Abstract: A rotor unit for a centrifugal analyzer comprises a rotatably-driven circular rotor base; and a rotor head comprising a plurality of insert elements each having at least one chamber sample for the reception of a sample liquid, at least one measuring chamber radially outwardly from the associated sample chamber for the measurement of characteristic parameters for the detection of components of the sample, at least one liquid channel connecting the sample chamber with the measuring chamber and each insert element is releasably mounted on the rotor base at any one of a plurality of different selectable angular positions wherein the insert element is positionally stable when the rotor base is rotating.