Breath test

A breathing gas test ( also called shortened breath test ) is a diagnostic method, in which the exhaled air of a patient is analyzed. Applications include detection of Helicobacter pylori with the 13C -urea breath test and incompatibilities of individual sugars (mainly lactose intolerance ) with the hydrogen breath test, or even the conclusion of respiratory gas concentrations on blood concentrations, for example in the breath alcohol determination.

In principle, many respiratory function tests similar gas: It is made an output sample of the exhaled air, and then administered to a test substance and then removed one or more additional samples of exhaled air. The different composition of the air before and after administration of the test substance can be inferred indirectly to certain pathological changes in the gastrointestinal tract.

Examples of respiratory gas tests

13C -urea breath test

For the 13 C-urea breath test the patient is administered urea, which is labeled with the stable (ie, non-radioactive ) carbon isotope 13C. Directly in front of the urea dose and 30 minutes after a sample of the exhaled air is taken in each case. In addition, the patient is given just prior to administration of the urea solution, an acidic beverage to close the pylorus and thus to ensure that the urea test solution as long as possible remains in the stomach. If the patient is infected with Helicobacter pylori, the bacteria will cleave the urea in the stomach wall, inter alia, carbon dioxide ( CO2). This is exhaled and determined the proportion of 13CO2 total CO2 before and after urea administration with an infrared spectrometer.

Hydrogen breath test

When hydrogen breath test, the hydrogen content of the basal exhaled air is first determined. A large quantity of a particular sugar administered in aqueous solution - then the patient is - depending on the issue. The hydrogen content of the exhaled air is then at short intervals ( 5-15 minutes) was determined again. Existing in the intestinal bacteria are capable of absorbing the sugar and to metabolize. This produces hydrogen gas (H2), which is exhaled by the lungs.

Alcohol test

When alcohol test, the alcohol content is determined in the exhaled air (eg with a Alcotest device). Since an accurate inference of the alcohol concentration in the breath on the alcohol concentration in the blood without further information is possible (see respiratory gas analysis), a blood test must be performed to validate upon confirmation of a suspicion.