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The Comprehensive Guide to Home Kidney Function Testing in the UK

The Comprehensive Guide to Home Kidney Function Testing in the UK

Maintaining optimal kidney health is vital for overall well-being. The kidneys play a crucial role in filtering waste products, balancing electrolytes, regulating blood pressure, and producing hormones that promote red blood cell production. However, how can you determine if your kidneys are functioning properly? This is where home kidney function testing comes into play. In the UK, there are various options available for home kidney function testing, but understanding the different tests and interpreting the results can be overwhelming.

Before we start, as with all of the tests, if you do have symptoms you are testing for - please speak to your GP. No test is an island, and interpretation is vital. This is best done by someone who knows your medical history - i.e. your GP. Where we come in is the testing part - quick, effortless and most importantly - accurute.

So, onwards! To help you navigate this topic effectively, we have created the ultimate guide to home kidney function testing in the UK. From gaining insights into kidney function to selecting the most suitable test for your needs, we will provide you with all the necessary information to take charge of your kidney health from the comfort of your own home. Let's delve into the guide and embark on the journey towards healthier kidneys.

The Importance of Home Kidney Function Testing

Your kidneys are vital organs that perform essential functions, including filtering waste and excess fluid from the blood, maintaining proper electrolyte balance, and regulating blood pressure. When the kidneys are healthy, they efficiently eliminate waste products. However, when kidney function is compromised, it can lead to the accumulation of toxins and fluid imbalances, resulting in various health issues.

Home kidney function testing plays a crucial role in monitoring the health of your kidneys. By regularly conducting kidney function tests, you can identify potential problems at an early stage and take proactive steps to prevent further deterioration. Home kidney function tests are convenient, affordable, and user-friendly, making them an excellent option for individuals who want to actively manage their kidney health.

Understanding Kidney Function Tests

Before exploring the different types of home kidney function tests available in the UK, it is essential to comprehend what kidney function tests are and how they operate. Kidney function tests are a group of laboratory tests that evaluate the performance of the kidneys. These tests measure various substances in the blood and urine that reflect kidney function and overall kidney health.

Several types of kidney function tests exist, each assessing different aspects of kidney function. Some common kidney function tests include:

  1. Kidney Function Blood Test. This is an excellent starting point with 4 key biomarkers to test your kidney function. 
  2. Blood urea nitrogen (BUN) test: Measures the level of urea nitrogen in the blood, which indicates how effectively the kidneys eliminate nitrogenous waste products.
  3. Creatinine test: Measures the level of creatinine in the blood, a byproduct of muscle metabolism that serves as an indicator of kidney function.
  4. Glomerular filtration rate (GFR) test: Estimates how efficiently the kidneys filter waste products from the blood by calculating the rate at which blood is cleared of a waste substance called creatinine.
  5. Urinalysis: Analyzes the composition of urine, including the presence of protein, blood cells, and other substances that can indicate kidney damage or dysfunction.
  6. Albumin-to-creatinine ratio (ACR) test: Measures the levels of albumin (a protein) and creatinine in the urine to detect early signs of kidney damage or dysfunction.
  7. Electrolyte tests: Assess the levels of electrolytes such as sodium, potassium, and bicarbonate in the blood, which can indicate electrolyte imbalances resulting from kidney dysfunction.

Types of Home Kidney Function Tests Available in the UK

Now that you have a basic understanding of kidney function tests, let's explore the different types of home kidney function tests available in the UK. Here are some common options, each with its own advantages and limitations:

  1. Home blood test kits: These kits allow you to collect a small blood sample at home, usually by pricking your finger, and send it to a laboratory for analysis. The laboratory will measure parameters like BUN, creatinine, and electrolyte levels in your blood.
  2. Home urine test kits: These kits enable you to collect a urine sample at home and measure various parameters, such as protein levels, pH, and the presence of blood or glucose. They often include test strips or dipsticks that change color to indicate specific levels or the presence of substances in the urine.
  3. Home creatinine clearance test: This test involves collecting urine samples over a specified time period (e.g., 24 hours) and comparing the creatinine levels in the urine with the creatinine level in a blood sample. It provides a more accurate estimate of kidney function than single-time-point tests.
  4. Home kidney imaging tests: Although not as common for home use, certain portable ultrasound devices may be available for at-home kidney imaging. These devices can help visualize the kidneys and identify potential abnormalities.

With all of the above, the most accessible form is clearly the home blood test kits. It's quick and simple.


When choosing a laboratory to do your testing it is vitally important to make sure that the machines are calibrated for both capillary and venous samples. This makes all the difference. Traditionally all blood tests are geared towards the venous sampling methods, i.e. larger amount of blood in a venous sample, taken from the vein by a phlebotomist. 

Capillary blood (taken from a finger) is, of course, different, starting with the volumes and other factors, such as clotting and rate of hemolysis. This needs taking into account when choosing your lab - make sure it can specifically treat capillary samples and is calibrated/assessed for the capillary samples.

One Day Tests uses Sussex Pathology Diagnostics Laboratory, which has undergone extensive investment into the capillary sampling. And it is all available to you now, at your home, via our home kits!

Preparing for a Home Kidney Function Test

Before conducting a home kidney function test, there are a few steps to follow in preparation. These steps may vary depending on the specific test you choose. Here are some general guidelines:

  1. Read the instructions carefully: Thoroughly review the instructions provided with your chosen test kit to ensure you understand how to collect the required sample and interpret the results accurately.
  2. Stay hydrated: Adequate hydration is crucial for producing a good blood sample. Drink sufficient fluids before collecting urine, as per the instructions provided with your test kit.
  3. If you have recently taken the antibiotic trimethoprim (usually for a urinary tract infection), delay taking this test for a couple of weeks.
  4. Watch a video on how best to perform a home sample collection from Dr. Adam Staten, a practicing GP and Clinical Director at One Day Tests.

Interpreting Home Kidney Function Test Results

After conducting your home kidney function test and sending the samples for analysis (make sure you follow the instructions!), you will receive the results. It's essential to interpret the results correctly. Here's a general guideline:

  1. Reference ranges: The test results will typically include reference or normal ranges for each parameter measured. These ranges indicate the expected values for individuals with healthy kidney function. You will have this in the report that is sent to you by the laboratory.
  2. Comparison to reference ranges: Compare your test results to the reference ranges provided. Results within the reference range generally suggest normal kidney function.
  3. Read interpretations of your results on the Health Dashboard.
  4. Speak to your GP. If your test results fall outside the reference range or if you have any concerns, it's important to consult your GP for further evaluation and guidance. They can provide expert advice and recommend appropriate steps to address any abnormalities.

When to Seek Medical Advice

While home kidney function testing can be valuable for monitoring your kidney health, there are instances when it's essential to seek medical advice. Speak to your GP if you experience any of the following symptoms:

  1. Persistent changes in urination patterns: These include increased frequency, decreased urine output, blood in the urine, or difficulty urinating.
  2. Swelling or edema: Noticeable swelling in the legs, ankles, feet, face, or hands may indicate kidney problems.
  3. Fatigue and weakness: Persistent tiredness or weakness that affects your daily activities.
  4. Persistent pain: Pain or discomfort in the lower back or sides.
  5. Hypertension: Consistently high blood pressure readings.
  6. Recurring urinary tract infections (UTIs): Frequent or recurrent UTIs may be indicative of underlying kidney issues.

We are here for you - to get a great partnership going between us, you and your GP. If you have any questions, please do not hesitate to contact us, we are here to help!

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