METHOD FOR DETECTING HELICOBACTER PYLORI

Abstract

A method through which a more rapid detection of Helicobacter pylori in a gaseous sample is practicable, in which the .sup.13C content is measured only until a minimum number of measurement values of the .sup.13C content meets a standard deviation to be specified. The known .sup.13C urea breath test has become established for clinical diagnosis for detecting Helicobacter pylori infections and known methods for detecting Helicobacter pylori provide that each method step corresponds to a fixed, specified time, which is disadvantageous, especially for performing a large number of such tests.

Claims

1. A method for detecting Helicobacter pylori by means of non-dispersive infrared spectroscopy with use of .sup.13C-labeled urea, comprising: firstly a measurement chamber is flushed with CO.sub.2-free gas; a gaseous sample is admitted into the measurement chamber; the sample distributes itself homogeneously and the .sup.13C content in the sample is measured; and the measurement of the .sup.13C content is only carried out until a minimum number of measurement values of the .sup.13C content meets a standard deviation to be specified.

2. The method as claimed in claim 1, wherein the .sup.13C content in the sample is already measured during the homogenization of the sample in the measurement chamber.

3. The method as claimed in claim 1, wherein the first recorded measurement values of the .sup.13C content in the sample which meet the standard deviation are used as measurement results.

4. The method as claimed in claim 1, wherein as soon as the .sup.13C measurement values meet the standard deviation of at most 1‰, the .sup.13C measurement values are assessed as measurement results.

5. The method as claimed in claim 1, wherein the flushing of the measurement chamber and the admission of the sample into the measurement chamber is performed only until a threshold value of the CO.sub.2 content or the .sup.12C content in the measurement chamber, to be specified, is reached.

6. The method as claimed in claim 1, wherein the CO.sub.2 content or the .sup.12C content in the measurement chamber is measured during the flushing of the measurement chamber and during the admission of the sample into the measurement chamber.

7. The method as claimed in claim 1, wherein the measurement chamber is flushed with the CO.sub.2-free gas until the CO.sub.2 content in the measurement chamber is at most 0.1% and thereupon the sample is admitted into the measurement chamber.

8. The method as claimed in claim 1, wherein the sample is admitted into the measurement chamber until the CO.sub.2 volume content is at least 0.2%.

9. The method as claimed in claim 1, wherein the .sup.13C content and the CO.sub.2 content or .sup.12C content are determined by sensors which are read off by a control unit and the control unit compares the measurement values of the sensors with the threshold values to be specified.

10. The method as claimed in claim 1, wherein pumps and/or valves for regulating a gas flow respectively into and out of the measurement chamber are regulated by the control unit.

11. The method as claimed in claim 1, wherein the first 10 recorded measurement values of the .sup.13C content in the sample which meet the standard deviation are used as measurement results.

12. The method as claimed in claim 1, wherein the first 20 recorded measurement values of the .sup.13C content in the sample which meet the standard deviation are used as measurement results.

13. The method as claimed in claim 1, wherein as soon as the .sup.13C measurement values meet the standard deviation of at most 0.2‰, the .sup.13C measurement values are assessed as measurement results.

14. The method as claimed in claim 1, wherein the measurement chamber is flushed with the CO.sub.2-free gas until the CO.sub.2 content in the measurement chamber is at most 0.05% and thereupon the sample is admitted into the measurement chamber.

15. The method as claimed in claim 1, wherein the sample is admitted into the measurement chamber until the CO.sub.2 volume content is at least 0.5%.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0015] A preferred practical example of the method according to the invention is explained in more detail on the basis of a diagram below.

[0016] FIG. 1 is a graph of the variation of carbon content in a measurement chamber with time.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0017] In the diagram, the variation of the carbon content, in particular the .sup.13C content, in the measurement chamber with time during the method according to the invention is plotted. The y-axis represents in arbitrary units the relative content of the carbon in the measurement chamber.

[0018] In a first phase 10 of the method, the measurement chamber is filled with any gas and thus with any content of carbon or CO.sub.2. For example, a measurement for the detection of Helicobacter pylori had just been finished. In the second phase 11, the measurement chamber is flushed, i.e. prepared for the actual measurement method. For this a CO.sub.2-free gas is passed into the chamber and at the same time a pump which is connected to the chamber is switched on. Through the flushing and pumping, the carbon content in the measurement chamber decreases rapidly. Already during this second phase 11 of the method, the carbon content is determined by NDIR spectroscopy. As soon as the carbon content has gone below a defined threshold value, the flushing is ended by ending the admission of the CO.sub.2-free gas.

[0019] In the third phase 12 of the method, the breath sample of the person affected is passed into the measurement chamber. Since the CO.sub.2 content in the breath sample is high, the carbon content climbs rapidly in the third phase 12. In this phase also, the carbon content is determined by spectroscopy. As soon as the CO.sub.2, in particular the .sup.12C and/or .sup.13C, content meets a certain threshold value, the admission of the breath sample is also stopped by a valve being closed.

[0020] In the following fourth phase 13, a homogenization of the CO.sub.2-containing breath sample in the measurement chamber takes place. During the fourth phase 13, a specific measurement of the .sup.13C content (fifth phase 14) already takes place. Thus the fourth phase 13 passes smoothly into the fifth phase 14. If the .sup.13C measurement values already reveal that the deviations meet a preset standard deviation, these measurement values are already assessed as measurement results. Usually 10 to 20 such measurement results or points are recorded in order to achieve a reliable result concerning infection with Helicobacter pylori. After the fifth phase 14, the method can be continued according to the first phase 10.

LIST OF SYMBOLS

[0021] 10 1.sup.st phase [0022] 11 2.sup.nd phase [0023] 12 3.sup.rd phase [0024] 13 4.sup.th phase [0025] 14 5.sup.th phase