Surgery – Diagnostic testing – Liquid collection
Reexamination Certificate
2001-06-14
2004-03-16
Marmor, Charles (Department: 3736)
Surgery
Diagnostic testing
Liquid collection
C600S573000, C606S181000
Reexamination Certificate
active
06706000
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a body fluid testing device and methods for obtaining samples of blood fluid for analysis.
BACKGROUND OF THE INVENTION
Many medical procedures in use today require a relatively small sample of body fluid, for example in the range of 0.1-50 micro liters. It is more cost effective and less traumatic to the patient to obtain such a sample by lancing or piercing the skin at a selected location, such as the finger or forearm, to enable the collection body fluid. With the advent of home use tests for the self monitoring of blood glucose, there is a requirement for a simple procedure which can be performed in any setting without a person needing the assistance of a professional.
One device which is commonly utilized to form an opening in the patient's skin is a lancets. Lancets generally have a rigid body and a sterile lance which protrudes from one end. The lancet may be used to pierce the skin, thereby enabling the collection of a body fluid sample from the opening created. The body fluid sample is transferred to a test device or collection device. Body fluid is most commonly taken from the fingertips, where the supply is generally excellent. However, the nerve density in this region causes significant pain in many patient's. Sampling of alternative sites, such as earlobes and limbs is sometimes practiced to lessen the pain. These sites are also less likely to provide excellent body fluid samples and make body fluid transfer directly to test devices difficult. Examples of body fluids which may be utilized to test for glucose are blood and interstitial fluid.
Repeated lancing in limited surface areas, such as fingertips, results in callous formation. This leads to increased difficulty in drawing body fluid and increased pain.
To reduce the anxiety of piercing the skin and the associated pain, many spring loaded devices have been developed wherein the device automatically triggers in response to an applied force. Thus the user cannot anticipate the exact timing of the piercing, thus they are less likely to pull the device away during use. The following two patents are representative of the devices which were developed in the 1980's for use with home diagnostic test products.
U.S. Pat. No. 4,503,856, Cornell et al., describes a spring loaded lancet injector. The reusable device interfaces with a disposable lancet. The lancet holder may be latched in a retracted position. When the user contacts a release, a spring causes the lancet to pierce the skin at high speed and the retract. The speed is important to reduce the pain associated with the puncture.
Levin et al., U.S. Pat. No. 4,517,978 describes a blood sampling instrument. This device, which is also spring loaded, uses a standard disposable lancet. The design enables easy and accurate positioning against a fingertip so the impact site can be readily determined. After the lancet pierces the skin, a bounce back spring retracts the lancet to a safe position within the device.
In home settings it is often desirable to collect a body fluid sample in order to enable a user to perform a test at home, such as glucose monitoring. Some blood glucose monitoring systems, require that the blood sample be applied to a test device wich is in contact with the test instrument. In such situations, bringing the finger to the test device poses some risk of contamination of the sample with a previous sample that may not have been properly cleaned from the device. Glucose monitoring devices may utilize a blood sample in many ways, though the two most common methods for collection are a paper strip and a capillary tube. Monitors that utilize a paper strip, require the patient to pierce a finger or appropriate location, withdraw a small sample of blood from the pierced area, such as by squeezing, and then placing the paper strip in physical contact with the blood sample and waiting until the paper strip absorbs the blood. Monitors that utilize a capillary tube for fluid collection, require the patient to follow the process described above, except that a paper strip is not utilized, instead a small capillary tube is placed over the sample until a sufficient amount of blood is withdrawn into the capillary tube and to the glucose testing area of the testing device.
Many times due to dexterity problems or poor eye site it can be difficult for the patient to either bring the body fluid sample to the testing area or to bring a capillary tube to the fluid sample. Additionally, some patient's have a fear of bodily fluids, such as blood, and would prefer not to see this type of body fluid.
Amira Medical Inc. introduced a new method for home glucose testing. Amira's device AtLast 7, tests blood glucose levels by taking blood from the skin of the forearm, which is a much less sensitive than the fingertips. This device has been very well received by both the diabetic community as well as the blood glucose measurement industry.
Haynes, U.S. Pat. No. 4,920,977 describes a blood collection assembly with a lancet and micro-collection tube. This device incorporates a lancet and collection container in a single device. The lancing and collection are two separate activities, but the device is a convenient single disposable unit for situations when sample collection prior to use is desirable. Similar devices are disclosed in Sarrine. U.S. Pat. No. 4,360,016 and O'Brian, U.S. Pat. No. 4,924,879.
Jordan et al., U.S. Pat. No. 4,850,973 and U.S. Pat. No. 4,858,607 disclose a combination device which may be alternatively used as a syringe-type injection device and a lancing device with disposable solid needle lancet, depending on configuration.
Lange et al., U.S. Pat. No. 5,318,584 describes a blood lancet device for withdrawing blood for diagnostic purposes. This invention uses a rotary/sliding transmission system to reduce the pain of lancing. The puncture depth is easily and precisely adjustable by the user.
Suzuki et al., U.S. Pat. No. 5,368,047, Dombrowski, U.S. Pat. No. 4,654,513 and Ishibashi, et al., U.S. Pat. No. 5,320,607 each describe suction-type blood samplers. These devices develop suction between the lancing site and the end of the device with the lancet holding mechanism withdraws after piercing the skin. A flexible gasket around the end of the device helps seal the end around the puncture site until adequate sample is withdrawn from the puncture sire or the user pulls the device back.
Garcia et al., U.S. Pat. No. 4,637,403 discloses a combination lancing and blood collection device which uses a capillary action passage to conduct body fluid to a separate test strip in the form of a micro porous membrane. It is necessary to achieve a precise positioning of the upper end of the capillary passage with respect o the membrane in order to ensure that the body fluid from the passage is transferred to the membrane. If an appreciable gap exits therebetween, no transfer may occur.
It is difficult for a user to determine whether a sufficiently large drop of body fluid has been developed at the incision for providing a large enough sample.
Single use devices have also been developed for single use tests, i.e. home cholesterol testing, and for institutional use to eliminate the cross-patient contamination multi-patient use. Crosman et al., U.S. Pat. No. 4,869,249, and Swierczek, U.S. Pat. No. 5,402,798, also describe disposable, single use lancing devices.
The disclosures of the above patents are incorporated herein by reference.
An object of the present invention is to provide a one-step procedure and device for testing glucose levels in body fluids.
Another object of the present invention is to provide an apparatus that withdraws a body fluid sample and provides an individual with a body fluid glucose level reading.
Even with the many improvements which have been made, the pain associated with lancing remains a significant issue for many patients. The need for blood sampling and the fear of the associated pain is also a major obstacle for the millions of diagnosed diabetics, who do not adequatel
Perez Edward P.
Raney Charles C.
Roe Jeffrey N.
Amira Medical
Marmor Charles
Woodard Emhardt Moriarty McNett & Henry LLP
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