kidney blood test explained
Informed by recognized medical guidance
Overview
A kidney blood test is a simple blood test that checks how well your kidneys are working. The kidneys filter waste from your blood, so the test measures levels of waste products like creatinine and urea. High levels can mean the kidneys are not filtering properly.
Key facts
- Creatinine is a waste product from muscle activity, and high levels may indicate kidney problems.
- The test is often done as part of a routine health check or if you have symptoms like swelling or fatigue.
- Your doctor may also check your eGFR (estimated glomerular filtration rate), which gives a more complete picture of kidney function.
Yes, kidney blood tests are very common. They are a standard part of many health checks, especially for people with high blood pressure, diabetes, or a family history of kidney disease.
Anyone can have a kidney blood test. It is most often done for adults, but children may have it if there are concerns about kidney function.
Symptoms
- Sudden inability to urinate
- Severe shortness of breath
- Chest pain or pressure
- ⚠Persistent swelling that doesn't improve
- ⚠Blood in urine
- ⚠Very high blood pressure
Common symptoms
- Fatigue and weakness
- Swelling in ankles, feet, or hands
- Changes in urination (more or less often, foamy or bloody urine)
Symptoms in children
- Poor growth or weight gain
- Frequent urination or bedwetting
- Swelling around the eyes
Symptoms in older adults
- Confusion or trouble concentrating
- Loss of appetite or nausea
- Muscle cramps or twitching
Causes
Main causes
- High blood pressure
- Diabetes
- Glomerulonephritis (inflammation of kidney filters)
Risk factors
- Family history of kidney disease
- Being over 60 years old
- Long-term use of certain painkillers (like NSAIDs)
When to see a doctor
See a doctor urgently if:
- If you have swelling that comes on quickly or difficulty breathing
- If you see blood in your urine
- If you have a very high blood pressure reading
Book a routine appointment if:
- If you have diabetes or high blood pressure, get checked regularly
- If you have symptoms like fatigue or changes in urination that last more than a few days
- Talk to your GP if you have a family history of kidney disease
Diagnosis
A kidney blood test is a simple blood draw from your arm. The sample is sent to a lab to measure creatinine, urea, and often eGFR. Your doctor will review the results with you.
Tests that may be done
- Blood test (creatinine, urea, eGFR)
- Urine test (to check for protein or blood)
- Imaging tests like ultrasound if needed
What to expect at your appointment
The blood test takes just a few minutes. You may feel a tiny prick. Results usually come back in a day or two. Your doctor will explain what the numbers mean.
Treatment
Treatment depends on the cause and stage of kidney disease. The goal is to slow the damage and manage symptoms. This may include controlling blood pressure, managing diabetes, and following a kidney-friendly diet.
Self-care at home
- Stay hydrated with water (unless your doctor says otherwise)
- Eat a balanced diet low in salt and processed foods
- Avoid smoking and limit alcohol
- Take medications as prescribed by your doctor
Medical treatments
Your doctor may prescribe medications to control blood pressure, lower cholesterol, or manage diabetes. In later stages, treatments like dialysis (where a machine filters your blood) or kidney transplant may be needed. Always talk to your doctor about your specific treatment plan.
When is surgery considered?
Surgery may be needed for a kidney transplant if kidney failure occurs. Your healthcare team will discuss options.
Living with this condition
Living with kidney disease often means regular check-ups, taking medications, and following dietary guidelines. You may need to monitor your blood pressure and urine at home.
Lifestyle tips
- Work with a dietitian to plan kidney-friendly meals
- Exercise regularly (aim for 30 minutes most days)
- Get enough sleep and manage stress
- Stay connected with your healthcare team
Diet and exercise
A kidney-friendly diet often limits salt, potassium, and phosphorus. Your doctor or dietitian can give you specific advice. Regular physical activity helps control blood pressure and weight.
Mental health and emotional wellbeing
Coping with a chronic condition can be stressful. It’s normal to feel anxious or down. Talk to your doctor or a mental health professional. If you’re in crisis, reach out for support immediately.
Prevention
You cannot always prevent kidney disease, but you can reduce your risk by managing blood pressure, controlling diabetes, eating a healthy diet, and staying active.
Vaccines
Get recommended vaccines like flu and pneumonia, as infections can be harder on your kidneys.
Screening programmes
If you have risk factors like diabetes or high blood pressure, your doctor may recommend regular kidney blood tests to catch problems early.
Complications
If left untreated
- Chronic kidney disease can progress to kidney failure
- Heart disease and stroke are more likely
- Anemia (low red blood cells) can develop
- Bone disease from mineral imbalances
Long-term outlook
With early detection and good management, many people with kidney disease live full lives. Treatment has improved greatly. Your healthcare team will work with you to slow the disease and keep you as healthy as possible.
Find support
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Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
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Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 18, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.