Nephrology
Nephrology is the medical specialty focused on the kidneys, including blood filtration, fluid balance, electrolytes, blood pressure, kidney disease, dialysis, transplant care, and prevention.
What nephrology is
Nephrology is the branch of medicine that focuses on the kidneys and the body systems they help regulate. Nephrologists diagnose and manage kidney disease, abnormal urine findings, fluid overload, electrolyte and acid-base problems, difficult blood pressure, kidney stones in some contexts, dialysis, and care before and after kidney transplant. The field sits close to cardiology, endocrinology, critical care, urology, nutrition, and public health.
What kidneys do
Kidneys filter blood, remove waste products, balance water and salts, help control blood pressure, maintain acid-base balance, activate vitamin D, and make hormones involved in red blood cell production. Each kidney contains many filtering units called nephrons. Blood enters a nephron, fluid is filtered, useful substances are reclaimed, and extra waste and water leave the body as urine.
Symptoms and first clues
Kidney problems can be quiet for a long time. Some people first notice swelling, fatigue, foamy urine, blood in urine, changes in urination, itching, nausea, muscle cramps, high blood pressure, or shortness of breath from fluid overload. Others are found through routine blood or urine tests. Nephrology pays close attention to trends, because a small change over time can matter more than a single number.
Tests and interpretation
Creatinine and estimated glomerular filtration rate, or eGFR, give a rough picture of kidney filtering. Urine albumin can reveal kidney damage even when eGFR is still preserved. Electrolytes, bicarbonate, calcium, phosphorus, blood counts, immune tests, ultrasound, CT, and medication review can help identify causes and complications. A kidney biopsy may be used when tissue diagnosis will change treatment.
Conditions nephrologists treat
Nephrology covers acute kidney injury, chronic kidney disease, glomerulonephritis, diabetic kidney disease, hypertensive kidney disease, inherited kidney disorders, polycystic kidney disease, kidney involvement from lupus or vasculitis, electrolyte disorders, acid-base disorders, nephrotic syndrome, kidney failure, and complications of dialysis or transplant care. Many conditions are managed with long follow-up rather than a single visit.
Dialysis and transplant care
When kidneys can no longer do enough work to keep the body stable, kidney replacement therapy may be needed. Hemodialysis filters blood through a machine, while peritoneal dialysis uses the lining of the abdomen as a filter. Kidney transplant can provide another treatment path for some people. Nephrology helps plan timing, access, medicines, complications, and shared decisions about goals of care.
Prevention and daily management
Prevention focuses on protecting remaining kidney function and reducing cardiovascular risk. Depending on the person, this may include blood pressure control, diabetes management, avoiding kidney-toxic medicines when possible, treating albumin in urine, adjusting drug doses, limiting salt, planning safe imaging contrast use, vaccination, smoking cessation, and nutrition advice. Care plans must be individualized because too much fluid, too little salt, or the wrong diet can be harmful in some kidney conditions.
Why it matters
Kidneys influence nearly every organ through fluid, electrolytes, hormones, blood pressure, and waste removal. Kidney disease can raise the risk of heart disease, anemia, bone disease, medication toxicity, hospitalization, and kidney failure. Good nephrology care can slow progression, catch complications earlier, prepare people for dialysis or transplant when needed, and keep treatment aligned with daily life.