A microfluidic sample processing disk, comprising: a body comprising first and second major surfaces; a plurality of fluid structures, wherein each fluid structure of the plurality of fluid structures comprises: an input well comprising an opening; a process chamber located radially outward of the input well, wherein the process chamber comprises a void formed through the first and second major surfaces (52, 54) of the body; and a delivery channel connecting the input well to the process chamber, wherein the delivery channel comprises an outer channel formed in the first major surface of the body; a first annular cover attached to the first major surface of the body; a second annular cover attached to the second major surface of the body; characterized in that the delivery channel comprises an inner channel formed in the second major surface of the body, and a via formed through the first and second major surfaces (52, 54) of the body, wherein the via connects the inner channel to the outer channel, wherein the vias and the process chambers of the plurality of fluid structures define annular rings on the body; the first annular cover defines the vias, the outer channels, and the process chambers in connection with the first major surface of the body; the second annular cover defines the process chambers of the plurality of fluid structures in connection with the second major surface of the body, wherein an inner edge of the second annular cover is located radially outward of the annular ring defined by the vias of the plurality of fluid structures; and that the sample processing disk further comprises a central cover attached to the second major surface of the body, the central cover defining the inner channels and the vias in connection with the second major surface of the body, wherein an outer edge of the central cover is located radially outward of the annular ring defined by the vias of the plurality of fluid structures. a body comprising first and second major surfaces; a plurality of fluid structures, wherein each fluid structure of the plurality of fluid structures comprises: an input well comprising an opening; a process chamber located radially outward of the input well, an input well comprising an opening; a process chamber located radially outward of the input well, wherein the process chamber comprises a void formed through the first and second major surfaces (52, 54) of the body; and a delivery channel connecting the input well to the process chamber, wherein the delivery channel comprises an outer channel formed in the first major surface of the body; a first annular cover attached to the first major surface of the body; a second annular cover attached to the second major surface of the body; characterized in that the delivery channel comprises an inner channel formed in the second major surface of the body, and a via formed through the first and second major surfaces (52, 54) of the body, wherein the via connects the inner channel to the outer channel, wherein the vias and the process chambers of the plurality of fluid structures define annular rings on the body; the first annular cover defines the vias, the outer channels, and the process chambers in connection with the first major surface of the body; the second annular cover defines the process chambers of the plurality of fluid structures in connection with the second major surface of the body, wherein an inner edge of the second annular cover is located radially outward of the annular ring defined by the vias of the plurality of fluid structures; and that the sample processing disk further comprises a central cover attached to the second major surface of the body, the central cover defining the inner channels and the vias in connection with the second major surface of the body, wherein an outer edge of the central cover is located radially outward of the annular ring defined by the vias of the plurality of fluid structures. a delivery channel connecting the input well to the process chamber, wherein the delivery channel comprises an outer channel formed in the first major surface of the body; a first annular cover attached to the first major surface of the body; a second annular cover attached to the second major surface of the body; the delivery channel comprises an inner channel formed in the second major surface of the body, and a via formed through the first and second major surfaces (52, 54) of the body, wherein the via connects the inner channel to the outer channel, wherein the vias and the process chambers of the plurality of fluid structures define annular rings on the body; the first annular cover defines the vias, the outer channels, and the process chambers in connection with the first major surface of the body; the second annular cover defines the process chambers of the plurality of fluid structures in connection with the second major surface of the body, wherein an inner edge of the second annular cover is located radially outward of the annular ring defined by the vias of the plurality of fluid structures; and that the sample processing disk further comprises a central cover attached to the second major surface of the body, the central cover defining the inner channels and the vias in connection with the second major surface of the body, wherein an outer edge of the central cover is located radially outward of the annular ring defined by the vias of the plurality of fluid structures.