Chronic kidney disease (CKD) is common in the United States, affecting more than one in seven adults, and most people who have it do not know. The kidneys can lose a large share of their function before symptoms appear. The two simple tests that detect CKD early are often already on your lab report. Understanding them gives you the chance to protect your kidneys for decades.
What the kidneys do
Your kidneys filter waste and extra fluid from your blood, balance salts and minerals, help control blood pressure, keep bones healthy and signal the body to make red blood cells. When they are damaged, waste builds up and these functions gradually fail.
The two key tests
eGFR (estimated glomerular filtration rate) estimates how well your kidneys filter blood. It is calculated from a blood test for creatinine, along with your age and sex. A normal eGFR is generally 90 or above, though it naturally declines a little with age.
Urine albumin-to-creatinine ratio (UACR) checks for albumin, a protein that should not leak into urine in significant amounts. Albumin in the urine is often the earliest sign of kidney damage, especially in diabetes. A UACR below 30 mg/g is considered normal.
CKD is diagnosed when eGFR is below 60, or there are signs of kidney damage such as raised urine albumin, for three months or more.
Stages of CKD
| Stage | eGFR | Kidney function |
|---|---|---|
| 1 | 90 or above (with signs of damage) | Normal function but kidney damage present |
| 2 | 60–89 (with signs of damage) | Mildly reduced |
| 3a | 45–59 | Mild to moderately reduced |
| 3b | 30–44 | Moderately to severely reduced |
| 4 | 15–29 | Severely reduced |
| 5 | Below 15 | Kidney failure |
Doctors combine the eGFR stage with the urine albumin level to estimate your risk of progression and of heart disease.
Main causes
- Diabetes, the leading cause of kidney failure in the United States
- High blood pressure, the second leading cause
- Glomerulonephritis and other kidney inflammation
- Polycystic kidney disease and other inherited conditions
- Repeated kidney infections or blockages, such as kidney stones or an enlarged prostate
- Long-term use of certain medicines, including high doses of NSAID painkillers
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Who should be tested
Ask for an eGFR and urine albumin test at least once a year if you have diabetes, high blood pressure, heart disease, a family history of kidney failure, or obesity, or are over 60. People of Black, Hispanic, Native American and Asian heritage have higher rates of kidney failure.
Symptoms
Early CKD usually has no symptoms. As it advances, people may notice:
- Swelling in the ankles, feet or around the eyes
- Tiredness and weakness
- Foamy urine
- Needing to urinate more often at night
- Itchy skin, muscle cramps and poor appetite
- Nausea, trouble concentrating and shortness of breath in later stages
How to slow CKD
Treatment today can slow kidney decline significantly, especially when started early.
Control blood pressure
A target below about 130/80 mmHg is common for people with CKD. ACE inhibitors or ARBs (such as lisinopril or losartan) lower blood pressure and reduce protein in the urine, giving extra protection.
Control blood sugar
Good diabetes control reduces kidney damage.
Use newer kidney-protecting medicines
- SGLT2 inhibitors, such as dapagliflozin and empagliflozin, slow CKD progression and reduce the risk of kidney failure, heart failure and death in many people with CKD, with or without diabetes.
- Finerenone reduces kidney and heart events in people with CKD and type 2 diabetes.
- GLP-1 medicines such as semaglutide have been shown to slow kidney disease in people with type 2 diabetes.
Other steps
- Avoid NSAIDs such as ibuprofen and naproxen when possible. Ask your doctor or pharmacist which pain relievers are safest.
- Check medicine doses. Many drugs need dose adjustment with reduced kidney function.
- Cut back on salt to help control blood pressure and swelling.
- Stop smoking.
- Stay active and keep a healthy weight.
- Protein and diet: in more advanced CKD, a dietitian may recommend adjusting protein, potassium and phosphorus intake.
- Statins to reduce the high heart risk that comes with CKD.
Kidney failure
When kidney function falls below about 15 percent, treatment options include dialysis (hemodialysis or peritoneal dialysis), a kidney transplant, or conservative care focused on comfort and quality of life. Planning ahead with a nephrologist, ideally from stage 4, gives the best outcomes.
The bottom line
Chronic kidney disease is common and silent, but two simple tests, eGFR and urine albumin, can detect it early. If you have diabetes or high blood pressure, make sure both are checked every year. Blood pressure and blood sugar control, newer medicines such as SGLT2 inhibitors, and avoiding kidney-harming drugs can slow or even halt progression.
This article is for general information and does not replace medical advice.