On Monday’s morning report, we discussed the case of an elderly female presenting with hemoptysis and AKI. Part of our discussion focused on FeNa and FeUrea. These tests are commonly ordered reflexively during evaluation of AKI, but are they the best use of hospital resources. A 2016 article by Dr. Pahwa and Dr. Sperati attempted to address this question.
Key Points :
- The initial studies investigating FeNa and FeUrea focused on select populations with small sample sizes. These findings are likely not reflective of the general inpatient population.
- FeNa and FeUrea often had minimal impact on the pre-test probability.
- Rather than obtaining FeNa and FeUrea, the authors suggest focusing on management:
- Fluid administration vs diuresis in the setting of suspected pre-renal AKI.
- Fluid administration in the setting of suspected ATI if hypovolemia is present.
- Urine sediment can help differentiate between ATN and pre-renal AKI, in addition to evaluating for other etiologies of AKI (glomerulonephritis and acute interstitial nephritis) .
- FeNa can be helpful in the diagnosis of hepatorenal syndrome.
Link to article: https://www.journalofhospitalmedicine.com/jhospmed/article/127988/urinary-excretion-indices-aki
Additional review article: https://cjasn.asnjournals.org/content/7/1/167