What daily urine volume classifies oliguria in adults?

Oliguria is defined as a significantly reduced urine output, which is typically less than 400 mL per day in adults. This classification is important because it can indicate potential underlying health issues such as dehydration, acute kidney injury, or other renal problems. Monitoring urine volume can help in assessing kidney function and the body’s fluid status.

Understanding the threshold of 400 mL is crucial in clinical settings, as it is a clear marker that prompts further investigation into the patient's health. In contrast, higher volumes do not indicate oliguria, as these levels reflect a normal or even increased urinary output, which would not raise immediate concerns regarding renal function. Therefore, recognizing that less than 400 mL qualifies as oliguria helps healthcare providers make informed decisions for patient care and management.