Private Kidney Function Test (U&E and eGFR): £40, results in 24 hours
Creatinine, eGFR, urea and electrolytes from one sample, £40
The standard kidney blood test, also called a renal profile or U&E: creatinine and your estimated GFR (how well the kidneys are filtering), urea, and the two electrolytes the kidneys control, sodium and potassium. Reviewed by a doctor, with results emailed within 24 hours. No fasting and no GP referral needed. Have your blood taken at our Kings Heath clinic in Birmingham with no blood-draw fee, at one of 100+ partner clinics across the UK, or at home.
Includes: all 5 markers including the calculated eGFR, the lab fee, a doctor’s review of your results and a written report by email, usually within 24 hours. Nothing to pay on the day at the Birmingham clinic.
Book a kidney function test online- No referral needed
- No fasting
- Results in 24 hours
- Doctor-reviewed
- CQC-registered clinic
What a kidney function test checks
Kidney function is measured indirectly: the kidneys clear waste products from the blood, so the level of those waste products shows how well they are filtering. Creatinine is the key one, and the eGFR turns it into a filtering rate adjusted for your age and sex. The electrolytes show whether the kidneys are keeping the blood’s salt and potassium in balance.
- Creatinine a waste product of muscle, cleared by the kidneys. It is the core kidney marker: the level rises as kidney filtering falls. It also runs higher in muscular people and after creatine supplements or a large meat meal, which is why it is read with the eGFR.
- estimated GFR the estimated glomerular filtration rate, calculated from your creatinine, age and sex: how many millilitres of blood your kidneys filter each minute. Above 90 is normal; 60 to 89 is mildly reduced and common with age; below 60 for three months or more defines chronic kidney disease.
- Urea the waste product of protein breakdown, also cleared by the kidneys. It rises with reduced kidney function but also with dehydration, a high-protein diet and bleeding into the gut, so it is read alongside creatinine.
- Sodium the main salt in the blood, controlled by the kidneys and by how much water you hold. Low sodium follows some medicines (diuretics, antidepressants), heart or liver disease or drinking large volumes; high sodium means dehydration.
- Potassium the mineral that keeps the heart rhythm and muscles working. The kidneys control it tightly; it rises with kidney disease and some blood-pressure tablets and falls with diuretics, vomiting or diarrhoea. A result far outside the range is treated as urgent.
When to have one
Kidney disease causes no symptoms until it is advanced, which is why it is nearly always found on a blood test. A kidney function test is worth having if any of these apply:
- You have high blood pressure or type 2 diabetes, the two commonest causes of kidney damage, and have not had your kidneys checked in the past year
- You take a medicine that can affect the kidneys or needs kidney monitoring: ibuprofen or naproxen regularly, blood-pressure tablets (ACE inhibitors, ARBs, diuretics), lithium, metformin, or a weight-loss injection
- You use protein or creatine supplements, anabolic steroids, or a high-protein diet and want to know the effect
- You have swollen ankles, foamy urine, passing urine more often at night, tiredness or itching, which can come from the kidneys
- A family member has kidney disease, or you have had kidney stones or repeated urine infections
- You want a baseline as part of a general health check, before a new training programme, or before starting a medicine that needs one
What happens
- Book online and choose where to have your blood taken: the Kings Heath clinic, a partner clinic near you or a home visit. Pay once; there is nothing to pay on the day.
- Give one small blood sample. It takes a few minutes. No fasting is needed for this test.
- The lab measures the five markers at a UKAS-accredited laboratory and calculates your eGFR from the creatinine, your age and your sex.
- A doctor reviews your results and emails you a written report, usually within 24 hours, with each result against the normal range and a comment on anything outside it. A potassium or sodium far outside the range is phoned through the same day.
- If something needs following up, the report says what and why: usually a repeat test in three months, a urine test for protein, or blood pressure and diabetes checks. You can book the next test or a GP appointment online, and we write to your NHS GP with your consent.
How to prepare
- No fasting. Eat and drink normally and take your usual medicines.
- Drink normally. Being dehydrated on the day pushes urea and creatinine up and makes the kidneys look worse than they are.
- Avoid a heavy gym session and a large meat meal the day before, and skip creatine for 48 hours if you take it: all three raise creatinine without any change in your kidneys.
- Bring a list of medicines and supplements, especially anti-inflammatories, blood-pressure tablets and protein or creatine products.
Where to have your blood taken
The test, the laboratory and the doctor’s report are the same wherever you live. Only the blood-draw fee differs, and it is charged once per visit however many tests you add.
Want more from the same sample? Add a liver function test, full blood count or HbA1c and cholesterol and the blood is taken once, with the multi-test discount applied at checkout.
Normal ranges and what a high result means
| Marker | Typical adult range |
|---|---|
| Creatinine | 60 to 110 µmol/L (men), 45 to 90 µmol/L (women) |
| eGFR | above 90 mL/min normal; 60 to 89 mildly reduced; below 60 reduced |
| Urea | 2.5 to 7.8 mmol/L |
| Sodium | 133 to 146 mmol/L |
| Potassium | 3.5 to 5.3 mmol/L |
Typical adult ranges. Every laboratory sets its own, which can differ slightly from these, and your report shows the range the lab used. Creatinine depends on muscle mass, so a muscular man can sit above the range with healthy kidneys and a small older woman can have kidney disease with a creatinine inside it: that is what the eGFR corrects for.
Most kidney results outside the range are mild and have an explanation: dehydration, a recent heavy workout, creatine, an anti-inflammatory, or simply age (eGFR falls slowly from the forties, and 60 to 89 is common and usually harmless in older people). What matters is whether a reduced eGFR is confirmed on a repeat test three months later, whether there is protein in the urine, and whether blood pressure and blood sugar are controlled. These are the tests we add when a result needs explaining, all bookable at the same clinic:
Questions people ask
What is a kidney function test and what does it show?
A kidney function test, also called a renal profile or U&E (urea and electrolytes), is a blood test that measures creatinine, urea, sodium and potassium and calculates your eGFR, the rate at which your kidneys filter the blood. It shows whether the kidneys are clearing waste normally, whether they are keeping the blood’s salt and potassium in balance, and, with a repeat test, whether kidney function is stable or falling. It is the standard check for people with high blood pressure or diabetes and for anyone on a medicine that can affect the kidneys.
What is a normal eGFR?
An eGFR above 90 mL/min is normal. Between 60 and 89 is mildly reduced, which is common from middle age onwards and usually means nothing on its own unless there is also protein in the urine. Below 60 on two tests at least three months apart is the definition of chronic kidney disease, which is graded by how far below 60 it is. The eGFR is calculated from your creatinine, age and sex, so the same creatinine gives a lower eGFR in an older person.
What is a normal creatinine level?
Roughly 60 to 110 micromoles per litre for men and 45 to 90 for women, though each laboratory sets its own range and your report shows the one used. Creatinine comes from muscle, so a muscular man naturally runs higher and a slight older woman lower; that is why the result is always read with the eGFR rather than on its own.
What does a high creatinine mean?
Either the kidneys are filtering less than they should, or something has raised creatinine without the kidneys being involved: dehydration, a heavy workout in the past day or two, creatine supplements, a large meat meal, anabolic steroids, or an anti-inflammatory such as ibuprofen. The eGFR, the urea and your history separate the two. A mildly raised creatinine is repeated after three months, well hydrated and rested; a markedly raised one is followed up straight away.
How can I lower my creatinine or improve my kidney function?
If the rise is from dehydration, exercise, creatine or anti-inflammatories, it settles once the cause is removed and the repeat test shows it. If the kidneys are genuinely under strain, the things that protect them are controlling blood pressure (below 140/90, lower in diabetes), controlling blood sugar, stopping smoking, keeping to a healthy weight, avoiding regular ibuprofen and naproxen, and keeping well hydrated. There is no supplement or diet that lowers creatinine by itself, and anything that promises to is best avoided. Kidney damage that is caught early can usually be held stable for decades.
How much does a private kidney function test cost?
£40 at OneMedicine, which includes the laboratory fee, the calculated eGFR, a doctor’s review and a written report by email. There is no blood-draw fee at our Birmingham clinic. At a partner clinic elsewhere in the UK the blood-draw fee is £29, and a home visit in England is £60, charged once per visit however many tests you have.
Do I need to fast before a kidney function test?
No. Eat and drink normally and take your usual medicines. Do drink normally in the 24 hours before, avoid a heavy gym session and a large meat meal the day before, and leave creatine for 48 hours, as all of these push creatinine up without any change in your kidneys.
How long do kidney function test results take?
Results are usually emailed within 24 hours of the sample reaching the lab, often the same evening for a sample taken at the Birmingham clinic. Samples from partner clinics and home visits are couriered to the same laboratory and typically take one to two working days. A sodium or potassium far outside the range is phoned through the same day.
Can I check my kidney function at home?
Home finger-prick kits for creatinine are not reliable enough to act on, and a urine dipstick only shows protein or blood, not filtering rate. The accurate test is a venous blood sample. If getting to a clinic is difficult, book a home visit and a phlebotomist takes the sample at your home anywhere in England; the laboratory and the doctor’s report are the same.
Should I test my liver and kidneys together?
Often, yes. Kidney and liver function are the two organ checks most medicines need, and they come from the same blood sample, so adding the liver function test costs £40 more with no extra blood draw. The full blood count is the third test usually paired with them, and the three together are the standard pre-operation and medication-monitoring set.
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OneMedicine, 1 High Street, Kings Heath, Birmingham B14 7AR. Opposite Kings Heath railway station, on-site parking. CQC-registered.
