METHOD AND DEVICE FOR GENERATING A CORRECTED VALUE OF AN ANALYTE CONCENTRATION IN A SAMPLE OF A BODY FLUID

• US 20160011178A1
• Filed: 09/18/2015
• Published: 01/14/2016
• Est. Priority Date: 03/19/2013
• Status: Active Grant

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Inventors: Hoenes, Joachim, Ringemann, Christian, Weller, Andreas
• Granted Patent: US 10,900,957 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 21/75 Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated systems in which material is burnt in a flame or plasma G01N21/72, G01N21/73
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771
• CPC Class Codes: G01N 33/5094 for blood cell populations red blood cells G01N33/80
• CPC Class Codes: G01N 33/525 Multi-layer analytical elements
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: G01N 33/66 involving blood sugars, e.g. galactose

Abstract

Methods for detecting an analyte in a body fluid are described as well as devices and systems adapted for performing such methods. In embodiments of the method, a sample of body fluid is applied to a test element having at least one test field including at least one test material that is adapted to change at least one measurable property in the presence of the analyte. The test element further includes a capillary to guide the sample across said test field in a flow direction. The test element also includes first and second measurement locations offset from each other in the flow direction. The measurable property is measured in at least one first measurement location, providing at least one first measurement value, and it is measured in at least one second measurement location, providing at least one second measurement value. The analyte is detected by using an evaluation algorithm having at least two input variables, wherein at least one first input variable of the at least two input variables includes 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 includes information relating to an analyte-induced change of the measurable property of the test material in at least part of the test field.

Claims

1. A method for detecting an analyte in a body fluid, the method having the following steps:

a) applying a sample of the body fluid to a test element, said test element comprising at least

(i) a test field comprising at least one test material adapted to change at least one measurable property in the presence of the analyte,

(ii) a capillary element adapted to guide the sample across said test field in a flow direction,

(iii) a first and a second measurement location within said test field, wherein the second measurement location is offset from the first measurement location in the flow direction;

b) measuring the measurable property in said at least one first measurement location, thereby generating at least one first measurement value;

c) measuring the measurable property in said at least one second measurement location, thereby generating at least one second measurement value;

d) detecting the analyte by using an evaluation algorithm having at least two input variables, wherein

(i) at least one first input variable of the at least two input variables includes an information on a difference between the first measurement value and the second measurement value, and

(ii) at least one second input variable of the at least two input variables includes a measurement information on an analyte-induced change of the measurable property of the test material in at least part of the test field,

wherein the test material performs at least one optically or electrochemically detectable detection reaction in the presence of the analyte.

2. The method according to claim 1, wherein the measurement information on an analyte-induced change of the measurable property of the test material in at least part of the test field is generated by one or more of the procedures selected from the group consisting of using the first measurement value as the measurement information, using the second measurement value as the measurement information, using an average value of the first measurement value and the second measurement value as the measurement information, and measuring an 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 wherein the third measurement value is used as the measurement information.

3. The method according to claim 1, wherein the measurement information used in step d) (ii) is a measurement value generated at a measurement location located within the first half of the test field in view of the flow direction.

4. The method according to claim 1, wherein method steps b) and c) are performed at one of a predetermined time span after application of the sample of the body fluid to the test element, and at a point in time at which a measurement curve indicating the measurable property as a function of time fulfills at least one predetermined condition comprising at least one threshold condition wherein a slope of the measurement curve is below or above a predetermined threshold.

5. The method according to claim 1, wherein the evaluation algorithm comprises a one-step evaluation algorithm, and the first input variable and the second input variable are simultaneously used for deriving the concentration of the analyte in the body fluid by using at least one predetermined calibration curve, the predetermined calibration curve indicating the concentration of the analyte as a function of the two input variables.

6. The method according to claim 1, wherein the evaluation algorithm comprises at least two separate steps, wherein in a first step of the evaluation algorithm, an estimate value of the concentration is derived from the second input variable by using at least one predetermined first calibration curve, the predetermined first calibration curve indicating an uncorrected concentration of the analyte as a function of the second input variable, and wherein in a second step of the algorithm, the estimate value of the concentration is corrected by applying at least one correction algorithm to the estimate value, the correction algorithm providing a correction to the estimate value by using the first input variable.

7. The method according to claim 6, wherein the sample of the body fluid is blood, in the first step of the algorithm, an estimate value of a glucose concentration is generated, and in the second step of the algorithm, a correction of the estimate value for an actual hematocrit of the blood is provided, thereby generating an information on the glucose concentration in the blood without determining the actual hematocrit of the blood.

17. A test system for detecting an analyte in a body fluid, the test system comprising

a) at least one test device according to one of the preceding claims referring to a test device, and

b) at least one test element, wherein the test element has at least one test field having at least one test material adapted to change at least one measurable property in the presence of the analyte and having a capillary element adapted to guide the sample across the test field in a flow direction, and wherein the test material performs at least one optically or electrochemically detectable detection reaction in the presence of the analyte.

8. A method for detecting an analyte in a body fluid, the method having the following steps:

a) applying a sample of the body fluid to a test element, said test element comprising at least

(i) a test field having at least one test material adapted to change at least one measurable property in the presence of the analyte,

(ii) a capillary element adapted to guide the sample across said test field in a flow direction,

(iii) at least one single measurement location within said test field;

b) measuring the measurable property in said single measurement location, thereby generating at least one measurement value;

c) detecting the analyte by using an evaluation algorithm having the measurable property as an input variable,

wherein said single measurement location is located within the first third of the test field as determined from the application site, and wherein the test material performs at least one optically or electrochemically detectable detection reaction in the presence of the analyte.

9. A test device for detecting an analyte in a body fluid, wherein the test device contains

a) at least one receptacle for receiving at least one test element, the test element having

(i) at least one test field having at least one test material adapted to change at least one measurable property in the presence of the analyte and

(ii) at least one capillary element adapted to guide the sample across the test field in a flow direction,

b) wherein the receptacle is adapted to locate the test element in at least one application position in which a sample of the body fluid is applicable to the test element,

c) wherein the device further contains at least one detector for measuring the measurable property, wherein the detector is adapted to measure the measurable property

(i) in at least one first location of the test field, thereby generating at least one first measurement value,

(ii) in at least one second location of the test field, thereby generating at least one second measurement value, wherein the second location is offset from the first location in the flow direction,

d) wherein the test device further comprises at least one evaluation unit adapted to determine the concentration of the analyte by using an evaluation algorithm having at least two input variables,

(i) wherein at least one first input variable of the at least two input variables includes an information on a difference between the first measurement value and the second measurement value, and

(ii) wherein at least one second input variable of the at least two input variables includes a measurement information on an analyte-induced change of the test material in at least part of the test field,

wherein the test material performs at least one optically or electrochemically detectable detection reaction in the presence of the analyte.

10. The test device according to claim 9, wherein the test device is adapted to perform the method according to one of the preceding method claims.

11. The test device according to claim 9, 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.

12. The test device according to claim 9, wherein

the test device is adapted to measure the analyte-induced change of the measurable property in at least one third location of the test field, thereby generating at least one third measurement value,

the third measurement value is used as the measurement information,

the test field extends in the flow direction, and wherein

the third location is located within the first 99% of the test field in view of the flow direction.

13. The test device according to claim 12, wherein the third location is located within the first third of the test field in view of the flow direction.

14. The test device according to claim 13, wherein the third location is located within the first quarter of the test field in view of the flow direction.

15. The test device according to claim 9, wherein the test device further comprises at least one temperature sensor for determining an ambient temperature.

16. A test device for detecting an analyte in a body fluid, wherein the test device contains

a) at least one receptacle for receiving at least one test element, the test element having

(i) at least one test field having at least one test material adapted to change at least one measurable property in the presence of the analyte and

(ii) at least one capillary element adapted to guide the sample across the test field in a flow direction,

b) wherein the receptacle is adapted to locate the test element in at least one application position in which a sample of the body fluid is applicable to the test element,

c) wherein the device further contains at least one detector for measuring the measurable property, wherein the detector is adapted to measure the measurable property in at least one single measurement location of the test field, thereby generating at least one measurement value,

d) wherein the test device further comprises at least one evaluation unit adapted to determine the concentration of the analyte by using an evaluation algorithm having at least said measurement value as an input variable,

wherein the detector is adapted to measure the measurable property within the first third of the test field, and wherein the test material performs at least one optically or electrochemically detectable detection reaction in the presence of the analyte.