A device for sampling body fluid includes a housing having a sleeve at a forward end thereof which is displaceable in response to being pressed against a user's skin to trigger the firing of a lancer. After the lancet is removed from the incision, the sleeve is repeatedly pressed against the skin to depress a ring of body tissue in surrounding relationship to the incision to express body fluid outwardly through the incision. A pusher member is then actuated to push a capillary tube through a front end of the housing for drawing-in body fluid. The lancet is a disposable lancet which includes a body supporting a skin-lancing member and the capillary tube. The disposable lancet passes through an upper end of a lancet carrier when being installed or removed. The device cannot be armed until the disposable lancet is installed in the housing, because the capillary tube functions to push a safety device to a non-safety position.