Test element for analyzing sample material

• US 20050141592A1
• Filed: 12/15/2004
• Published: 06/30/2005
• Est. Priority Date: 12/16/2003
• Status: Abandoned Application

• Current Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Roesicke, Bernd, Ocvirk, Gregor, Kalveram, Stefan
• Application Number:
  US11/013,048
• Publication Number:
  US 20050141592A1
• Time in Patent Office: Days
• US Class Current: 374/185
• CPC Class Codes: B01L 2300/0825 Test strips
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: G01N 33/86 involving blood coagulating time or factors, or their receptors

Abstract

A test element for analysing sample material such as blood or urine comprising a test carrier which has an analytical area to which sample material can be applied, and a heating element in heat conducting contact with the analytical area. The heating element integrated into the test carrier is formed by a thermistor which self-heats and self-regulates to a preset target temperature when current flows through it.

Claims

1. A test element for analysing sample material such as blood or urine comprising:

a test carrier which has an analytical area to which sample material can be applied; and

a heating element in heat conducting contact with the analytical area, wherein the heating element integrated into the test carrier is formed by a thermistor which self-heats and self-regulates to a preset target temperature when current flows through it.

2. The test element of claim 1, wherein the thermistor as a cold conductor exhibits a sharp, non-linear increase in resistance in the region of the target temperature as the temperature increases.

3. The test element of claim 1, wherein the thermistor is designed as a heating field.

4. The test element of claim 3, wherein the thermistor is designed as a thin layer heating field.

5. The test element of claim 1, wherein the thermistor is integrated as a flat structure into the test carrier.

6. The test element of claim 5, wherein the thermistor is integrated layer-wise by a coating or printing process.

7. The test element of claim 1, wherein the thermistor is formed from a composite material comprising a binding agent and electrically conductive components incorporated therein.

8. The test element of claim 7, wherein the composite material goes through a phase transition at the target temperature which influences the electrical conductivity.

9. The test element of claim 7, wherein the binding agent is composed of monomers or polymers.

10. The test element of claim 7, wherein the conductive components comprise particles of carbon black, carbon fibres, metal threads or conductive polymer particles.

11. The test element of claim 1, wherein the test carrier is provided as a disposable article for single analyses.

12. The test element of claim 1, wherein the test carrier is formed by a flat substrate.

13. The test element of claim 12, wherein the flat substrate comprises a test strip.

14. The test element of claim 13, wherein the test strip is a composite foil part.

15. The test element of claim 1, wherein the analytical area is at least partially bounded by the thermistor.

16. The test element of claim 1, wherein the analytical area is formed by a reaction field coated with dry chemicals which responds to an analyte in the applied sample material.

17. The test element of claim 1, wherein in order to preheat the sample material, the thermistor extends beyond the analytical area to a sample supply channel of the test carrier.

18. The test element of claim 1, wherein the thermistor also forms a temperature sensor for determining the analytical temperature by means of a resistance measurement.

19. The test element of claim 1, wherein connections for a voltage source that are connected with the thermistor are arranged on the test carrier.

20. The test element of claim 19, wherein the connections for the voltage source are formed by conducting paths.

21. The test element of claim 1, wherein the target temperature is in the range between about 25 to about 50°

C.

22. The test element of claim 16, wherein the target temperature is in the range between about 30 to about 40°

C.

23. The test element of claim 1, wherein the deviation from the target temperature is less than about 1°

C.

24. The test element of claim 1, wherein the analytical area is connected to the thermistor by an intermediate foil in a heat-conducting manner.

25. The test element of claim 1, wherein the thermistor as a flat structure covers only a partition of the test carrier including the analytical area and leaving free the inlet and outlet of a sample supply channel.

26. A measuring instrument for processing the test element as claimed in claim 1 comprising a voltage source, a slot for receiving a test element, a measuring and evaluation unit and a display unit.

27. The measuring instrument of claim 26, wherein said measuring instrument comprises a portable blood sugar measuring instrument or a portable blood coagulation measuring instrument