Final answer:
Oliguria is an abnormally low urine output, usually less than 600 ml/day, that can signal a risk of nephrotoxicity and is indicative of potential kidney dysfunction, not optimal kidney function.
Step-by-step explanation:
Oliguria refers to an abnormally small production of urine, typically defined as less than 600 ml/day. It is a concerning symptom that suggests a reduced kidney function and can be caused by conditions like fever, shock, vomiting, and diarrhea. Oliguria indicates that the kidneys are not performing optimally and may suggest a risk of nephrotoxicity, or damage to the kidneys due to toxic substances. Conditions such as acute renal failure and nephritis can also cause an even more severe reduction in urine output known as anuria, where the excretion can be less than 10 ml/day or stop entirely. It is crucial to differentiate between normal urinary output, urinary tract infection (UTI), and oliguria in clinical settings to provide appropriate care.