Chronic kidney disease (CKD) is a serious health problem because of its potential development to renal failure. Recent studies show that Cystatin C is a more reliable and sensitive marker than traditional serum creatinine in detecting early CKD. Increasing demand for Cystatin C measurement to detect declining kidney function has prompted an urgent need for rapid, simple and sensitive detection methods. To help research scientists in this effort, a proprietary repertoire of monoclonal antibodies to Cystatin C has been expanded and a Cystatin Free Serum has been added.