A device and method for acquiring tissue or fluid. The device includes an instrument for acquiring tissue or fluid, and a pump. The instrument has a proximal end and a distal end at which the tissue or fluid is first acquired. The pump is connected to the proximal end of the instrument for applying negative pressure for drawing in the tissue or fluid. The pump has a switch for adjusting the amount of pressure. The method includes inserting an instrument into the site of the tissue or fluid to be acquired and exerting a controlled amount of adjustable negative pressure through the instrument to draw back into or onto the instrument the tissue or fluid being acquired.