1. Persistent fatigue and weakness

What you may notice: You feel exhausted even after a full night’s sleep, have less energy for daily activities, or tire easily when walking or climbing stairs.

Why it may happen: Damaged kidneys can contribute to anemia, a condition in which your body has too few healthy red blood cells to carry oxygen efficiently. Waste buildup and other complications can also cause fatigue.

What to do: If fatigue persists without a clear explanation, ask a healthcare professional about a blood count and kidney function tests. Fatigue alone does not prove kidney disease.

2. Swelling in the feet, ankles, or legs

What you may notice: Your shoes feel tight, your ankles appear puffy, or your lower legs swell, especially after sitting or standing.

Why it may happen: The kidneys may retain excess sodium and water. Some kidney conditions also cause protein to leak into urine, allowing fluid to accumulate in body tissues.

What to do: Arrange a medical assessment if swelling is new or persistent. Seek emergency care if it occurs with severe breathlessness or chest pain.

3. Puffiness around the eyes

What you may notice: Your eyelids or the area around your eyes looks swollen, particularly in the morning.

Why it may happen: Some kidney diseases allow albumin, an important blood protein, to escape into the urine. Lower blood protein levels can contribute to fluid collecting around the eyes.

What to do: Persistent puffiness, especially when combined with foamy urine or swollen ankles, warrants a urine protein test. Allergies, poor sleep, and other conditions can also cause puffy eyes.

4. Foamy or unusually bubbly urine

What you may notice: Your urine repeatedly develops thick foam or bubbles that do not disappear quickly.

Why it may happen: Protein in the urine, called proteinuria or albuminuria, can cause persistent foaming and may indicate damage to the kidney’s filtering units.

What to do: If this happens regularly, ask for a urine albumin-to-creatinine ratio (uACR) test. A forceful urine stream or concentrated urine can also produce bubbles, so appearance alone cannot confirm kidney damage.

5. Blood in the urine

What you may notice: Urine appears pink, red, tea-colored, or cola-colored. Sometimes blood is present in amounts too small to see.

Why it may happen: Kidney filter inflammation, kidney stones, urinary tract infections, and other urinary tract conditions can cause bleeding.

What to do: Visible blood in the urine should be evaluated promptly, even if it happens only once or causes no pain. Do not assume it is kidney disease; other causes need to be ruled out.

6. Urinating more frequently, especially at night

What you may notice: You wake up several times during the night to urinate or need to use the bathroom much more often than usual.

Why it may happen: Kidney disease can impair the kidneys’ ability to concentrate urine. However, diabetes, urinary infections, prostate enlargement, some medicines, and excess evening fluids are other possible causes.

What to do: If the change persists, discuss it with your clinician. Do not drastically reduce your water intake simply to avoid nighttime bathroom visits.

7. Pain in the side or back

What you may notice: Pain in one or both sides of your back, beneath the ribs, sometimes spreading toward the lower abdomen or groin.

Why it may happen: Kidney stones, kidney infections, or obstruction of urine flow can cause pain. Chronic kidney disease, however, often causes no kidney-area pain.

What to do: Seek urgent medical care if you have side or back pain with fever, chills, vomiting, or painful urination. Sudden severe pain or inability to urinate also requires urgent assessment.

8. Nausea, vomiting, or loss of appetite

What you may notice: Food becomes unappealing, you feel sick after eating, or you experience repeated nausea or vomiting.

Why it may happen: In advanced kidney disease, waste products and changes in the body’s chemical balance can affect appetite and digestion. Many other illnesses can produce the same symptoms.

What to do: Arrange medical evaluation for persistent symptoms. Repeated vomiting, inability to keep fluids down, or markedly reduced urination needs urgent assessment because dehydration can also injure the kidneys.

9. Persistent dry or itchy skin

What you may notice: Your skin feels unusually dry, itches without an obvious rash, or itching interferes with sleep.

Why it may happen: Advanced kidney disease can disrupt mineral balance and contribute to itching. Dry skin, eczema, allergies, and medication reactions are also common explanations.

What to do: Seek assessment if itching is persistent or widespread, particularly if accompanied by fatigue, swelling, or changes in urination. Moisturizers may help dryness but will not treat an underlying kidney problem.

10. Trouble sleeping

What you may notice: Difficulty falling asleep, frequent waking, restless legs, or feeling unrefreshed in the morning.

Why it may happen: Advanced kidney disease may contribute to itching, restless legs, nighttime urination, or sleep-related breathing problems.

What to do: Persistent sleep difficulties deserve evaluation, but insomnia alone is not a reliable indicator of kidney disease. Mention any accompanying urinary symptoms or swelling to your clinician.

11. Difficulty concentrating or mental fog

What you may notice: You struggle to focus, forget things more often, or find routine mental tasks unusually difficult.

Why it may happen: Advanced kidney disease can cause anemia and changes in waste products or electrolytes that affect brain function. Sleep deprivation, stress, and many other conditions can do this too.

What to do: Arrange an assessment if the problem persists. Sudden confusion, unusual drowsiness, or difficulty waking someone is an emergency, especially if accompanied by other signs of serious illness.

12. High blood pressure

What you may notice: Repeated blood pressure readings are above your recommended range. Often, you will feel completely normal.

Why it may happen: Diseased kidneys may retain salt and water and disrupt hormone systems that regulate blood pressure. High blood pressure can also damage kidney blood vessels, creating a cycle of worsening kidney health.

What to do: Monitor your blood pressure and discuss persistently elevated readings with your healthcare professional. Blood pressure is a risk factor and possible consequence of kidney disease, not proof of it.

13. Unexplained weight changes

What you may notice: Your weight increases quickly over a few days, or you lose weight without trying.

Why it may happen: Rapid weight gain can reflect fluid retention. Unintentional weight loss may occur with advanced disease due to poor appetite, nausea, or other complications.

What to do: Track changes alongside swelling and other symptoms. Rapid weight gain with worsening swelling or breathing difficulty needs prompt medical attention. Weight changes also have many non-kidney causes.

14. Frequent muscle cramps or spasms

What you may notice: Painful cramps in your calves, feet, or other muscles, especially at night.

Why it may happen: Kidney disease can disturb the balance of electrolytes and minerals, including calcium and phosphorus. Dehydration, exercise, and some medications can also cause cramps.

What to do: Discuss recurrent or severe cramps with your clinician. Do not start potassium, magnesium, or other mineral supplements without advice, because some can be dangerous when kidney function is reduced.

15. Dizziness or unusual weakness

What you may notice: You feel lightheaded when standing, weak during normal activities, or less able to exercise.

Why it may happen: Kidney-related anemia can cause weakness and dizziness. Dehydration, low blood pressure, medication effects, and other conditions may also be responsible.

What to do: Seek medical assessment if symptoms persist or recur. Fainting, severe weakness, chest pain, or shortness of breath requires urgent evaluation.

16. Shortness of breath

What you may notice: You become breathless with little activity, struggle to lie flat, or wake up gasping for air.

Why it may happen: Advanced kidney disease can cause fluid to accumulate in the lungs or contribute to anemia. Heart and lung conditions are other important possibilities.

What to do: Severe or sudden breathlessness, particularly at rest, is a medical emergency. Call emergency services rather than waiting for a routine kidney appointment.

17. Abnormal kidney blood or urine test results

What you may notice: A blood test shows elevated creatinine or a reduced estimated glomerular filtration rate (eGFR), or a urine test detects albumin.

Why it matters: These are measurable clues that can reveal kidney problems before physical symptoms appear.

What to do: Review abnormal results with a healthcare professional. A single abnormal test does not always establish chronic kidney disease; repeat testing, the degree of abnormality, and the overall clinical picture matter.

Unlike many other warning signs, these tests can detect disease even when you feel well.

1. Blood test: creatinine and eGFR

Creatinine is a waste product measured in the blood. The eGFR estimates how effectively your kidneys filter blood.

• An eGFR of 60 or higher may be compatible with healthy kidney function, depending on other findings.

• An eGFR below 60 may indicate reduced kidney function.

• An eGFR below 15 indicates severely reduced kidney function and may represent kidney failure.

A single result must be interpreted in context. Chronic kidney disease is generally defined by abnormalities persisting for at least three months.

2. Urine test: albumin-to-creatinine ratio (uACR)

This test detects albumin, a protein that can leak into urine when kidney filters are damaged.

• A uACR of 30 mg/g or less is generally considered normal.

• A uACR above 30 mg/g may indicate kidney damage and usually needs further assessment.

Temporary changes can occur after strenuous exercise, illness, or other circumstances, so abnormal results may need repeating.

Control blood pressure and blood sugar. Follow your treatment plan and monitor your readings as recommended.

Reduce excess salt. Limit heavily salted packaged foods, processed meats, and frequent fast-food meals.

Drink fluids appropriately. Avoid dehydration, but do not force excessive amounts of water. People with advanced kidney disease or heart failure may need individualized fluid limits.

Be careful with pain medicines. Frequent or high-dose use of NSAIDs such as ibuprofen and naproxen can injure the kidneys, particularly during dehydration or in people with existing kidney disease. Ask your clinician or pharmacist what is safe for you.

Avoid unverified kidney cleanses and supplements. No detox drink or home remedy can replace kidney function testing and appropriate medical treatment.

Stay active and avoid smoking. Regular physical activity, a balanced diet, and avoiding tobacco support overall cardiovascular and kidney health.