A breakthrough in the control of fluid flow in paper-based devices has been achieved by a team of researchers. Their method involves a tunable shunt that diverts fluid into an absorbent pad-based channel to delay fluid progress through a porous channel. The length and thickness of the shunt can be adjusted to achieve reproducible delays ranging from 3 to 20 minutes. To further understand the mechanism, a simple electrical circuit model was developed, which successfully predicted the delays in the system. The shunts were then incorporated into a pointof-care compatible folding card device for the sequential delivery of fluids to a detection zone using biochemical reagents for the amplified detection of the malaria protein PfHRP2. This novel tunable shunt has opened up new possibilities for paper microfluidic devices, providing a way to precisely control fluid flow and delivery.