We have presented a platform that combines paper microfluidics and laser-pyrolyzed electronics. We elucidated the formation of nanoscale graphenic domains upon laser-induced pyrolysis of cellulose and found that the LIG-E not only conserves the microscale structure and mesoporous nature of cellulose fibers, but can also retain the wetting and wicking behaviour due to the oxygen-rich surface functional groups. The process enables the independent design of capillary and electronic current pathways and overlays. The LIG-E exhibits high electrochemical porosity and electron transfer rates. We have demonstrated two clinically relevant assays using the lateral and vertical flow configurations. The former is a flow injection analysis device for alkaline phosphatase detection of serum samples, showing high throughput (> 1 assay per minute) and accurate calibration-free quantification by standard addition.