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OnlineKidneyDr. Joan J. Morales Lappot, MD · Nephrology
Kidney Health 101

Two small organs doing a very big job.

Each day your kidneys filter about 150 quarts of blood, removing waste and extra water as 1–2 quarts of urine. They also help control blood pressure, make red blood cells and keep bones strong.

Kidney Ureter Bladder
Each kidney is about the size of a fist, just below the rib cage on either side of the spine.

What your kidneys do

01Filter wasteRemove toxins and extra fluid from your blood.
02Balance mineralsKeep sodium, potassium and phosphorus in a safe range.
03Control blood pressureAdjust fluid and hormones that set your pressure.
04Make red blood cellsRelease erythropoietin (EPO), which signals the bone marrow.
05Keep bones strongActivate vitamin D so your body can use calcium.

The stages of chronic kidney disease

Stages are based on your eGFR — an estimate of how much blood your kidneys filter each minute, calculated from a simple blood test. Normal is roughly 90 or above.

Stage 1eGFR 90+Normal filtering, with signs of damage
Stage 260–89Mild decrease
Stage 3a45–59Mild to moderate
Stage 3b30–44Moderate to severe
Stage 415–29Severe; plan for dialysis or transplant
Stage 5Under 15Kidney failure
Your doctor also checks a urine test for albumin (protein), which adds to the picture of kidney health at every stage.

Who is at higher risk?

  • Diabetes
  • High blood pressure
  • Heart disease
  • A family history of kidney failure
  • Hispanic, Black, American Indian or Asian American heritage
  • Age 60 or older

Symptoms come late

Early kidney disease usually has no symptoms — testing is the only way to know. Later signs can include:

  • Swelling in the feet, ankles or around the eyes
  • Foamy urine, or urinating more or less often
  • Tiredness, itching, poor appetite or nausea
If the kidneys fail

Knowing your options — honestly

Deciding when — or whether — to start dialysis is personal. It depends on your symptoms and quality of life, not lab numbers alone, and you'll always get a clear recommendation.

Independent advice. I have no conflicts of interest with large dialysis organizations, so the guidance you receive is about your health and your life.

Peritoneal dialysis

At home

Uses the natural lining of your belly as a filter, often overnight while you sleep.

Home hemodialysis

At home

A machine cleans your blood on a schedule that fits your day, after training with a care partner.

In-center hemodialysis

At a clinic

Usually three times a week for a few hours, with nurses and technicians doing the work.

Kidney transplant

From a living or deceased donor

For many people, the best long-term option. We can start the evaluation early.

Care without dialysis

Conservative care

Managing symptoms with medicines and diet. For some people, this is the right choice.

Video · 2 minutesAcute kidney injury: when the kidneys stop working suddenlyCauses, warning signs, and why early treatment matters. Watch on YouTube →

Six ways to protect your kidneys

Keep blood pressure at goal. Ask me what your personal target is.
Control blood sugar if you have diabetes.
Limit pain relievers like ibuprofen and naproxen; ask before taking them.
Eat less salt — see the kidney diet guide.
Stay active and don't smoke. Both protect your blood vessels.
Get tested yearly if you're at risk: a blood test and a urine test.