A suction applying device (10) for applying suction to a sampling unit (50) for sampling bodily fluid, wherein the suction applying device comprises a syringe body (12) with a hollow interior (14) and a piston (20) movable inside the hollow interior of the syringe body. The syringe body has a rear end (16) through which a piston rod (21) connected to the piston extends outside of the syringe body and by means of which the piston can be moved, and a front end (18) opposite the rear end. The suction applying device further comprises a connection arrangement (130) configured for connection of a sampling unit, wherein the connection arrangement is located at the front end of the syringe body. The suction applying device also comprises a first conduit (40) having a rear opening (41) connecting the first conduit to a rear portion (14b) of the hollow interior, in which rear portion a sub-pressure is created when the piston is moved forward inside the hollow interior, and a front opening (42) by means of which the first conduit is connectable to a sampling unit. The suction applying device also comprises a second conduit (46) that connects a front portion (14a) of the hollow interior with the exterior of the syringe body, and which front portion is located between the piston and the front end of the syringe body. Also disclosed is an apparatus for sampling bodily fluid, comprising a suction applying device and a sampling unit, as well as a method for detecting a component in a bodily fluid.L'invention concerne un dispositif d'application d'aspiration (10) pour appliquer une aspiration à une unité d'échantillonnage (50) afin d'échantillonner un fluide corporel, le dispositif d'application d'aspiration comprenant un corps de seringue (12) ayant un intérieur creux (14) et un piston (20) mobile dans l'intérieur creux du corps de seringue. Le corps de seringue a une extrémité arrière (16) à travers laquelle une tige de piston (21) reliée au piston s'étend à l'extérieur du corps
