The quantitative determination of analytes in body fluids is of great importance in the diagnoses and maintenance of certain physiological abnormalities. For example, lactate, cholesterol and bilirubin should be monitored in certain individuals. In particular, determining glucose in body fluids is important to diabetic individuals who must frequently check the glucose level in their body fluids to regulate the glucose intake in their diets. While the remainder of the disclosure herein will be directed towards determining glucose, it is to be understood that the methods of this invention may be used for determining other analytes on selection of an appropriate enzyme.
The results of such tests can be used to determine what, if any, insulin or other medication needs to be administered. In one type of blood glucose testing system, sensors are used to test a fluid such as a sample of blood.
A sensor contains biosensing or reagent material that will react with blood glucose. The testing end of the sensor is adapted to be placed into the fluid being tested, for example, blood that has accumulated on a person's finger after the finger has been pricked. The fluid is drawn into a capillary channel that extends in the sensor from the testing end to the reagent material by capillary action so that a sufficient amount of fluid to be tested is drawn into the sensor. The fluid then chemically reacts with the reagent material in the sensor resulting in an electrical signal indicative of the glucose level in the fluid being tested is supplied to contact areas located near the rear or contact end of the sensor.
Such a sensor is often sensitive to the effects of ambient humidity. One way to reduce or eliminate the effects of ambient humidity is to individually package each of the sensors with desiccant. Such a method has a drawback of requiring the unpacking of a strip before each use. Thus, it would be desirable to have a cartridge that would contain a plurality of test sensors that would not require unpacking each strip before using. Also, for the convenience and case of use, it would also be desirable to have a simple mechanism to feed the test sensors one at a time for testing by the user. This provides ease of use to normal users and is especially important for those users who may have some physical limitations.