The BTA TRAK assay is a quantitative sandwich format enzyme immunoassay performed in a reference laboratory. It measures levels of human complement factor H-related protein (hCFHrp) which is similar to human complement factor H. Test characteristics reveal an overall sensitivity of 68% to 77.5% and a specificity of 50%-75%. Retrospective analysis of urine specimens employing hazard analysis suggests that BTA TRAK may have a role as a quantitative diagnostic marker in monitoring bladder cancer patients. Prospective studies are required to validate this application and other uses of the BTA TRAK assay in the management of bladder cancer patients.