Kidneys are like pint-sized processing plants. About as big as your fist, these organs remove waste, filter blood, control red blood cell production and help regulate blood pressure. They return about 200 quarts of fluid to the bloodstream each day.
Humans are usually born with two kidneys. About one in 750 people are born with a single kidney. This is more common in males.
Other people may have just one kidney because the other was removed due to injury or illness. Or, some people donate one of their kidneys to help someone with kidney failure.
In all these situations, one kidney can usually do the job of two with proper medical care.
How is life different with one kidney?
A single normal kidney grows faster, and is heavier and larger than when there are two. It may function at a level about 40 percent more than a single, paired kidney.
Most people with a single normal kidney have normal life spans and no problems. Any decrease in kidney function is usually mild.
One study followed kidney donors over the course of 20 to 37 years. Most had normal function and most problems were the same for people of the same age with two kidneys.
People having just one kidney due to any cause may need more check-ups than those with two normal kidneys.
The aftermath of donating a kidney
Live-donor kidney transplants are preferred for several reasons:
- Potential donors can be tested for best matches.
- Transplants can be done at times best for donor and recipient.
- Kidney function usually begins right away and is easier to monitor.
- Kidneys transplanted from people who have died may not function right away. People who receive these kidneys may need to stay on dialysis until function starts.
Long-term risks to kidney donors are small. After kidney removal, donors may be sore for a few weeks. Soreness may be less if surgery is done through a small cut (laparoscopy).
Having a single kidney may put you at higher risk if you are injured or become sick. Also, because a single kidney is larger, it's at greater risk for damage during contact sports. If you have just one kidney, you may need to stop certain activities or use special protective equipment.
You may also need regular blood pressure checks and tests for protein in the urine and serum creatinine levels. The latter is checked by a simple blood test and can help show if the kidney is filtering well.
If one kidney was removed because of illness or injury, it is important to prevent damage to or illness in the remaining kidney. In many cases, though, the failure of one kidney does not mean a healthy kidney will fail.
Created on 07/21/2008
Updated on 11/18/2011
- National Kidney Foundation. How your kidneys work.
- Organ Procurement and Transplantation Network. National data.
- National Kidney Foundation. Living with one kidney.
- Ramcharan T, Matas A. Long-term (20-37 years) follow-up of living kidney donors. American Journal of Transplantation. 2002;2(10):959-964.