Current blood and urine tests provide important information on the decline of kidney function; however, these tests are not useful for monitoring early events of PKD such as initial cyst growth and damage to neighboring tissue. Clearly, novel biomarkers of early cystic disease need to be discovered to develop appropriate clinical tests to monitor the progression of early stage PKD. These tests will be important to identify patients at risk of rapid progression and of need of therapeutic intervention and to monitor the effectiveness of the therapeutic drug. The PKD Biomarkers Repository will allow approved researchers to obtain blood and urine samples for biomarker discovery and development of appropriate biomarker assays for prognosis of early PKD.