Suggestive but nonspecific findings include a bland urine sediment and hyperuricemia disproportionate to the degree of renal insufficiency: Urate > 9 mg / dL (535.4 micromol / L) with serum creatinine < 1.5 mg / dL (132.6 micromol / L) Urate > 10 mg / dL (594.9 micromol / L) with serum creatinine 1.5 to 2 mg / dL (132.6 micromol / L to 176.8 micromol / L) Urate > 12 mg / dL (713.8 micromol / L) with serum creatinine > 2 mg / dL (176.8 micromol / L) Many causes of tubulointerstitial diseases may have these findings, lead nephropathy being the most common.