What is the daily urinary output have to be and for how long to be considered oliguria?

Oliguria is defined as a reduced urine output. Specifically, it is quantified as a daily urine output of less than 400 milliliters (mL) in adults.

Duration

For the output to be considered oliguria, this reduced urine output must occur over a span of 24 hours. If someone consistently produces less than 400 mL of urine per day for this duration, they would be classified as having oliguria.

In clinical settings, oliguria can be indicative of various health issues, including dehydration, kidney problems, or urinary obstructions, and it often requires further medical evaluation to determine the underlying cause.