DETERMINATION OF ALCOHOL CONTENT IN BLOOD

摘要

The alcohol concentration in the blood is determined by analysing exhaled air. Air is exhaled through a tube past a sensor in an alcohol measuring device. Measurements are conveyed to an indicating device only when they are higher than all previous measurements during the test. A flow measuring device measures the volumetric flow of exhaled air and terminates the test when a preset flow has passed, when the indicating device displays the highest alcohol measurement so far recorded. The preset flow is selected to ensure that the test subject takes at least one deep breath during the test so that the results can not be falsified by deliberate shallow breathing.