Abstract: An assay device may include a first cylinder that includes a first end that is closed and a second, opposite end that is open. The first cylinder may include one or more reservoirs that are compressible and store one or more reagents. The device may include a test chamber to which the reservoirs are connected, and in which the sample can be inserted to perform the assay; and a second cylinder that includes a third end that is closed and a fourth, opposite end that is open. The fourth end may fit within the second end to enable the second cylinder to be attached to, and rotate within, the first cylinder. The third end may include a member that compresses the reservoirs, in a predetermined order, as the second cylinder is rotated within the first cylinder to cause the reagents to flow, to the test chamber, in the predetermined order.