| The Clinical Significance of the Fractional Excretion of Uric Acid and Urea in the Differentiation of Acute Kidney Injury |
| Jong Soon Jang, M.D., Hee-Sung Kim, M.D., Shin Young Lee, M.D., Seung Ho Lee, M.D., Seung Jung Kim, M.D., Soon Kil Kwon, M.D. and Hye-Young Kim, M.D. |
| Department of Internal Medicine, College of Medicine and Medical Research Institute Chungbuk National University, Cheongju, Korea |
| 임상연구 : 급성 신손상의 감별진단에 있어서 요산 및 요소 분획 배설율의 임상적 유용성 |
| 장종순, 김희성, 이신영, 이승호, 김승중, 권순길, 김혜영 |
| 충북대학교 의과대학 내과학교실, 의학연구소 |
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| Abstract |
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Purpose:Fractional excretion of sodium (FENa) has been used in the differentiation of acute kidney injury (AKI) into traditional categories of prerenal azotemia (PR) and acute tubular necrosis (ATN). However, many patients with PR have already received diuretics or saline at the time of diagnosis, which increase FENa. In contrast, the fractional excretion of uric acid (FEUA) and urea (FEUN) is less influenced by diuretics. We investigated the diagnostic significance of the FEUA and FEUN in differentiating between PR and ATN.
Methods:The FENa, FEUA, and FEUN were calculated in 40 patients with PR and 30 patients with ATN at day 0 (D0), day 1 (D1) and day 2 (D2), sequentially.
Results:FEUA (PR 13.9±8.7% vs. ATN 33.2±27.0%, p<0.05) and FEUN (PR 32.1±18.9% vs. ATN 50.6±41.3%, p<0.05) were lower in PR than in ATN patients. At the cut-off value of 1% FENa, sensitivity and specificity for the detection of PR was 51.4% and 96.4%, respectively. When FENa, FEUA and FEUN were combined, sensitivity and specificity was 84% and100%, respectively. In the PR with FENa less than 1%, FENa significantly increased after treatment (D0 0.4±0.1% vs. D1 1.2±0.3% vs. D2 1.5±0.4 %, p<0.05), but FEUA and FEUN did not changed after treatment.
Conclusion:FEUA and FEUN may be useful in differentiating between PR and ATN. The combination of FENa, FEUA and FEUN might increase diagnostic sensitivity and specificity in the differential diagnosis of AKI. |
| Key Words:
Acute kidney failure, Diagnosis, Urinalysis, Urea, Uric acid |
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