What Is a Nephrologist?

A nephrologist is a medical doctor who specializes in kidney care and treating diseases of the kidneys. The term nephrologist comes from the Greek word “nephros”, which means kidney or renal and “ologist” refers to someone who studies. Nephrologists are also called kidney doctors. Nephrologists are educated in internal medicine and then undergo more training to specialize in treating patients with kidney diseases. They commonly treat chronic kidney disease (CKD), polycystic kidney disease (PKD), acute renal failure, kidney stones and high blood pressure and are educated on all aspects of kidney transplantation and dialysis.

Becoming a nephrologist

Nephrology is categorized as a specialty of internal medicine. Nephrologists must graduate from an approved medical school, complete a three-year residency in internal medicine and pass the American Board of Internal Medicine (ABIM) certification exam before they can begin to study nephrology.

Once they have passed the ABIM exam and been accepted into a nephrology program, they must complete a two- to three-year fellowship in nephrology. This fellowship must be accredited by the Accreditation Council for Graduate Medical Education (ACGME).

During this fellowship, aspiring nephrologists learn about:  

  • Glomerular/vascular disorders — Glomerular/vascular disorders are disorders of the glomeruli or clusters of blood vessels in the kidneys. Kidney doctors learn treatment methods to help slow the progression of these disorders to preserve kidney function for as long as they can.
  • Tubular/interstitial disorders — Tubular/interstitial disorders affect the tubules of the kidneys and the surrounding tissues. The tubules collect the filtered fluid from the kidneys that ultimately becomes urine. Kidney doctors learn the symptoms of these disorders and how to treat them.
  • Hypertension — Hypertension is another word for high blood pressure, and it is the second leading cause of end stage renal disease (ESRD) in the U.S. When kidneys excrete too much of a substance called renin, blood pressure may increase. Kidney doctors learn about the different kinds of medicines that can lower blood pressure, as well as other methods for lowering blood pressure such as diet and exercise.
  • Dialysis — Dialysis is the process of cleaning the blood when the kidneys no longer function. Kidney doctors learn about hemodialysis and peritoneal dialysis — the two types of dialysis — so they can match their patients with the dialysis treatment that works best for their health and lifestyle.
  • Kidney transplantation —  A kidney transplant takes place when someone receives a kidney from someone else to replace their own damaged kidneys. Nephrologists learn about all aspects of kidney transplantation so they can help their patients understand and prepare for this procedure.
  • Mineral metabolism — Mineral metabolism disorders occur when there are abnormal amounts of minerals in the blood. Kidney doctors learn how to correct or manage mineral metabolism disorders to make sure their patients get the amount of minerals they need for healthy growth and to keep their bodies functioning as they should.
  • Management of acute kidney failure — Acute kidney failure occurs when the kidneys suddenly stop working. Sometimes the kidneys can recover from acute kidney failure. Kidney doctors learn to treat all reversible situations that cause acute kidney failure, such as kidney stones, infections or major blood loss.
  • Management of chronic kidney disease — Chronic kidney disease (CKD) occurs when the kidneys slowly stop working over a period of time. There are five stages to CKD, with the last stage being end stage renal disease (ESRD). Kidney doctors learn about the five stages of chronic kidney disease and how to manage them so they can slow the progression of kidney disease and keep their patients as healthy as possible.
  • Nutrition — Nutrition plays a big part in slowing the progression of kidney disease and living well with kidney failure. Kidney doctors learn what nutrients kidney patients can and cannot have so they can help their patients get the nutrition they need.
  • Interpretation of x-rays, sonograms and other tests — Some kidney diseases are discovered through x-rays, sonograms and other tests. Kidney doctors learn how to interpret the results of these tests so they can make accurate diagnoses.

In addition, most nephrology fellowships require one to two years of clinical or laboratory research, during which time each physician becomes a true expert in more specialized areas of study.

During fellowship, nephrologists-in-training learn to diagnose and manage kidney diseases. They must be familiar with all surgical procedures associated with dialysis such as vascular access and catheter placement. They become experts on all forms of dialysis treatment such as hemodialysis and peritoneal dialysis and learn to perform kidney biopsies, tests during which small pieces of tissue are collected from the kidney for examination under a microscope. Once this is done, they are eligible to take the ABIM nephrology exam.

To specialize in pediatric nephrology (caring for children), students must take additional courses and pass another exam.

What does a nephrologist do?

A nephrologist generally sees patients who are referred by their primary care physicians or general physicians for problems related to the kidneys, high blood pressure or certain types of metabolic disorders. If someone feels they are having problems with their kidneys, they can seek out the care of a nephrologist. When a kidney doctor first meets with a patient, he or she will usually go over the patient’s medical history and do a complete physical.

A nephrologist will then do blood and urine tests to determine how well the patient’s kidneys are functioning. He or she may also order a kidney ultrasound. When necessary, a nephrologist may perform a kidney biopsy in order to better determine what is wrong with the kidneys. However, a nephrologist is not a surgeon and typically does not perform operations. Treatment of kidney cancer, prostate operations and removal of kidney stones are usually handled by a different type of physician known as a urologist.

If a nephrologist finds that a patient’s kidneys are not functioning as they should, he or she will help diagnose the cause and prescribe a treatment plan. If a kidney doctor detects kidney disease, he or she will do tests to determine what stage of kidney disease the patient is in and plan the patient’s treatment. The nephrologist will usually refer the patient to a renal dietitian, renal social worker and renal nurse who will help with the patient’s care. If the patient needs dialysis or a kidney transplant, his or her kidney doctor will discuss the different types of dialysis or refer the patient to a transplant center.

Nephrologists generally meet with dialysis patients several times per month and other types of kidney patients every one to three months. When a patient comes in for a check-up, the kidney doctor will evaluate the patient’s medical condition, address any new problems, check test results, make changes to the patient’s dialysis prescription if needed and refill or prescribe medications. During these visits, the nephrologist is also likely to adjust blood pressure medicines and may initiate or adjust therapy for a variety of other problems, such as diabetes, anemia and high cholesterol.

Every nephrologist has received extensive training in general internal medicine, and many nephrologists will treat their patients for other things besides kidney problems. It’s important that patients tell their kidney doctors if they notice any changes in their health.

Also, depending on the dialysis center, a nephrologist may have a managerial role in how the center runs. If this is the case, he or she will set up the policies and procedures for how the center should run, how dialysis treatments should be done and what roles the employees at the center will play in the process.

Who should see a nephrologist?

A person may be referred to a kidney doctor if he or she is experiencing:

  • Acute renal failure
  • Stage 4 or 5 chronic kidney disease
  • Accelerated decline in kidney function
  • Chronic urinary tract infections
  • Repeat urinary tract infections
  • High blood pressure that does not respond to medication
  • A glomerular filtration rate (GFR) of 30 or lower
  • Repeat kidney stones
  • Blood loss in the urine
  • Protein loss in the urine


Nephrologists, also referred to as kidney doctors, specialize in kidney care and commonly treat chronic kidney disease (CKD) and manage dialysis care for people with end stage renal disease. People with kidney problems may be referred to a nephrologist by their primary care physician or they may choose to go to a kidney doctor if they believe they have issues with their kidneys.