Overview of ARF

Acute renal failure (ARF) is the rapid breakdown of renal (kidney) function that occurs when high levels of uremic toxins (waste products of the body's metabolism) accumulate in the blood. ARF occurs when the kidneys are unable to excrete (discharge) the daily load of toxins in the urine.

Based on the amount of urine that is excreted over a 24-hour period, patients with ARF are separated into two groups:

  • Oliguric: patients who excrete less than 500 milliliters per day (< 16 oz/day)
  • Nonoliguric: patients who excrete more than 500 milliliters per day (> 16 oz/day)

In nonoliguric patients, the urine is of poor quality (i.e., contains little waste) because the blood is not well filtered, despite the fact that an adequate volume of urine is excreted.

Both kidneys are failing when ARF occurs. One normally functioning kidney can maintain adequate blood filtering.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 29 Apr 2001

Last Modified: 27 Aug 2015