I suggest that you ask to have a blood test for a serum creatinine and then use this to calculate your estimated glomerular filtration rate (eGFR). You should also ask for a urine test for blood, protein and infection. Using these tests, you can determine if there is kidney disease present. You can access the equations used to calculate your eGFR on our web site at: https://www.kidney.org/professionals/KDOQI/gfr_calculator
Once these tests are done, you can consult with your physician and ask him or her to explain the results.