Patent ID: 7524641

Claim:
A method of separating at least one target component from a biological sample, said method comprising a. placing said biological sample into a separation container, said separation container comprising a focusing device, having an axial bore passage and being capable of vertical movement within said separation container upon centrifugation and a specific density a set of selection microbeads having at least one target affinity binding agent bound to their surfaces, said at least one target affinity binding agent having a binding affinity for said at least one target component within said biological sample and a negative selection binding agent having a binding affinity for a component other than said target component within said biological sample, such that a complex or conjugate is formed between said negative selection binding agent and said component other than said target component within said biological sample on contact with said biological sample, wherein the specific density of said focusing device is substantially equal to the density of said set of selection microbeads and the specific density of said complex or conjugate formed between said negative selection binding agent and said component other than said target component within said biological sample is different to that of said focusing device and said set of selection microbeads b. centrifuging said separation container containing said biological sample to densitometrically separate components of said sample into layers such that separation of said set of selection microbeads and said complex or conjugate formed between said negative selection binding agent and said component other than said target component within said biological sample is induced, wherein an elongated target layer comprising said set of selection microbeads bound to said at least one target component is located within said axial bore passage of said focusing device and wherein said complex or conjugate formed between said negative selection binding agent and said component other than said target component within said biological sample is absent from said axial bore passage of said focusing device after centrifugation; and c. aspirating said elongated target layer to remove said at least one target component from said separation container.