How to assess the kidney function of a person presenting in OPD with Type 2 or Type 1 diabetes mellitus and stage it on the basis of the most readily available clinical investigations, clinical examination, and history. What are the essential treatment options that should be kept in mind for every stage-related treatment of that patient, for example prevention of progression of chronic kidney disease, nephropathy, retinopathy, and other kidney-related issues and body wasting?