A test system for analyzing a sample of a bodily fluid is provided and comprises: at least one test strip comprising at least one capillary channel comprising an inlet opening configured to receive the sample; a vent opening configured to provide an air vent to the capillary channel; and at least one zone consisting of a detection zone and a reagent zone; at least one measuring device configured for interacting with the test strip, the measuring device comprising at least one sealing element for hermetically sealing the vent opening from an ambient atmosphere; and at least one suction device adapted to provide an underpressure to the vent opening; wherein the measuring device further comprises at least one valve or is connectable to the valve, wherein the valve is configured to vent the vent opening of the test strip when the measuring device interacts with the test strip.