The invention refers to method for selectively binding and separating at least one component from whole blood or a body fluid, whereby the blood or body fluid is allowed to pass through a rigid integral separation matrix without being excluded therefrom. The matrix has a porous structure with a pore size raging from 5 micron to 500 micron as well as an active surface ranging from 0.5 cm.sup.2 to 10 m.sup.2, and the surface is able to bind such components.