A body fluid sampling system for use on a tissue site includes an electrically powered drive force generator. A penetrating member is operatively coupled to the force generator. The force generator moves the member along a path out of a housing having a penetrating member exit, into the tissue site, stops in the tissue site, and withdraws out of the tissue site. A cartridge houses the penetrating member. The cartridge has first and second seals coupled to the penetrating member to maintain a sterile environment around a portion of the penetration member prior to penetrating member actuation.