尿鈉與體液容積

FeNa<1-2% or UNa<10-30 mEq/L 代表有效血液容量下降, 除非:
1. Low salt diet (salt intake <1 g/day)
2. aGN (eGFR下降)
3. AIN (eGFR下降)
4. Sepsis (eGFR下降)
5. Acute urinary tract obstruction
6. Some AKI (e.g. myoglobinuria, hemoglobinuria, contrast nephropathy, acute transplant rejection)

7. Renal artery stenosis

8. Vasoconstriction: CNI, contrast media