Differences between functional and parenchymal ARF INDEXES F- ARF P- ARF Urine specific gravity 020 Urine osmolality 500 mmol /L 350 mmol /L Urine na <20 mmol /L 40 mmol /L Urine Cr/ Plasma Cr >40 20 Renal failure index (RFD FENa 2 Urinary sediment Normal Proteins. cells. casts urine na urine nat/serum Na RF= urine Cr/plasma Cr FENa urine Cr/plasma Cr36 urine Na+ urine Na+ /serum Na+ urine Cr/plasma Cr; urine Cr/plasma Cr Differences between functional and parenchymal ARF RFI = FENa = INDEXES F - ARF P - ARF Urine specific gravity > l .020 < l .0l 5 Urine osmolality > 500 mmol / L < 350 mmol / L Urine Na+ < 20 mmol / L > 40 mmol / L Urine Cr / Plasma Cr > 40 < 20 Renal failure index (RFI) < l > 2 FENa < l >2 Urinary sediment Normal Proteins, cells, casts