A nephrologist is a type of doctor who focuses on the diagnosis and treatment of kidney conditions. Nephrologists also receive training to help manage the impact of kidney dysfunction on the rest of the body.
A doctor may refer someone to a nephrologist if they believe that the person shows signs of kidney problems, such as kidney disease, infections, or growths.
In this article, we discuss what nephrologists do, the types of conditions they treat, the procedures they perform, and when someone might need to visit one.
What is a nephrologist?
A nephrologist is a kidney specialist. They can perform diagnostic tests and treat conditions related to the kidneys.
Nephrology is a subspecialty of internal medicine. To become a nephrologist, a person should:
- complete an undergraduate and medical degree
- complete a 3 year residency in basic internal medicine training
- complete a 2 or 3 year fellowship focusing on nephrology
- pass a board certification exam (optional)
Nephrologists often work in individual or group practices caring for people referred from family doctors or specialists. Many nephrologists also consult on cases in hospitals and oversee dialysis units, usually in a clinic or a hospital.
Some nephrologists also focus on clinical research, while others work as professors and supervisors.
Which medical conditions do they treat?
Nephrologists treat conditions that involve or impact the kidneys, both directly and indirectly.
Some common conditions a nephrologist treats or helps treat include:
- advanced or chronic kidney disease
- glomerular conditions, such as glomerulonephritis and nephrotic syndrome
- tubulointerstitial kidney diseases
- tubular defects
- kidney vascular conditions, such as renal artery stenosis
- kidney infections
- kidney neoplasms, or abnormal growths
- structural or functional abnormalities of the kidney, bladder, or urine collection system, such as nephrolithiasis
- high blood pressure
- autoimmune conditions involving the kidneys
- electrolyte, fluid, and acid-base imbalances or disturbances
- some metabolic disorders, such as diabetes
What procedures do they perform?
Their training in internal medicine and nephrology allows nephrologists to perform a very long list of tests, procedures, and treatments.
However, the most common tests they use to diagnose or monitor kidney conditions are blood and urine tests.
The kidneys filter excess fluid and waste from the blood, creating urine. This means that blood and urine tests can often reveal whether or not the kidneys are working properly.
Urine tests can also check for abnormal levels of proteins linked to kidney damage in the urine.
The following sections discuss these types of test in more detail.
Common blood tests include:
The body produces creatinine as a byproduct of day-to-day muscle damage.
However, having high levels of creatinine in the blood, or elevated serum creatinine, is usually a sign of progressive kidney disease.
Serum creatinine levels depend on factors including age, body size, and race. A value of greater than 1.2 for women or greater than 1.4 for men may signal kidney problems.
Glomerular filtration rate
The glomerular filtration rate (GFR) tests how well the kidneys are able to filter out excess fluid and waste from the blood. Nephrologists can determine this value by calculating the serum creatinine level and factoring in age, sex, and race.
Value typically decreases with age, but important GFR values include:
- 90 or above (normal)
- 60 or below (kidney dysfunction)
- 15 or below (high risk of needing dialysis or a transplant for kidney failure)
Blood urea nitrogen
Urea nitrogen is a waste product from the body breaking down protein in foods and drinks. Typically, blood urea nitrogen (BUN) levels increase with decreasing kidney function.