A device for sampling blood from the skin of a patient by puncture. The device includes one or more lancets for lancing the skin and a fluid-conducting plate unit for transporting blood from the lancing wound. The plate unit has one or more channels for conducting fluid to one or more target locations. Preferably there is a first channel for conducting away a first portion of fluid that contains more of a fluid that is emitted initially (initial fluid) from the puncture wound and a second channel for conducting a second portion of fluid that contains less of the initial fluid from the puncture wound. Blood is drawn into the channels by capillary force. The device can be used to lance the skin and obtain a representative sample of blood with relatively simple procedures.