced to access sites which are less sensitive. These sites are also less likely to provide sufficient blood volume, and make blood transfer directly to test devices difficult.

#Repeated lancing in limited surface areas (such as fingertips) results in callous formation. This leads to increased difficulty in drawing blood and increased pain to the user. To reduce the anxiety of piercing the skin and the associated pain, many spring loaded devices have been developed.

#These and other features and advantages of the present invention will be more fully understood by reference to the following detailed description in conjunction with the attached drawings in which like reference numerals refer to like elements through the different views. The drawings illustrate principles of the invention and, although not to scale, show relative dimensions.

#FIG. 1 is a side elevational view of a cap for a lancing device, illustrating the cap attached to a lancing device in accordance with the teachings of the present invention;

#FIG. 2 is a side elevational view of the cap of FIG. 1;

#The present invention is directed to a cap for use with a lancing device for lancing dermal tissue to express a fluid sample, such as blood, interstitial fluid, or both. We refer below to the expression of blood for purposes of simplicity, although it is intended to encompass the expression of interstitial fluid or both. The cap of the present invention is designed to facilitate the expression of blood after the dermal tissue is lanced by increasing the pressure on the dermal tissue surrounding the lancing site. This increase in pressure results in increased blood flow from the lancing site, thereby reducing the time necessary to express a sufficient quantity of blood and eliminating the need for placing the lancing device on a surface and using the other free hand to squeeze out the sample fluid.

#Moreover, the cap of the present invention is particularly suited for collecting blood samples from lancing sites other than on the fingertip of the patient, which is the traditional location for collecting blood samples. Use of such alternative sites can be less painful to the patient and also allows the patient to “rest” his or her fingertip. Suitable alternative sites include, but are not limited to, the forearms, the upper arms, the thighs, the palms, and the abdomen of a patient. Blood sample collection at alternative sites can be problematic as manually applying sufficient pressure on the dermal tissue proximate the lancing site to collect the blood sample can be difficult and typically results in low yields. The cap of the present invention allows the user to increase the amount of pressure at the lancing site such that a sufficient quantity of blood can be expressed from the alternative sample site.

#A cap 10 in accordance with one preferred embodiment of the present invention is illustrated in FIGS. 1 through 4. The cap 10 is design to be connected to the distal end of the housing 12 of a conventional lancing device. In a conventional lancing device a lancet 30 is mounted within the housing 12 of the lancing device and is movable along a first axis, indicated by line A in FIG. 1, relative to the housing 12. The lancet 30 can be driven along the first axis by the lancing device to puncture the dermal tissue. The blood sample can then be expressed for collection from the lancing site. Such conventional lancing devices are available from Lifescan, Inc. of Milpitas, Calif., Palco Laboratories of Santa Cruz, Calif., Therasense of Alameda, Calif., and Amira Medical of Scotts Valley Calif. In addition, lancing devices are described in U.S. Pat. No. 5,730,753 to Morita, U.S. Pat. No. 6,045,567 to Taylor, and U.S. Pat. No. 6,071,250 to Douglas. Each of the aforementioned patents is incorporated herein by reference. One skilled in the art will appreciate that the cap of the present invention is not limited to the lancing devices described herein. The cap of the present invention can be used with any lancing device employing a movable lancet for lancing dermal tissue. Moreover, the present invention is intended to include any device suitable for expressing a fluid sample from a user employing different extraction techniques, including the use of lancets, hollow and solid needles or microneedles, ultrasonic devices, thermal techniques, and the like. The device can be a simple lancing device as described above, or can include devices having integrated meters or measuring devices suitable for testing an analyte, such as glucose.