Dr. Thomas Nickolas, MD, MS, talks to us about what kidney failure is and how you can find out if you have it. Dr. Nickolas is a nephrologist (kidney disease doctor) at New York Presbyterian Hospital in Northern Manhattan. He sees a lot of patients who come in too late after their kidneys are already failing when there's not much that can be done. He encourages people to come in earlier so he can help people keep their kidneys from failing.

Q: What is kidney failure?

A: Kidney failure (also known as kidney disease) means that a person's kidneys are not working as well as they should be. When kidneys begin to fail, it means that they aren't filtering poisons from the body. This also means that the salt that we eat everyday isn't being cleared from the body by the kidneys.

Kidney failure is a silent process, which means you don't feel any different when your kidneys are failing than when they are working normally. It's not like how you'd feel chest pain when you have a heart attack - with kidney failure you don't feel anything at all. The only way to know that your kidneys are failing is if your doctor tests them with a blood or urine test.

Q: Where can you get a blood or urine test to see if you have kidney failure?

A: The routine is for your doctor to do a blood test and a urine test. If any blood or protein is in the urine that isn't normal he or she would then send you to see a nephrologist so you can figure out a plan to keep your kidneys as healthy as possible.

Q: Will you know when you have kidney failure if you don't get tested?

A: No. That's the problem. When you have a kidney attack, you don't feel a thing at all. The only thing you know is that one day you may find yourself just feeling really, really, really ill but without any real symptoms besides feeling too tired or not really feeling like eating or not really being able to think clearly. These are called "nonspecific symptoms," which means you can have these symptoms or signs of illness for many different illnesses. When you go to the hospital for these symptoms, the next thing you know you are told that your kidneys don't work anymore. At that point something needs to be done, and most likely you would have dialysis.

For this reason it's very important that you have a yearly check-up with your doctor and they check to make sure your kidneys are working well by checking your blood pressure, taking blood tests and testing your urine so they pick up any kidney problems early. The earlier you know that your kidneys are failing, the easier it is for a doctor to help you to make sure that things don't get any worse.

Q: Can your kidneys get better if you find out early that you have kidney disease?

A: Unfortunately, once your kidneys are damaged - they're damaged. Our goal is to keep you with what you have. We want to keep everybody off dialysis and we want to keep everyone without a transplant because your own kidneys are better than anything else. But in order to make sure your kidneys don't fail or that your kidney function doesn't get any worse we have to find your kidney failure early.

Read more from Dr. Nickolas by clicking the links below:

• Nephrologists
• Treatments for kidney failure
• Kidneys regulate blood pressure
• Low cholesterol to keep your kidneys healthy
• Who's most likely to get kidney disease

To listen to our interview with Dr. Nickolas, click here.