Blood sample collection options

You can choose your preferred collection method when you checkout

Finger prick kit (FREE)

You can do this test at home without the need for a doctor. We'll send you everything you need to collect your sample and post it back to us. And it's all included in the cost. We've put together a video that covers the process, making it easy to check and track your health from home.

Home nurse appointment (+£45) was £60

We'll arrange for a medical professional to visit your home and collect your sample. This is great if you're unsure on how it all works or have trouble collecting a sample. No need to book a doctor's appointment or visit a clinic, we'll send you everything you need to collect a sample and post it back to our labs.

Visit a partner clinic (+£45)

Once you've ordered your test, look out for an email from our phlebotomy partners containing information and a link to book your appointment. We'll send you everything the clinic will need to complete the sample and post it back to our labs.

Organise a nurse myself (FREE)

If none of the above options work for you, you can arrange your own medical professional to collect your sample. There is no additional charge for this. Once you've ordered your test, we'll send you everything you and your chosen medical professional will need to collect a sample and post it back to our labs.

Still unsure how it works? You can find more information on collection methods and the service we provide in our 'How it Works' section.

What gets tested?

10 Biomarkers

Additional biomarkers can be added by personalising this test.

What are biomarkers?

Biomarkers are specific compounds we can detect in your blood sample that reflect different things about your health. Your test will tell you your levels for each of the above biomarkers, and whether they are in a normal range.

About flexible subscriptions

How does a subscription work?

When you purchase this test subscription plan, we will automatically send you another test kit in a few months. Don't worry - you have full control over when this will be, and you can change/cancel it anytime.

When you first purchase this test, you can choose your subscription options in the checkout. We do this, because we recommend taking multiple tests over time to track how your biomarkers change. You'll be charged per test kit (rather than monthly, for example).

Why subscribe to multiple tests?

One test will show you what areas you need to focus on, continued testing will help you learn how your training, diet and lifestyle is impacting your health.

How often should I test?

We recommend a follow up test 3 months after your first test, followed by a test every 6 months depending on your results, but its up to you!

Can I change what's tested in future tests?

Yes, you can tailor/customise subsequent tests (via your app) to focus on just the areas that need improving.

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Forth home blood test kit with yellow tube
Kidney blood test - Go beyond reporting basic blood results
Hand holding a lancet up to a finger on the other hand
Kidney blood test - Personalised targets
Kidney blood test - Focus where it counts
Kidney blood test - Guidance for optimal health
Analysed by
NHS Lab
Tracked 24
delivery
Personalised
GP advice
Finger prick or venous collection

Kidney Function Blood Test

Trustpilot 4 stars

Results in 2 working days

10 Biomarkers

Check and monitor your kidney health with a renal blood test from the comfort of home. Our kidney function blood test measures key markers like creatinine and eGFR to help detect early signs of kidney issues. With fast, lab-certified results and expert insights, you can take charge of your well-being without visiting a doctor.

Analysed by
NHS Lab
Tracked 24
delivery
Finger prick or venous collection

£49

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What gets tested?

10 Biomarkers

Blood sample collection options

WHEN TO TAKE THE TEST?

If you have consumed a large amount of alcohol, we recommend leaving a gap of 72-96 hours before taking this test.

1 Million+

results delivered

As seen in

As seen in
Urea levels in men and women, UK 2025

Monitoring Your Kidney Health

Poor diet, dehydration, high salt intake, and excessive alcohol can all impact your kidney function.

Our kidney function blood test can be done at home or one of our partner clinics, making it an easy and convenient way to proactively manage your kidney health. The at-home kit includes everything you need to collect a small blood sample and post it back to our labs for analysis.

Kidney disease can develop silently, with no obvious symptoms until it’s too late. A simple blood test can identify issues before they become serious. And with HealthCoach, you’ll get personalised insights and recommendations to help you manage your renal function.
Our data shows that only 27% of adults have a urea level in the “Excellent” range[1].

[1]Based on 3,096 HealthCoach reports from Forth customers, February 2025

What this Kidney Function Blood Test measures

10 Biomarkers

Alanine Aminotransferase (ALT)

Alanine aminotransferase (ALT) is an enzyme primarily found in the liver. Only small amounts are usually found in the blood. However, if the liver or muscles are damaged an increased level of ALT will be released into the bloodstream. Elevated ALT levels can be caused by alcohol, fatty liver, viruses, or intense exercise.

Alkaline Phosphatase (ALP)

Alkaline phosphatase (ALP) is an enzyme found in high concentrations in the bones and liver. It is measured in liver function tests to assess liver health. Elevated ALP levels can indicate liver diseases such as hepatitis, cirrhosis, or bile duct obstruction​.

Albumin

Albumin is a protein produced by the liver, crucial for maintaining blood volume and pressure. Low albumin levels can indicate liver dysfunction, as the liver's ability to synthesize this protein is compromised. Monitoring albumin helps assess liver health, diagnosing conditions like cirrhosis, hepatitis, and other liver diseases​.

Gamma GT (GGT)

Gamma-glutamyl transferase (GGT) is an enzyme found mainly in the liver. The concentration of GGT within the bloodstream increases when there is either damage to the liver or bile ducts, or when there is increased production of GGT within the liver. This can occur due to taking many medications, smoking, poorly controlled diabetes and excessive alcohol consumption.

Globulin

Globulins are proteins produced by the liver and immune system and is a general term to describe more than 60 proteins. Measuring globulin in liver health tests is important in the assessment of liver function. Abnormal globulin levels can indicate liver dysfunction or chronic liver diseases like cirrhosis or hepatitis.

Total Protein

Total protein test measures the quantity of protein present within your bloodstream and is a combination of both albumin and globulin levels. Measuring total protein in liver function tests assesses the liver's ability to synthesize proteins, indicating liver health, nutritional status, and helping to identify liver diseases like cirrhosis and hepatitis.

Creatinine

Creatinine is a waste product which is produced by muscles when they break down creatine. It is excreted from the body by our kidneys in urine. Therefore, the levels of creatinine can give a good indication of how effectively the kidneys are working. Elevated levels suggest potential kidney stress or increased muscle metabolism.

eGFR

Estimated glomerular filtration rate (eGFR) measures how well the kidneys filter waste from the blood. It helps detect kidney disease early and can provide an overall assessment of kidney function. The calculation is based on levels of creatinine and results can be influenced by a number of factors including muscle mass, weight and hydration.

Urea

Both urea and creatinine are good indicators of whether the kidneys are working properly. Urea is a waste product formed in the liver when protein is metabolised. It is released into the bloodstream and carried to the kidneys where it is expelled within urine. If the kidneys are not performing correctly the level of urea will rise.

Uric Acid

Uric acid or urate is a natural waste product produced when the body breaks down purines. Most uric acid is removed from the body by the kidneys. Too much uric acid can lead to the formation of solid crystals in the joints - known as gout. High levels can also lead to the formation of kidney stones.

How our Kidney Function Blood Test works

Getting the insights you need to improve your health has never been easier.

How it works - collect your sample

Collect your blood sample

Collect a small blood sample and post it to our accredited labs for analysis using the Tracked24 envelope included in your kit.

How it works - view your results

Get fast, accurate results

You’ll receive a detailed report with your personalised scores, insights into your kidney function, including doctor-reviewed comments.

How it works - make improvements

Improve your immune health

Your results highlight areas needing attention, giving you the data to seek further help.

Only 27% of Forth customers have ‘Excellent’ urea scores. Improve your kidney function with HealthCoach.

HealthCoach gives you the power to change your health. Unlock your kidney scores, personalised insights and goals to aim for.

Unlock your health scores

Kidney health score - 63/100

Translates biomarker results into health score for kidney health

Personalised health targets

Urea

HEALTHY
Healthy result range

2.5 (mmol/L)

Next target 2.3 - 5.6 (mmol/L)

Get incremental, achievable targets based on your unique results, ensuring progress at every step

Focus where it counts

22

100

Creatinine

NEEDS ATTENTION

76

100

Urea

GOOD

HealthCoach's smart algorithms identify the specific areas which will make the biggest impact on your journey to better health

Guidance for optimal health

22

100

Creatinine

NEEDS ATTENTION
Dr Thom Phillips

Your healthy level of creatinine will be supported by maintaining a balance of lifestyle factors, including strength exercise and consistent nutritional intake to match your personal demand.

Get tailored advice which considers your gender, age, hormone treatments and menstrual cycle to help you reach optimal health

Kidney Function Blood Test, recommended by our doctors

"A renal function test assesses how well your kidneys are working. It typically involves measuring creatinine and blood urea nitrogen levels in your blood. These values help determine if your kidneys are effectively filtering waste and regulating the balance of fluids and electrolytes in your body. Abnormal results may indicate kidney problems."

Dr Thom Phillips

Dr Thom Phillips

Clinical lead

Frequently asked questions

This is what our customers ask us about the most. For more information, try our help centre.

What does this test check?

This kidney function blood test helps detect a range of potential kidney-related health issues:

  • Chronic Kidney Disease (CKD): High creatinine levels and a low eGFR can indicate reduced kidney function, a sign of CKD.
  • Dehydration or Poor Kidney Filtration: High urea levels can suggest dehydration, poor filtration, or kidney stress.
  • Protein Imbalance & Kidney Damage: Low albumin and abnormal total protein levels may indicate kidney disease.
  • Liver-Kidney Connection Issues: Elevated ALT, ALP, and Gamma GT levels can point to liver dysfunction, which may impact kidney performance.
  • Uric Acid Build-Up & Gout Risk: High uric acid levels may suggest kidney inefficiency in removing waste, increasing the risk of gout and kidney stones. High levels of Uric Acid have also been linked to the development of Atrial Fibrillation.

While this test can indicate an increased risk of kidney stones (due to high uric acid levels), it does not directly diagnose existing stones. If kidney stones are suspected, further imaging tests such as an ultrasound or CT scan may be required.

By analysing these biomarkers, this renal blood test provides a detailed picture of kidney health, helping to detect potential issues early so you can take proactive steps to protect your well-being.

Can I check kidney function at home?

Yes – our kidney function test can be done at home using a fingerprick kit. The kit comes with everything you need to collect a small blood sample from the tip of your finger.

We also offer the option to have a trained healthcare professional (phlebotomist) visit you home to collect the blood from your vein (called a venous draw).

What is the function of the kidneys?

Your kidneys filter waste, balance fluids, regulate blood pressure, and support red blood cell production. They also help maintain strong bones and overall well-being. Keeping them healthy with hydration, a balanced diet, and regular checks is key to preventing future issues.

What causes kidney disease?

Kidney disease develops when the kidneys are damaged by high blood pressure, diabetes, infections, or lifestyle factors like dehydration and poor diet. Because it often has no early symptoms, kidney problems can go unnoticed. Regular testing helps detect issues early, giving you the chance to take action before damage worsens.

What are the warning signs of kidney disease?

Early kidney disease is often symptomless, but warning signs include fatigue, swelling, changes in urination, puffiness around the eyes, and high blood pressure. As kidney function declines, symptoms worsen. Regular blood tests can detect problems early, helping you take control of your kidney health before complications arise.

How can I reduce my risk of kidney disease naturally?

Stay hydrated, eat a balanced diet, and manage blood pressure and blood sugar levels. Avoid excessive salt, alcohol, and smoking while maintaining a healthy weight. Regular health checks help catch problems early, giving you the best chance to protect your kidney function and overall well-being.

How and when will I get my results?

Your results are delivered to your account and can be viewed on the Forth app. We aim to get your results to you 2 working days from the date your sample reaches our lab.

How soon will the test arrive?

Once you place your order, your test kit will be dispatched the same day (if ordered before 3 pm on weekdays) via Royal Mail Tracked-24, meaning you should receive it within 1-2 days.

What is a health score?

Your health score is a personalised rating based on your test results. Scores range from 0 (poor) to 100 (excellent). It helps you understand how well your kidneys are functioning and highlights any areas that may need improvement.

Health sores are included at no extra cost and can be viewed in our app.

How often should I check my kidney health?

If you have risk factors like high blood pressure, diabetes, or a family history of kidney disease, we recommend testing every 6 months. Regular checks help catch potential issues early, giving you the best chance to protect your kidney health.

Is your packaging discreet?

Yes, all of our test kits are sent in plain, unbranded packaging for complete privacy. There are no logos or markings that indicate the contents, ensuring a discreet and confidential delivery. Your test results are also stored securely in your online account, accessible only to you.

We are dedicated to supporting you on improving your health

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What customers say about our Kidney Function Blood Test

Kidney Function Blood Test