The inherent centrifugation capability of the so-called ‘Lab-on-a-Disc’ (LoaD) platforms is widely used for blood processing during sample preparation. Here we introduce a valving technique which ena-bles rotational control of paper wetting to actuate dissolvable film (DF) valves. This mechanism is applied to the separation of whole blood into its chief constituents; plasma, leukocytes and erythrocytes.