Kidney function test
A private kidney function blood test to check filtration and waste markers such as creatinine, eGFR, urea and electrolytes where included.
Book a GP blood test appointment if you need kidney markers checked, have symptoms, take medication requiring monitoring or want previous results explained.
Test options
Kidney function blood test
Use the options below if you already know which test you need. If you are unsure, book a GP blood test appointment and your GP can advise.
Kidney and liver function
Glucose, triglycerides & cholesterol
Red cells, white cells, platelets, haemoglobin
Haematocrit, mean cell volume, mean haemoglobin
Kidney and liver function
Glucose, triglycerides & cholesterol
Sodium
Potassium
Chloride
Bicarbonate
Urea
Creatinine
From booking to results
Your appointment, step by step
Book online, see a GP, have your sample taken during the appointment and view your results securely in your DocTap account.
- 1Book online in minutesChoose your preferred clinic and time, and select a male or female clinician where available. You will get instant confirmation.
- 2We will tell you how to prepareMost blood tests do not need fasting. If a test needs anything specific beforehand, we will let you know before your appointment.
- 3See a GP and have your sample takenYour appointment includes a 15-minute GP consultation to discuss symptoms, check suitability or advise which test you need. A quick blood sample is then taken from your arm.
- 4Get results and follow-upYou will get a message when your result is ready. Your results and doctor's report will be available securely in your DocTap account; abnormal results are prioritised and your clinician will contact you if urgent action is needed.
What it can show
What a kidney function test shows
Kidney blood tests look at filtration, waste products and sometimes mineral balance.
Creatinine and eGFR
Creatinine is a waste product from muscle activity. Your result can be used to estimate eGFR, which gives an indication of how well your kidneys are filtering. eGFR is more useful when interpreted with age, sex, body size and previous results.
Urea and electrolytes
Urea can be affected by kidney function, hydration and diet. Electrolytes such as sodium and potassium help show mineral balance and can be important if you are dehydrated, unwell or taking certain medicines.
Context changes the meaning
Hydration, muscle mass, recent illness, medication and supplements can all affect kidney markers. A single result is helpful, but the trend over time often tells the clearer story.
When to test
When kidney function is worth checking
Kidney function is commonly checked when risk factors, symptoms or medication make it relevant.
Blood pressure, diabetes or heart risk
High blood pressure and diabetes are common reasons to check kidney function. Kidney markers are often reviewed alongside cholesterol, HbA1c and urine tests because these risks can sit together.
Medication monitoring
Some medicines need kidney function checks before starting or during treatment. This can include certain blood pressure medicines, anti-inflammatory medicines or other regular prescriptions, depending on your situation.
Dehydration, urinary symptoms or previous results
Testing may be useful after vomiting, diarrhoea, dehydration, urinary symptoms, kidney-stone symptoms or a previous abnormal result. If symptoms are severe, urgent care may be more appropriate than a routine blood test.
Results
Understanding kidney results
Kidney results are best interpreted as part of a bigger picture.
One eGFR result is not the whole story
A lower eGFR may need repeating, especially if you were dehydrated or unwell. Your GP may compare with older results to see whether the result is stable, improving or changing.
What may be checked next
Depending on the result, your GP may suggest a urine ACR test, blood pressure check, repeat kidney function, diabetes testing, medication review or further investigation.
Electrolytes can need quicker action
Potassium, sodium and other electrolytes can sometimes be clinically important if very high or very low. Your GP will advise if a result needs prompt repeat testing, medication changes or urgent assessment.
Clinical quality
The standards behind every test
The clinical standards behind every DocTap blood test, across our London clinics.
- CQC rated ‘Good’.
- Independently inspected and regulated by the Care Quality Commission.
- Fully GMC-registered doctors.
- UK-trained and experienced GPs only.
- Every consultation reviewed.
- Each one is checked for quality and safety, overseen by our Medical Director.
- No sales incentives.
- Our GPs are never paid commissions for tests or treatments.
Ready to book?
Book a GP blood test appointment, or compare prices for other blood tests.
11 locations where we test
DocTap London clinics and on-site laboratories
Canary Wharf
Situated by South Quay Footbridge, a 3-minute walk from Canary Wharf and Heron Quays stations.
Hammersmith
Situated on King Street, a 6-minute walk from Hammersmith underground stations.
Kings Cross & Euston
Located just off Euston Road, less than a 10-minute walk from both Euston and King’s Cross stations.
Liverpool Street & Bank
Located in the heart of the City, a 5-minute walk from Liverpool Street and Bank stations.
London Bridge
Located just off Borough High Street, an 8-minute walk from London Bridge station.
Bond Street
Located on Wigmore Street, just off Harley Street, a 7-minute walk from Bond Street station.
Clapham
Located on Clapham High Street, only a 3-minute walk from Clapham Common station.
Old Street
Located off Old Street, a 3-minute walk from Old Street underground station.
Stratford
Located within The Conductor building, a 6-minute walk from Stratford station, or 3 minutes from the Westfield shopping centre.
Swiss Cottage
Only a 3-minute walk from Swiss Cottage station.
Victoria
Situated on Lower Belgrave Street, a 5-minute walk from Victoria rail and underground stations.
Online GP
Speak to a GP by video or phone, wherever you are — no app needed. Ideal for follow-ups and straightforward concerns.