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TABLE 52-2 Laboratory Findings in Acute Renal Failure |
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|
Index |
Prerenal Azotemia |
Acute Tubular Necrosis |
|
BUN/PCr ratio |
>20:1 |
10–15:1 |
|
Urine sodium UNa, meq/L |
<20 |
>40 |
|
Urine osmolality, mosmol/L H2O |
>500 |
<350 |
|
Fractional excretion of sodium |
<1% |
>2% |
|
Urine/plasma creatinine UCr/PCr |
>40 |
<20 |
|
Urinalysis (casts) |
None or hyaline/granular |
Muddy brown |