Filtered sodium excretion fraction

The filtered sodium excretion fraction, also called FENa, is a measure of the percentage of glomerular filtered sodium and urinary excreted sodium, that is, the percentage of sodium that is filtered by the glomerulus without being reabsorbed by the renal tubules. Calculation formula: sodium excretion fraction = [(urine sodium × blood creatinine) / (blood sodium × urinary creatinine)] × 100%; sodium excretion fraction is the most sensitive index for identifying prerenal acute renal failure and acute tubular necrosis, positive The rate is 98%. Prerenal acute renal failure due to the relatively increased reabsorption of sodium by the renal tubules, reduces urinary sodium excretion, and FENa is significantly reduced. Acute tubular necrosis, the renal tubular can not absorb Na, so the urine Na excretion increased significantly. The use of diuretics can increase the excretion of sodium in the urine, so the sodium excretion fraction should not be used as a basis for diagnosis at this time.