You know where your brain and your lungs are located and, chances are, you don't need anyone to tell you why you need them. But Tony Eglert, president of the National Kidney Foundation of the National Capital Area, says, "If you walked down the hall and asked the first five people you saw, 'Do you know where your kidneys are?' " or what they do, "you'd be surprised at the answers."

The kidneys -- fist-sized organs that remove waste and extra fluid from the body, stimulate bone to make red blood cells and help regulate blood pressure and strengthen bones -- are located near the middle of the back, below the rib cage.

Diseased kidneys can compromise many bodily systems and cause anemia, malnutrition, heart disease and ultimately death. Here are some questions about kidney health:

Who is most at risk for kidney disease?

People over 65, African Americans and members of other minority groups, people with high blood pressure, people with diabetes, those with a family history of kidney disease, smokers, people with autoimmune disorders.

What symptoms and warning signs warrant attention?

Swelling in the ankles, feet, face or other parts of the body; burning or unusual sensation during urination; fatigue. None of these symptoms is exclusively caused by kidney disease, but they all merit concern.

What tests might your doctor order to diagnose kidney disease?

* A urinalysis to look for protein in the urine. (A healthy kidney keeps large molecules, such as proteins, in the blood and filters out only waste. Protein in the urine is a marker for a diseased or damaged kidney.)

* A blood test for creatinine, a waste product filtered from the blood by the kidneys. Generally, creatinine levels above 1.5 milligrams per deciliter in men and 1.2 in women are considered abnormal.

* For those without hypertension or diabetes, imaging tests such as ultrasound or CT scan may be recommended.

* A kidney biopsy.

How can a person prevent or slow down kidney disease?

* Exercise.

* Eat wisely to reduce risk. That may mean low salt for someone with hypertension, low sugar for diabetics. If disease develops, diet needs to be modified to control protein, salt and some minerals. In the final stages, a patient may need to eat a high-fat, high-calorie diet to maintain a healthy weight.

* Don't smoke.

* Maintain blood pressure below 130/80. Taking ACE inhibitors to control high blood pressure has been shown to protect the kidneys.

* If you have diabetes, control your blood sugar.

-- Ranit Mishori