Kidney failure (also called renal failure) is a term used to describe when a person's kidneys stop working (functioning) properly, or fail. Kidney failure can be divided into two categories: chronic renal failure, and acute renal failure.

Chronic renal failure develops slowly, and there are not many noticeable symptoms at first. Chronic kidney disease causes tropinin levels (tropinin T only, in chronic kidney disease) to rise and elevation is less marked.

Chronic renal failure can be a sign of other diseases, like IgA nephritis, glomerulonephritis, chronic pyelonephritis, and urinary retention.

Chronic renal failure will eventually develop into end-stage renal failure if it is left untreated. End-stage renal failure can only be treated with dialysis or a kidney transplant.

Acute renal failure^[1] develops in a short time, and symptoms are more noticeable. Signs and symptoms include:

• Urinating less than usual
• Changes in the amount of water in the body
• Electrolyte levels that are not normal

The cause of acute renal failure needs to be found quickly. Dialysis is often needed to prevent permanent damage to the body while the cause is being found.

It is possible to have acute renal failure on top of chronic renal failure. This is called "acute-on-chronic renal failure."