The present disclosure relates to an analysis system for determining an analyte in a body fluid having a disposable integrated sample acquisition and analysis element and having a reusable analysis instrument.
For diagnostic, purposes, small quantities of body fluids, such as blood, are taken from a body part. For this purpose, piercing devices having lancets are typically used, such devices generate a wound in the body part, for example, in the finger or in the ear lobe. The piercing systems are implemented in such a manner that they may also be used by laymen.
However, when determining an analyte in the body fluid, a procedure in multiple steps is required. Firstly, a wound must be generated in the body part using a piercing system, which comprises a piercing device and a lancet. A body fluid, such as, for example, blood, then exits from the wound. In a further step, the fluid must be received by a test element and supplied to an analysis system, which determines the desired analyte in the body fluid.
This procedure is complex, in particular for diabetics, who must determine the glucose content in the blood multiple times a day. Therefore, in addition to pain-free piercing as much as possible, increased operating comfort is also required.
In order to come one step closer to the desired operating comfort, integrated analysis systems have been proposed in the prior art, which also comprise an analysis unit in addition to a piercing device. An analysis system is known from WO 2006/027101 A1, in which, after the generation of the wound in the body part, the piercing device is moved away from an opening of the analysis system and an analysis unit is moved to the opening of the system in a second step, so that blood exiting from the wound can be received by the analysis unit.
In order to improve the handling ability and the comfort of the analysis systems, analysis systems have been developed which propose test elements and/or test sensors having an integrated lancet.
For example, an analysis system having a test sensor with an integrated lancet, in which an analyte in a body fluid is determined by an electrochemical measurement is known from WO2006/092281. The disposable test sensor comprises a test strip, on whose top side a capillary channel is provided, which is used to transfer the received body fluid to test electrodes, which are also located on the top side of the test strip, in order to determine an analyte in the body fluid. A lancet is located on the bottom side of the test strip, which is movably mounted relative to the test strip. The lancet is enclosed by a sterile envelope, from which it exits before piercing into the body part.
For the sample acquisition, the test sensor is guided into the vicinity of the opening of the analysis system. The lancet is then moved forward in the puncture direction until it exits from the opening of the receptacle system and generates a wound in a body part which is pressed against the opening. After the puncture, the lancet is retracted again until it is positioned in its sterile protective envelope again. The blood exiting from the puncture wound and/or the exiting body fluid is suctioned in by the capillary channel on the top side of the test strip and finally reaches the electrodes, so that an analyte in the body fluid may be determined electrochemically.
A system of this type has the disadvantage that two separate handling steps are necessary in order to, on the one hand, ensure the puncture in the skin and, on the other hand, ensure the transfer of a sufficiently large blood sample onto the test element.
This may be performed manually, after execution of the puncture, the analysis system being removed from the body part and the body part subsequently being “milked” in order to promote the escape of blood from the wound. As soon as a sufficiently large quantity of blood has exited from the wound, the analysis system is guided back to the wound manually in order to suction the sample into the capillary channel. This requires cumbersome handling by the patient and is difficult in particular for older people, who are frequently affected by diabetes. Alternatively to the manual procedure and the operation comprising multiple steps, the “milking” may be mechanized by the analysis system itself. For this purpose, systems having a so-called finger cone have been proposed. After the piercing procedure, the expression of a liquid sample is caused by pressure on the cone. For this purpose, the manual handling is thus replaced by a corresponding instrument function, which requires significant design effort and makes the instruments more costly, however.
As a third, rather theoretical possibility, which is also opposed by the demand for piercing with as little pain as possible, the lancet may be pierced so deeply into the body part that a sufficiently large blood droplet exits without additional measures such as manual or mechanical milking. The pain connected with the deep piercing is so great, however, that a system of this type is unsuitable for practice.
Therefore, there is a need for an analysis system which is distinguishable from the prior art by a high comfort for the user, in particular in that he only has to hold the analysis system on the body part once in order to determine the desired analyte. In addition, the analysis system will be easy to operate and will be based on a simple and cost-effective design.