In Indian scenario, the incidence of diabetes mellitus is very high and diabetic nephropathy is its common complication. Blood urea and serum creatinine are common tests used to assess renal functions. Serum creatinine can be raised due to non renal causes.

By the time, creatinine levels start elevating due to renal cause 50% of renal functions are already gone. Are there any markers which can assess renal functions before starting of renal damage?