Method and device for generating a corrected value of an analyte concentration in a sample of a body fluid

Abstract

Methods, devices and systems for detecting an analyte in a body fluid are described. A sample of body fluid is applied to a test element having a test field including a test material adapted to change a measurable property in the presence of the analyte. The test element includes a capillary to guide the sample across said test field. The measurable property is measured in a first measurement location providing a first measurement value, and in a second measurement location providing a second measurement value. The analyte is detected by using an evaluation algorithm having at least a first input variable including a difference between the first measurement value and the second measurement value, and at least a second input variable including information relating to an analyte-induced change of the measurable property of the test material in at least part of the test field.

What is claimed is: 
     
         1 . A test element for detecting an analyte in a sample of body fluid, comprising:
 a test field comprising a continuous test material, the test material having at least one measurable property which is changed in the presence of the analyte in the sample, said test material including a first measurement location and a second measurement location; and   a capillary element configured to guide the sample across said test field in a flow direction over both the first and second measurement locations, the second measurement location being offset from the first measurement location in the flow direction,   the test material at the first measurement location being adapted to provide in response to contact with the analyte a first change of the at least one measurable property of the test material at the first measurement location, and   the test material at the second measurement location being adapted to provide in response to contact with the analyte a second change of the at least one measurable property of the test material at the second measurement location.   
     
     
         2 . The test element according to  claim 1  in which the first and second measurement locations include the same test material. 
     
     
         3 . The test element according to  claim 2  in which the test material comprises at least one enzyme adapted for performing at least one enzymatic reaction on the analyte causing the change of the at least one measurable property of said test material in the presence of the analyte. 
     
     
         4 . The test element according to  claim 3  in which the at least one enzyme in the test material performs an optically or electrochemically detectable detection reaction at the first measurement location and at the second measurement location. 
     
     
         5 . The test element according to  claim 1  and in which said test material includes a third measurement location located within the test field. 
     
     
         6 . The test element according to  claim 5  wherein the third measurement location is located within the first third of the test field in view of the flow direction. 
     
     
         7 . The test element according to  claim 6 , wherein the third measurement location is located within the first quarter of the test field in view of the flow direction. 
     
     
         8 . The test element according to  claim 5  in which the first, second and third measurement locations include the same test material. 
     
     
         9 . A test element for detecting an analyte in a sample of body fluid, comprising:
 a test field comprising a test material, said test material having at least one measurable property which is changed in the presence of the analyte in the sample; and   a capillary element comprising at least one test material at a first measurement location and at least another test material at a second measurement location, the said capillary element being configured to guide the sample across said test field in a flow direction over both the first and second measurement locations, the second measurement location being offset from the first measurement location in the flow direction,   the test material at the first measurement location being adapted to provide in response to contact with the analyte a first change of the at least one measurable property of the test material at the first measurement location, and   the test material at the second measurement location being adapted to provide in response to contact with the analyte a second change of the at least one measurable property of the test material at the second measurement location.   
     
     
         10 . The test element according to  claim 9  in which said test material comprises at least one enzyme adapted for performing at least one enzymatic reaction on the analyte causing the change of the at least one measurable property of said test material in the presence of the analyte. 
     
     
         11 . A test device for detecting an analyte in a body fluid, comprising:
 at least one receptacle receiving at least one test element according to  claim 1 , the receptacle being adapted to locate the test element in at least one application position in which the sample of the body fluid is applicable to the test element;   at least one detector for measuring the measurable property, said detector being adapted to measure the measurable property in at least one first measurement location of the test field, thereby generating at least one first measurement value, and in at least one second measurement location of the test field, thereby generating at least one second measurement value; and   at least one evaluation unit adapted to determine the concentration of the analyte.   
     
     
         12 . The test device according to  claim 11  in which the first and second measurement locations include the same test material. 
     
     
         13 . The test device according to  claim 11  in which said test material comprises at least one enzyme adapted for performing at least one enzymatic reaction on the analyte causing the change of the at least one measurable property of said test material in the presence of the analyte, the at least one enzyme in the test material performing an optically or electrochemically detectable detection reaction at the first measurement location and at the second measurement location. 
     
     
         14 . The test device according to  claim 11  in which said evaluation unit is adapted to determine the concentration of the analyte by using an evaluation algorithm having at least two input variables, at least one first input variable of the at least two input variables including an information on a difference between the first measurement value and the second measurement value, and at least one second input variable of the at least two input variables including a measurement information on an analyte-induced change of the test material in at least part of the test field. 
     
     
         15 . The test device according to  claim 14 , wherein the at least one first input variable includes an information on a gradient of measurement values over at least part of the test field. 
     
     
         16 . The test device according to  claim 14 , wherein the test device is adapted to measure the analyte-induced change of the measurable property in at least one third measurement location of the test field, thereby generating at least one third measurement value, the third measurement value being used as the measurement information. 
     
     
         17 . The test device according to  claim 16  in which the first, second and third measurement locations include the same test material. 
     
     
         18 . The test device according to  claim 14 , wherein the test device further comprises at least one temperature sensor for determining an ambient temperature. 
     
     
         19 . The test device according to  claim 14 , wherein the measurement information on an analyte-induced change of the measurable property of the test material in at least part of the capillary element is generated by using an average value of the first measurement value and the second measurement value as the measurement information. 
     
     
         20 . The test device according to  claim 14  including correcting the analyte detection based on the presence of particulate matter in the sample. 
     
     
         21 . A test system for detecting an analyte in a body fluid, the test system comprising
 at least one test device according to  claim 11 ; and   at least one test element according to  claim 1 ,   wherein the test material performs at least one optically or electrochemically detectable detection reaction in the presence of the analyte.