CST3 and type 2 diabetes mellitus: The first phase of the C3 initiative which is described in this protocol seeks to improve the appropriate use of universal testing for CKD among patients with type 2 diabetes (T2D), hypertension or cardiovascular disease in primary care through the establishment of a triple-marker screen for CKD: creatinine-based eGFR, cystatin C-based eGFR, and albuminuria assessed by the ACR.