The basic idea is that cancer in the bladder will form a tumour, and some cells from that tumour will break off and pass out through the urine. The urine is mixed with a fluid that Pacific Edge created, which extracts the 'messenger RNA' (mRNA - a family of molecules that carry around information within a cell). Within the mRNA they look for signals of 5 different 'biomarkers' - specific sets of coding which show that this cell can or will do a certain task.
Through a series of chemical and biological processes, scientists can tell if the right combination of these 5 markers is present, which would indicate the cell is likely to be cancerous. It's an amazing process, unthinkable 20 years ago, and a technique that can be adapted to a number of cancers and genetic illnesses. They are seeing test results with 69-90% reliability, and a much lower risk of 'false positives' (detections when there is no cancer).
This means a large number of patients can get the test done painlessly and non-invasively, and only those with a heightened risk or a positive result need to experience the needle.