A nephrologist is a doctor who specializes in diagnosing and treating kidney diseases. These physicians handle everything from chronic kidney disease and kidney failure to high blood pressure caused by kidney problems, electrolyte imbalances, and kidney transplant care. If your primary care doctor suspects your kidneys aren’t working properly, a nephrologist is the specialist you’d be referred to.
What Nephrologists Do
Your kidneys filter your blood, remove waste, balance fluids, and help regulate blood pressure. When any part of that system breaks down, a nephrologist steps in. The specialty covers a wide range of problems: acute kidney injury (a sudden loss of kidney function), chronic kidney disease that worsens over time, inherited conditions like polycystic kidney disease, autoimmune diseases that attack the kidneys like lupus nephritis, and complications from diabetes that damage kidney tissue.
Nephrologists also manage conditions you might not immediately associate with kidneys. High blood pressure, for instance, is both a cause and a consequence of kidney disease. Uncontrolled blood pressure tightens the blood vessels your kidneys depend on, reducing blood and oxygen flow and accelerating damage. At the same time, failing kidneys make blood pressure harder to control. Up to 90% of people with chronic kidney disease also have hypertension, which is why nephrologists spend a significant portion of their practice managing blood pressure alongside kidney function.
Conditions a Nephrologist Treats
The list of kidney-related conditions is longer than most people expect:
- Chronic kidney disease (CKD), the gradual loss of kidney function over months or years
- Diabetic kidney disease, one of the most common causes of kidney failure
- Glomerular diseases, where the tiny filters inside the kidneys become inflamed or damaged
- Polycystic kidney disease, an inherited condition where fluid-filled cysts grow in the kidneys
- Kidney stones, though urologists handle surgical removal
- Nephrotic syndrome, where the kidneys leak large amounts of protein into the urine
- Acute kidney injury, a sudden episode of kidney failure often triggered by illness, dehydration, or medication
- Renal artery stenosis, a narrowing of the blood vessels supplying the kidneys
- Lupus nephritis and other autoimmune conditions affecting the kidneys
When kidney disease progresses to the point where the kidneys can no longer sustain life on their own, nephrologists manage dialysis and coordinate kidney transplants.
Key Procedures and Treatments
Nephrologists are medical doctors, not surgeons, so their approach centers on diagnosis, medication management, and overseeing treatments like dialysis. One common procedure they perform directly is a kidney biopsy. During this procedure, a thin needle is guided through the skin into the kidney using ultrasound or CT imaging, and a small tissue sample is removed. That sample goes to a lab, where it helps the nephrologist determine exactly what type of kidney disease is present and how far it has progressed. In rare cases where a patient has a bleeding disorder or only one kidney, the biopsy is done through a small surgical incision using a tiny camera instead.
For patients whose kidneys have failed or are close to failing, nephrologists prescribe and oversee dialysis. Hemodialysis filters blood through a machine, typically three times a week at a dialysis center. Peritoneal dialysis uses the lining of your abdomen as a natural filter and can often be done at home. Your nephrologist determines which type suits your health, lifestyle, and remaining kidney function.
The Transplant Nephrologist’s Role
Kidney transplants involve a surgical team, but nephrologists play a central role before and after the operation. Before transplant, they evaluate whether a patient is a good candidate and manage the waiting list, making sure patients stay healthy and qualified while they wait for a donor kidney. They also evaluate potential living donors.
After transplant, the nephrologist takes over long-term care. This includes managing medications that prevent the body from rejecting the new kidney and monitoring for any signs the transplanted organ isn’t functioning well. Transplant nephrologists complete an additional year of specialized training beyond the standard nephrology fellowship to handle these cases.
How Nephrologists Differ From Urologists
This is a common point of confusion. Both deal with the kidneys, but their approaches are fundamentally different. Nephrologists are internal medicine doctors who treat kidney disease with medications, dialysis, and ongoing medical management. Urologists are surgeons who focus on the structural and surgical problems of the entire urinary tract, including the kidneys, bladder, ureters, and urethra, plus the male reproductive system.
A practical example: if you have a large kidney stone that needs to be physically removed, you’d see a urologist. If you keep forming kidney stones because of an underlying metabolic problem, or if those stones have damaged your kidney function, you’d see a nephrologist. Many patients with complex kidney issues see both.
Training and Qualifications
Becoming a nephrologist requires extensive training. After four years of medical school, a physician completes three years of internal medicine residency. Then comes a nephrology fellowship, which lasts at least two years for clinical practice. Physicians pursuing research careers add one to two additional years, and those specializing in transplant nephrology add a third year focused on transplant care. Fellowship programs must be accredited, and practicing nephrologists hold board certification in the specialty.
All told, a nephrologist has a minimum of nine years of training after college before they begin independent practice, and often more.
Why You Might Be Referred to One
Most people don’t seek out a nephrologist on their own. Your primary care doctor or another specialist typically makes the referral when something in your bloodwork, urine tests, or blood pressure readings points to a kidney problem. Common triggers include protein showing up in your urine, a significant or steady decline in your kidney filtration rate (often flagged on routine blood tests), blood pressure that won’t respond to standard medications, or unexplained swelling in the legs and ankles.
If you have diabetes or longstanding high blood pressure, your primary care doctor may refer you earlier as a precaution, since both conditions are leading causes of kidney disease. A nephrology referral doesn’t necessarily mean your kidneys are failing. It often means your doctor wants a specialist’s input on slowing down damage before it becomes serious.