And about this question

It is important to recognize whether hyperuricemia is secondary to renal failure OR renal failure is due to uric acid nephropathy.

In these cases based on Up-to-date, Overexcretion of uric acid can be documented in many patients by a uric acid-to-creatinine ratio (mg/mg) above 1 on a random urine specimen (although urate nephropathy usually occurs in uric acid levels more than 15 mg/dl).