Overview of CRF

Chronic renal failure (CRF) or kidney failure is the progressive loss of kidney function. The kidneys attempt to compensate for renal damage by hyperfiltration (excessive straining of the blood) within the remaining functional nephrons (filtering units that consist of a glomerulus and corresponding tubule). Over time, hyperfiltration causes further loss of function.

Chronic loss of function causes generalized wasting (shrinking in size) and progressive scarring within all parts of the kidneys. In time, overall scarring obscures the site of the initial damage. Yet, it is not until over 70 percent of the normal combined function of both kidneys is lost that most patients begin to experience symptoms of kidney failure.

Types of Chronic Renal Failure

Chronic renal failure (CRF), kidney failure, can be classified by the site (location) of primary damage:

  • Pre-renal CRF
  • Post-renal CRF (obstructive uropathy)
  • Renal CRF

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

Published: 30 Apr 2001

Last Modified: 04 Sep 2015