FENa Calculator


Please wait.. loading-icon
  • Table of Contents

Fractional Excretion of Sodium (FeNa) Calculator

The fractional excretion of Sodium (FENa) is most important tools mostly used in medical field like in nephrology or used bu health professional to identify nephrological issues. This Calculator can be used in Renal issues to identify exceretion od sodium relative to its filtration in the kidney. Understanding FeNa provides crucial insight into the pathophysiology of various renal issues, aiding in dignosis treatment and patient management.

What is Frational Excretion of Sodium (FENa).

FENa serve as a matric  to assess renal tubular function and distinguish between prerental, postrental etology intrinsic renal of acute injury (AKI).The percentage of sodium that is eliminate through urine.


 FeNa= (Urinesodiumconcentration×Plasmacreatinineconcentration)×100‚Äč /  (Plasmasodiumconcentration×Urinecreatinineconcentration)       

How FENa canbe helpful in Clinical Practice?

Diagnosis of AKI Types:

FeNa plays an important role to distinguish amoung the prerental AKI and intrinsic AKI (due to decreased renal perfusion) caused the kidney to retain sodium, that leads to decrease the FeNa (<1%). On the other hand intrinsic AKI (due to renal parenchymal) that impair Na reabsorption , resulting in evelated FeNa(>2%).

Assessment of Volume Status:

FeNa is very useful tool to differentiate between Hypovolemia and euvolemia. In the case of hypovolemia (e.g. dehydration) .the level of FeNa generally low. In the other side hypovolemia and euvolemia conditions (e.g. heart failuare, nephrotic syndrome often exhibit higher FeNa values).

Monitoring Response to Therapy

NaFe has capacity to monitor the effectiveness of intervantion in management of AKI.Changings in FeNa therapy like diuratics andfluid restruction gives us valueble imformation about renal responsiveness and guide further treatment decision.

Prognostic Indicator

Increase in FeNa associated with worst results in AKI such as an insrease in mortality rate and prolonged hospitals stay. Constantly monitoring in feNa level can assist in predicting patient prognosisn and directing guide clinical management stratigies.

Limitations and Considrations


FeNa interpretation may be affected by various factore such as diuratic use,  non-renal Na loses and changes in renal perfussion pressure. Clinicains should take these factors in considrations while anaylsis the FeNa results.


FeNa values can overlap different causes of AKI, its limitations in specifying in certain clinical scenarios, Therefore intreption of FeNa should be integrated with other clinical and labortary findings.

Clinical Context

FeNa  should be interpreted in conjustion in patient's clinical presentation, his medical history as well as his libortary parameters to improve diagnotic accuracy and giude appropriate management dicision.


The FeNa is very useful tool for physicians and healthcare professionals in evaluation of renal functions and diagnosing various kidney disorders.By evaluating the fractional excretion of sodium, clinical can differentiate between prerenaland intransic cause of AKI,as certain volume  status, monitor treatment response and prognosticate patient outcomes.While FeNa has limitations, incorporating it into clinical practice alongside comprehensive patient assessmant increase the dignotic accuracy and improve individual care in  nephrology and critical care setting.