<prompt> Oliguria is defined as -24 hour urine output 200 ml24 hour urine output 300 ml24 hour urine output 400 ml24 hour urine output 500 ml  <response>: Ans. is c i.e., 24 hour urine output 400 ml Oliguria and Anuria Oliguria refers to a 24-h urine output 400 mL, and Anuria is the complete absence of urine formation 100 mL in 24 hours. 