Surgery – Diagnostic testing – Liquid collection
Reexamination Certificate
2000-05-26
2003-01-14
Shaver, Kevin (Department: 3736)
Surgery
Diagnostic testing
Liquid collection
C606S181000
Reexamination Certificate
active
06506168
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and apparatus for obtaining samples of blood for diagnostic purposes.
2. Discussion of the Art
The prevalence of diabetes has been increasing markedly in the world. At this time, diagnosed diabetics represent about 3% of the population of the United States. It is believed that the total actual number of diabetics in the United States is over 16,000,000. Diabetes can lead to numerous complications, such as, for example, retinopathy, nephropathy, and neuropathy.
The most important factor for reducing diabetes-associated complication s is the maintenance of an appropriate level of glucose in the blood stream. The maintenance of the appropriate level of glucose in the blood stream may prevent and even reverse many of the effects of diabetes.
Glucose monitoring devices of the prior art have operated on the principle of taking blood from an individual by a variety of methods, such as by needle or lancet. An individual then coats a paper strip carrying chemistry with the blood, and finally inserts the blood-coated strip into a blood glucose meter for measurement of glucose concentration by determination of change in reflectance.
The medical apparatus of the prior art for monitoring the level of glucose in the blood stream required that an individual have separately available a needle or lancet for collecting blood from the individual, strips carrying blood chemistry for creating a chemical reaction with respect to the glucose in the blood stream and changing color, and a blood glucose meter for reading the change in color indicating the level of glucose in the blood stream. The level of blood glucose, when measured by a glucose meter, is read from a strip carrying the blood chemistry through the well-known process of reading reflectometers for glucose oxidation.
Generally lancets comprise a blade and a pressable end opposed thereto, with the blade having an acute end capable of being thrust into skin of a human. By striking the pressable portion, the acute end of the blade will pierce the skin, for example, of the finger. The finger lancet is primarily used to obtain small volumes of blood, i.e., less than 1 mL. Diabetics use the finger lancet to obtain volumes of blood less than 25 &mgr;L for analysis for glucose. A small amount of blood for the blood test will ooze out of the skin. There are many small blood vessels in each finger so that a finger can be squeezed to cause a larger drop of blood to ooze. The finger is one of the most sensitive parts of the body; accordingly, the finger lancet leads to even more pain than what would be experienced by collecting blood via lancet at a different body site. The finger lancet presents another problem because of the limited area available on the fingers for lancing. Because it is recommended that diabetics monitor their blood glucose levels four to six times per day, the limited area on the fingers calls for repeated lancing of areas that are already sore. Because fingers are sensitive to pain, it is a recent tendency that the arm is subjected to blood sampling. See, for example, U.S. Pat. No. 4,653,513. The device of U.S. Pat. No. 4,653,513 comprises a cylindrical housing and a lancet support, which has a gasket or flexible portion slidably accommodated in the housing. Springs will retract the lancet support to thereby reduce air pressure in the housing so that it sucks a blood sample, automatically and immediately after a lancet pierces the skin. See also U.S. Pat. No. 5,320,607, which discloses a device comprising a sealed vacuum chamber in a state of preexisting reduced pressure, a support member for the sealed vacuum chamber, the support member defining a suction portion adjacent the sealed vacuum chamber, the suction portion, in cooperation with the sealed vacuum chamber, exposing an area of the skin of a patient to a reduced pressure state when the device is actuated, and means arranged within the suction portion for slightly rupturing a portion of the area of skin of the patient exposed to the reduced pressure state.
Because the blood volume requirements for a standard glucose test strip are typically 3 &mgr;L or more, an area of the body that can generate that much blood from a lancet wound must be used. It is believed, however, that improvements in glucose test strip technology will reduce the volume of blood needed to 1 to 3 &mgr;L. Because the finger is well supplied with blood and the amount of blood can be increased by squeezing the finger after lancing, the finger is the currently preferred body site for lancing, even though lancing of the finger is painful.
A less painful technique for obtaining body fluids is described in U.S. Ser. No. 08/982,721, filed Dec. 2, 1997. This application discloses an apparatus for obtaining blood for diagnostic tests. The apparatus comprises a housing having a sealable chamber located therein and a sealable opening in fluid communication with the sealable chamber, a power source, a vacuum pump operably connected to the power source, the vacuum pump in communication with the sealable chamber, a lancing assembly positioned within the sealable chamber, and a fluid collector positioned in the sealable chamber, the fluid collector in fluid communication with the sealable opening. It would be desirable to improve that apparatus in order to ensure that the fluid collector is properly positioned in the apparatus during the lancing and fluid collecting steps.
SUMMARY OF THE INVENTION
This invention provides a method and apparatus for collecting a sample of blood from a patient for subsequent diagnostic tests, e.g., glucose monitoring.
In one aspect of the invention, an apparatus for collecting a sample of body fluid, e. g., blood, for analysis in a diagnostic test is provided. In a preferred embodiment, the apparatus comprises:
(a) a housing having a sealable chamber located therein and a sealable opening in fluid communication with the sealable chamber;
(b) a vacuum pump in communication with the sealable chamber;
(c) a device for forming an unobstructed opening in an area of skin from which a sample is to be collected, preferably a lancing assembly, the device positioned within the sealable chamber;
(d) a movable support for supporting and positioning a port for a fluid collector in the sealable chamber, the movable support capable of moving the port within the sealable chamber between a first position and a second position; and
(e) a stop for aligning the fluid collector.
In more preferred embodiments, the apparatus further comprises a power source, and the vacuum pump is operably connected to the power source. The stop aligns the fluid collector so that the fluid collector is capable of being properly positioned in the apparatus during the lancing and fluid collecting steps.
The fluid collector is preferably a test strip that contains at least one chemical reagent for conducting a diagnostic test, e.g., a test for determining blood glucose level. Typically the test strip has an opening formed therein, which opening is capable of being aligned with the sealable opening of the housing. A preferred device for forming an unobstructed opening in the area of the skin from which the sample of blood is to be collected is a lancing assembly, which comprises a lancet for forming an opening in the skin. Alternatively, the unobstructed opening in the skin can be formed by a laser or by a fluid jet. In the case of a lancing assembly, when the lancing assembly is triggered, the lancet of the lancing assembly passes through the opening of the test strip and the sealable opening of the housing to form an opening in the skin of the patient. The sample of body fluid, e.g., blood, is obtained from the opening formed in the skin of the patient. The opening of the test strip should be properly aligned with the sealable opening of the housing before the lancing assembly is triggered, because misalignment of these openings may result in one or more of the following undesirable occurrences: (1) an unsuccessful assay; (2) a longer per
Chambers Geoffrey R.
Fathallah Marwan A.
Abbott Laboratories
Shaver Kevin
Weinstein David L.
Wingood Pamela L.
LandOfFree
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