II. Indications

III. Precautions

  1. Results altered by Hyperkalemia Management
  2. Obtain lab sample prior to intervention if possible
    1. Do not delay treatment in emergent Hyperkalemia

V. Formula

  1. FEK = (Potassium Excretion x 100)/(total filtered load)
    1. Potassium (K+) Excretion = (Urine K++) / (Serum K++)
    2. Total Load = (Urine Creatinine) / (Serum Creatinine)
  2. FEK = (uK x sCr x 100) / (sK x uCr)

VI. Interpretation of Fractional Excretion of Potassium

  1. FEK <10%: Renal cause of Hyperkalemia
  2. FEK >10%: Extrarenal cause of Hyperkalemia
    1. May also be increased in Chronic Renal Failure

Images: Related links to external sites (from Bing)

Related Studies (from Trip Database) Open in New Window

Ontology: Measurement of fractional excretion of potassium (C1384695)

Concepts Diagnostic Procedure (T060)
SnomedCT 409082001
English Measurement of fractional excretion of potassium (procedure), Measurement of fractional excretion of potassium
Spanish determinación de la excreción fraccional de potasio (procedimiento), determinación de la excreción fraccional de potasio