A kidney result flagged on an executive blood test deserves a clear explanation, especially when you feel well. Creatinine and estimated glomerular filtration rate, usually shortened to eGFR, help a doctor assess kidney function. Their meaning depends on your previous results, urine testing, medicines and current health. One number is the beginning of an assessment, not a diagnosis on its own.
The Wellness offers doctor-led blood testing and results review in London. A useful review connects the laboratory report with a decision: whether you need an early repeat, a urine albumin test, a medication review or specialist assessment. It also makes clear who will review the next result, so an important finding does not disappear into a busy diary.
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What creatinine and eGFR measure
Creatinine is a waste product associated with muscle metabolism that the kidneys remove from the blood. Laboratories use creatinine with other information to estimate the kidneys' filtering capacity. The result is reported as eGFR, usually in ml/min/1.73 m². It is an estimate, not a direct measurement of every aspect of kidney health.
Creatinine and eGFR therefore belong together. A higher creatinine may produce a lower eGFR, but the same creatinine result does not mean exactly the same thing for every person. Muscle mass and the circumstances of the blood test can affect interpretation. A doctor should also consider whether your kidney function is stable or changing.
NICE guidance on chronic kidney disease explains that creatinine-based eGFR can be less reliable in situations including acute kidney injury, pregnancy, muscle wasting and higher muscle mass. This matters for people who strength train, use protein supplements or have lost substantial muscle. It is a reason for careful assessment, rather than automatic reassurance or automatic labelling.
A low eGFR does not automatically mean chronic kidney disease
Chronic kidney disease describes abnormalities of kidney structure or function present for more than three months, with implications for health. NICE includes an eGFR below 60 on at least two occasions separated by at least 90 days within that definition, with or without other markers of kidney damage.
That definition should not be confused with the timing of the first follow-up. For an adult not previously tested who has an eGFR below 60, NICE recommends repeating the test within two weeks. The purpose is to confirm the result and help identify acute deterioration. A doctor may need to act sooner when the result, symptoms or clinical circumstances are concerning.
The distinction is important. Waiting three months without assessment is not the right response to a newly low result. Equally, a single mildly reduced estimate does not establish a lifelong diagnosis. A well-organised review explains both the immediate plan and what would be needed to determine whether a change is persistent.
Why a urine test can add information a blood test cannot
A kidney assessment often needs both a blood result and a urine result. The urine albumin-to-creatinine ratio, or ACR, measures albumin in relation to creatinine in a urine sample. It helps identify albumin leakage, which can be a marker of kidney damage even when filtration is relatively preserved.
NICE recommends urine ACR testing in adults with diabetes, adults with eGFR below 60, and people with eGFR of 60 or above when there is a strong suspicion of chronic kidney disease. An ACR between 3 and 70 mg/mmol should usually be confirmed in a subsequent early-morning sample; NICE does not require that repeat when the initial ACR is 70 mg/mmol or more. The doctor still needs to interpret the result in context.
This is why a reassuring eGFR cannot answer every kidney question. A person can have a relatively preserved filtration estimate and another marker of kidney disease. Conversely, a mildly reduced eGFR without albuminuria may have a different significance from the same eGFR accompanied by a high ACR. The combination helps guide follow-up and referral.
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What an eGFR between 60 and 89 means
An eGFR between 60 and 89 is not, on its own, enough to diagnose chronic kidney disease. The doctor considers other evidence of kidney damage, previous measurements and the wider clinical picture. NICE also advises caution when interpreting estimates of 60 or above because the estimate becomes less accurate as true filtration increases.
A laboratory may display a result as greater than 90 rather than a more precise figure. That is not missing information that needs a larger panel to fill it. It reflects the limitations of the estimate. The useful question is whether the overall assessment identifies kidney disease or a meaningful change that requires action.
For an executive health review, the aim is a proportionate plan. Someone with stable results, no relevant urine abnormality and no concerning history may need a different follow-up from someone with diabetes, high blood pressure, blood in the urine or a falling trend. The appointment should explain which situation applies to you and why.
Medicines, supplements and the circumstances of the test
A review includes prescribed medicines, over-the-counter painkillers and supplements. Some medicines can affect kidney function or change the interpretation of a result. Non-steroidal anti-inflammatory drugs, such as ibuprofen, are particularly relevant to discuss, including when they are taken intermittently for training injuries or joint pain.
Do not stop prescribed treatment because a result is highlighted on a report. Some medicines require a planned blood-test check after starting or changing dose, and a change in creatinine can have more than one explanation. The clinician should decide whether a medicine needs adjusting, whether monitoring is sufficient or whether an urgent assessment is required.
Recent illness, vomiting, diarrhoea or reduced fluid intake also matter. The NHS explanation of acute kidney injury describes dehydration, infection and some medicines among possible causes. Drinking extra water is not a substitute for reviewing an abnormal result, particularly if you have heart failure, fluid restrictions or feel unwell.
For repeat testing, follow the preparation agreed for your panel. NICE advises adults not to eat meat in the 12 hours before a creatinine-based eGFR test. That is not the same as a blanket instruction to fast from all food and drink. Other tests taken at the same appointment may have separate requirements, so the instructions should be clear before you attend.
When a kidney result needs urgent attention
Some kidney problems cause few symptoms. A screening report still needs review even if you feel normal. When symptoms are present, their severity and timing help determine how quickly you need care.
The NHS advises an urgent GP appointment or NHS 111 help if you think you have symptoms of acute kidney injury. These can include passing much less urine than usual, vomiting, swollen legs, confusion, unusual sleepiness or breathlessness. A new abnormal kidney result with significant illness should not wait for a routine executive-screening appointment.
If you are severely unwell, seek emergency help. The immediate priority is assessment and treatment, rather than arranging another private screening panel. The Wellness enquiry route is for organising appropriate planned care, not a replacement for emergency services.
How a kidney review fits an executive health assessment
Kidney health connects with blood pressure, diabetes and cardiovascular risk. That makes it a useful part of a clinically selected executive assessment, rather than an isolated longevity score. The doctor can bring together blood results, urine findings, medical history and medicines to identify the next decision that matters.
Our existing corporate executive screening guide describes the wider programme. A kidney-marker review addresses a more specific need: understanding a result that has already been measured and deciding what follows. A comprehensive report is most useful when the review is as carefully organised as the testing.
A specialist referral is not necessary for every mildly reduced result. It may be appropriate when there are particular urine findings, a significant decline, suspected inherited disease or other concerning features. NICE sets out referral criteria and the use of validated kidney-failure risk assessment in relevant adults. Your doctor should explain the reason for any referral rather than treating a laboratory flag as the whole decision.
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What you leave the review knowing
The outcome should be an explanation you can use: whether the result is likely to represent a persistent change, what remains uncertain, and whether another test or assessment is needed. Any follow-up should have a defined purpose and a clinician responsible for considering the result.
Previous laboratory reports are valuable because the trend can be more informative than one measurement. Bring the original reports with dates, units and reference ranges, together with your current medication and supplement list. If tests were taken during an illness, after a treatment change or under unusual circumstances, that information helps the doctor interpret them.
The Wellness can help organise a doctor-led review and an appropriate next step. The scope, fee and arrangements for any additional testing or specialist consultation should be confirmed before booking. The value is a considered medical plan, with testing selected for a reason and continuity after the report arrives.
Frequently asked questions
Does a single low eGFR mean I have chronic kidney disease?
No. Chronic kidney disease requires evidence of a persistent abnormality or other established markers of kidney damage. A newly low result still needs timely medical review. NICE recommends repeating an eGFR below 60 within two weeks in an adult not previously tested, with earlier action when clinically needed.
Is eGFR of 60 to 89 always abnormal?
Not necessarily. This range alone does not diagnose chronic kidney disease. Previous results, urine ACR, other markers of kidney damage and the clinical context determine its significance. Estimates become less accurate at higher filtration levels.
Why might I need a urine ACR if I already had blood tests?
Urine ACR looks for albumin leakage, which adds information about kidney damage that eGFR alone cannot provide. NICE recommends it in relevant groups including adults with diabetes and adults with eGFR below 60. The doctor decides whether it is appropriate and whether confirmation is needed.
Can muscle mass affect creatinine and eGFR?
Yes. NICE advises caution with creatinine-based estimates in people with extremes of muscle mass and other circumstances affecting creatinine. A doctor can interpret the result alongside your history, previous tests and any need for a different assessment.
Should I stop my medicines before repeating a kidney blood test?
Do not stop prescribed medicines without medical advice. Give the reviewing doctor a full list, including over-the-counter painkillers and supplements. They can decide whether a treatment change, monitoring or another assessment is needed.
Can The Wellness review kidney results from another provider?
You can request a doctor-led review and provide your original reports, dates, units and medical history. The team confirms the appointment scope and fee before booking. Additional blood or urine tests may be recommended when the existing information does not answer the clinical question.
Contact The Wellness about your kidney blood test results
Evidence and further reading
- NICE NG203: chronic kidney disease assessment and management.
- NHS: diagnosing chronic kidney disease.
- NHS: acute kidney injury.
This article provides general information for adults. It does not diagnose a condition or replace an individual medical assessment.