Hello there, I understand that your father is having long standing diabetes and hypertension (High blood pressure). I do not know what treatment he is on. However both diabetes and hypertension are known to cause kidney problems both independently and together. Blood creatinine levels is a test to detect kidney function which changes with many factors like age, medications and any other medical conditions (like urinary infection or dehydration). From the creatinine levels mentioned by you it is definitely out of normal range and needs urgent visit to your physician to find the cause and also change or stop any medications that your father is currently taking. After assessing the cause your physician may refer your father to a nephrologist or urologist if required. Thanks