Lysing may include agitating a specimen in a chamber along with a medium that includes a particulate lysing material that has an affinity for a biological material. Lysing material may include beads or other material which may be coated that facilitates binding. The medium may include a fluid with a high salt or low pH level. Binding of biological materials to solid surfaces may be induced by particular media. The biological material may be eluted by lowering a concentration of salt or increasing a pH level. Lysing materials with two or more different affinities may be employed. Lysing materials may include particles of different sizes. Heating may be used. Lysing may be performed in a flow through apparatus. Surfaces of solid materials may be modified to capture bacteria with high cell wall lipid content.