Abstract: The invention relates to a system for the detection of biomarkers in the air exhaled from patient's lungs, comprising a leak-proof multipass cell provided with a gas inlet and outlet, into which a sample of the exhaled air is introduced by means of a pneumatic system, wherein the multipass cell is provided with one laser whose light beam is directed along a coaxial optical path to the multipass cell comprising at least two concave mirrors arranged in parallel and a gas inlet and outlet, which is filled with a sample of the analyzed exhaled gas, wherein the pneumatic system is connected to the gas inlet and outlet of the multipass cell by means of lines supplying the exhaled air, characterized in that the pneumatic system comprises a preliminary container of the exhaled air comprising an air inlet and outlet, wherein the air outlet additionally comprises an air flow meter, the preliminary container is further connected by an elastic line supplying the air to the multipass cell on one side and on the other side