San Carlos, Calif.-based Natera Inc. has kicked off a prospective nationwide registry study for kidney transplant recipients to look at changes in biopsy usage and clinical outcomes associated with use of its Prospera kidney transplant rejection assay. The Proactive study, which will involve 3,000 kidney transplant patients from the time of surgery, will follow most patients for three years and a subset of high-risk patients for five years. The overarching goal of the study is to improve detection of active rejection and improve long-term patient outcomes with use of physician-prescribed Prospera.