In conclusion, notwithstanding issues relating to assay cost, the present data support simultaneous measurement of serum creatinine and cystatin C and calculation of a simple ratio (eGFRcyst/eGFRcreat) in all people with type 2 diabetes as a useful clinical test for the development of cardiorenal complications associated with mortality. The gene discussed is CST3; the disease is type 2 diabetes mellitus.