Oliguria By Cherisse Berry, MD, New York University School of Medicine Reviewed / Revised Dec 2022 View Patient Education Etiology Evaluation Treatment Key Points Topic Resources Fractional Excretion of Sodium Some Causes of Oliguria Oliguria is urine output < 500 mL in 24 hours in an adult or < 0.5 mL / kg / hour in an adult or child (< 1 mL / kg / hour in neonates).