eGFR and creatinine are two of the most important blood test results used to assess kidney function. They are often included in a wider kidney blood test or U&E blood test, alongside urea and electrolytes such as sodium and potassium.
Creatinine is a waste product made by your muscles. Your kidneys remove it from the blood. The eGFR, or estimated glomerular filtration rate, uses creatinine together with factors such as age and sex to estimate how well your kidneys are filtering blood.
These results are useful, but they can also be misunderstood. A high creatinine does not always mean permanent kidney disease. A mildly reduced eGFR does not always mean your kidneys are failing. A single abnormal result may be caused by dehydration, medicines, recent illness, muscle mass, supplements or a temporary kidney injury. On the other hand, a persistently low eGFR, a falling trend, protein in the urine or abnormal results with symptoms should not be ignored.
This guide explains what creatinine and eGFR mean, how to read the results, what can cause abnormal kidney blood tests, when to seek urgent advice, and what usually happens next.
Important: This article is for general information only and should not replace medical advice. Kidney blood test results must be interpreted alongside your symptoms, medicines, blood pressure, urine results, previous results and medical history. Always discuss abnormal results with your GP, kidney specialist or the clinician who arranged the test.
What is creatinine?
Creatinine is a waste product made when your muscles use creatine for energy. Creatinine is produced fairly steadily each day, then filtered out of the blood by the kidneys and removed in urine.
Because the kidneys remove creatinine, a higher creatinine level can suggest that the kidneys are not filtering as well as expected. However, creatinine is not a perfect kidney test by itself. It is affected by muscle mass, age, sex, hydration, diet, some medicines and supplements.
For example, a muscular person may naturally have a higher creatinine than a smaller, older or frail person. Someone with very low muscle mass may have a creatinine result that looks “normal” even when kidney function is reduced. This is why eGFR is usually reported as well.
The NHS explains that the main blood test for kidney disease measures creatinine, and the result is used with factors such as age and sex to calculate estimated kidney filtration. NHS: Chronic kidney disease diagnosis.
What is eGFR?
eGFR stands for estimated glomerular filtration rate. It is a calculation that estimates how much blood your kidneys filter each minute. It is calculated from your creatinine result, age and sex. Some equations may also use other markers such as cystatin C in specialist settings, but routine eGFR is usually creatinine-based.
Laboratories usually report eGFR whenever creatinine is measured. NICE recommends that when serum creatinine is requested, laboratories should report creatinine-based eGFR as well. NICE: Chronic kidney disease assessment and management.
eGFR is reported as mL/min/1.73m². This can look technical, but in simple terms it estimates your kidney filtering capacity adjusted to a standard body surface area.
In general:
- higher eGFR means better estimated kidney filtration;
- lower eGFR means reduced estimated kidney filtration;
- falling eGFR over time may suggest worsening kidney function;
- stable eGFR may suggest a long-term baseline, depending on the level.
Lab Tests Online UK describes eGFR as a calculation using creatinine to estimate how well the kidneys are filtering waste from the blood. Lab Tests Online UK: eGFR.
Why are eGFR and creatinine checked?
Creatinine and eGFR are checked for many reasons. Sometimes they are part of a routine blood test. Sometimes they are requested because a clinician is worried about kidney function, dehydration, medicine effects or a long-term condition.
Common reasons include:
- checking kidney function as part of a routine health review;
- monitoring high blood pressure or diabetes;
- checking for chronic kidney disease;
- checking kidney function before starting or changing certain medicines;
- monitoring medicines that can affect kidney function or potassium;
- checking kidney function during or after dehydration, vomiting, diarrhoea or severe illness;
- checking before surgery or scans using contrast dye;
- investigating abnormal urine tests, protein in urine or blood in urine;
- following up abnormal private blood test results.
These results are often interpreted alongside urine test results, blood pressure, diabetes tests, cholesterol results and other kidney markers such as urea and electrolytes.
Creatinine and eGFR: how they relate to each other
Creatinine and eGFR usually move in opposite directions:
- if creatinine rises, eGFR usually falls;
- if creatinine falls, eGFR usually rises.
This is because eGFR is calculated from creatinine. When creatinine builds up in the blood, it can mean the kidneys are filtering less well. But because creatinine is also influenced by muscle and other factors, eGFR is still an estimate, not a direct measurement.
A useful way to think about it is:
- creatinine is the measured waste product;
- eGFR is the estimated filtering rate calculated from that result.
What is a normal creatinine result?
Creatinine reference ranges vary by laboratory, sex, age and muscle mass. Men often have higher creatinine than women because they tend to have more muscle mass. Athletes and bodybuilders may also have higher baseline creatinine.
A typical adult reference range may be roughly:
| Group | Typical creatinine range | Important note |
|---|---|---|
| Adult women | About 45–90 micromol/L | Ranges vary by laboratory and body size. |
| Adult men | About 60–110 micromol/L | Higher muscle mass can increase creatinine. |
These are broad examples only. Always use the range printed on your own report. A creatinine of 100 micromol/L may be acceptable for one person but more concerning for another, depending on age, sex, muscle mass and previous results.
What is a normal eGFR result?
An eGFR of 90 or above is often considered normal kidney filtration, as long as there are no other signs of kidney disease. An eGFR between 60 and 89 may be normal for some people, especially with age, if there is no protein in the urine or other evidence of kidney damage.
Kidney Research UK explains that a normal eGFR is greater than 90, but values as low as 60 may be considered normal if there is no other evidence of kidney disease. Kidney Research UK: Understanding kidney blood test results.
| eGFR result | Broad meaning |
|---|---|
| 90 or above | Usually normal kidney filtration, unless there are other signs of kidney disease such as protein in urine. |
| 60–89 | Mildly reduced. May be normal for age if urine tests and other markers are normal. |
| 45–59 | Mild to moderate reduction. Often needs repeat testing and urine ACR. |
| 30–44 | Moderate to severe reduction. Usually needs monitoring and risk reduction. |
| 15–29 | Severe reduction. Specialist kidney input may be needed depending on context. |
| Below 15 | Very severe reduction. Needs specialist assessment and planning. |
These stages are not the whole story. The amount of protein or albumin in the urine is also very important. The UK Kidney Association explains that CKD classification uses both eGFR and the amount of protein in urine, because together they help estimate severity and future risk. UK Kidney Association: CKD staging.
Does a low eGFR mean chronic kidney disease?
Not always. A low eGFR on one blood test does not automatically mean chronic kidney disease. It may be temporary, especially if you were dehydrated, unwell, taking certain medicines, or had a recent kidney stress.
Chronic kidney disease, or CKD, usually means kidney abnormalities have been present for at least three months. This may include a persistently reduced eGFR, protein in the urine, blood in the urine, structural kidney problems or other evidence of kidney damage.
For example:
- an eGFR of 55 during dehydration may improve after recovery;
- an eGFR of 55 that has been stable for years may represent a chronic baseline;
- an eGFR of 75 with significant protein in the urine may still suggest kidney disease;
- an eGFR of 65 with normal urine, normal blood pressure and no other evidence of kidney disease may not be CKD.
This is why a urine ACR test and repeat blood testing are often important.
What is urine ACR and why does it matter?
Urine ACR stands for albumin-to-creatinine ratio. It checks whether there is an increased amount of albumin, a type of protein, in the urine. Protein leaking into the urine can be an early sign of kidney damage.
Urine ACR matters because eGFR alone does not fully describe kidney risk. Someone with a mildly reduced eGFR and no protein in the urine may have a lower risk than someone with a similar eGFR and a high ACR.
Kidney disease staging often uses both:
- G stage — based on eGFR;
- A stage — based on urine albumin or ACR.
This is particularly important for people with diabetes, high blood pressure, cardiovascular disease or a family history of kidney disease.
High creatinine result explained
A high creatinine result means there is more creatinine in your blood than expected. This can happen if the kidneys are filtering less well, but it can also be influenced by muscle mass, dehydration, diet, supplements and medicines.
Common causes of high creatinine
Possible causes include:
- dehydration;
- acute kidney injury;
- chronic kidney disease;
- high muscle mass;
- recent intense exercise or muscle injury;
- creatine supplements;
- large recent meat intake before the test;
- urinary blockage, such as severe prostate enlargement or kidney stones;
- some medicines, including NSAIDs and certain antibiotics;
- heart failure or reduced blood flow to the kidneys;
- severe infection or major illness.
The most important question is whether the creatinine is newly raised, rapidly rising or stable over time. A sudden rise can suggest acute kidney injury. A stable mild rise may reflect long-term kidney function, muscle mass or another chronic factor.
Low eGFR result explained
A low eGFR means estimated kidney filtration is lower than expected. The lower the eGFR, the more reduced the estimated kidney function. But interpretation depends heavily on context.
Common causes of low eGFR
Possible causes include:
- dehydration or reduced blood flow to the kidneys;
- acute kidney injury;
- chronic kidney disease;
- diabetes-related kidney disease;
- high blood pressure-related kidney disease;
- kidney inflammation, such as glomerulonephritis;
- urinary blockage;
- heart failure;
- medicine effects;
- older age, with gradual decline in filtration over time;
- limitations of the eGFR calculation due to muscle mass or body size.
A low eGFR should usually be compared with previous results. If there is no previous result, your clinician may repeat it and arrange urine testing.
Can dehydration affect creatinine and eGFR?
Yes. Dehydration can raise creatinine and lower eGFR temporarily. This may happen after vomiting, diarrhoea, fever, heat exposure, poor fluid intake, heavy sweating or taking diuretics.
In dehydration, the kidneys may receive less blood flow, and waste products can become more concentrated in the blood. Once hydration and illness improve, creatinine and eGFR may improve too.
However, dehydration can also trigger acute kidney injury, especially in older adults, people with chronic kidney disease, diabetes, heart failure, or those taking medicines that affect kidney blood flow. If you have severe dehydration, very reduced urine output, confusion, fainting or persistent vomiting, seek urgent medical advice.
See also Dehydration Symptoms in Adults and Children.
Medicines that can affect creatinine and eGFR
Some medicines can affect kidney function or change creatinine levels. Sometimes this is expected and monitored. Sometimes it means the medicine needs reviewing, especially during illness or dehydration.
Medicines that may affect kidney blood tests include:
- ACE inhibitors, such as ramipril, lisinopril or enalapril;
- ARBs, such as losartan, candesartan or valsartan;
- diuretics, such as furosemide, bendroflumethiazide or indapamide;
- spironolactone, eplerenone or amiloride;
- NSAIDs, such as ibuprofen, naproxen and diclofenac;
- trimethoprim and some other antibiotics;
- lithium;
- some chemotherapy, immune and antiviral medicines;
- contrast dye used for some scans;
- creatine supplements, which may affect creatinine interpretation.
Do not stop prescribed medicines without medical advice unless you have been given specific sick-day guidance or urgent instructions. Many kidney-protective medicines, such as ACE inhibitors and ARBs, can cause a small expected change in creatinine when started, but they may still be beneficial long term.
ACE inhibitors, ARBs and creatinine changes
ACE inhibitors and ARBs are commonly used for high blood pressure, heart disease, diabetes and kidney protection. They can cause a small rise in creatinine after starting or increasing the dose. This is why kidney function and potassium are often checked before and after changes.
A small, stable change may be acceptable. A large rise, worsening kidney function or high potassium may need review. Your clinician will interpret the change based on your baseline result, blood pressure, potassium, hydration and other conditions.
If your potassium is also abnormal, see U&E Blood Test Results Explained.
Can diet, protein or creatine supplements affect creatinine?
Yes. Creatinine can be affected by recent meat intake, high-protein diets, creatine supplements and muscle mass.
For example:
- eating a large meat meal before a blood test may slightly increase creatinine;
- creatine supplements can raise creatinine or make interpretation harder;
- bodybuilders may have higher creatinine because of muscle mass and supplements;
- people with very low muscle mass may have deceptively low creatinine.
If you take creatine or have recently changed your diet or training, tell the clinician reviewing your results. In some cases, repeat testing or a cystatin C-based estimate may be considered.
Can exercise affect creatinine?
Yes. Recent intense exercise, heavy weight training, endurance events or muscle injury can raise creatinine. Severe muscle breakdown, called rhabdomyolysis, can cause dangerous kidney injury and usually raises another blood marker called creatine kinase, or CK.
Seek urgent medical advice if you have severe muscle pain, weakness, swelling or dark cola-coloured urine after intense exercise, injury, heat illness or drug use.
Can eGFR be inaccurate?
Yes. eGFR is an estimate. It is very useful for routine kidney assessment, but it has limitations.
eGFR may be less accurate in people who:
- are very muscular;
- have very low muscle mass or frailty;
- are pregnant;
- have had an amputation;
- have severe obesity or very low body weight;
- are acutely unwell;
- have rapidly changing kidney function;
- take creatine supplements;
- have unusual diets or recent heavy meat intake.
In these situations, doctors may interpret eGFR cautiously. Specialist tests, cystatin C, measured GFR or creatinine clearance may occasionally be used when more accuracy is needed, for example before certain treatments.
What is cystatin C?
Cystatin C is another blood marker that can be used to estimate kidney function. It is less dependent on muscle mass than creatinine, although it has its own limitations. It is not always used routinely, but it may help in selected cases where creatinine-based eGFR is uncertain.
Your clinician may consider cystatin C if your creatinine result does not fit the clinical picture, or if a more accurate kidney function estimate is important for diagnosis or medication dosing.
What is acute kidney injury?
Acute kidney injury, often shortened to AKI, means kidney function has suddenly worsened over hours or days. It is often detected by a rise in creatinine or a drop in urine output.
AKI can happen with:
- dehydration;
- severe infection or sepsis;
- major surgery or severe illness;
- heart failure or low blood pressure;
- urinary blockage;
- kidney inflammation;
- medicine effects, especially during dehydration or illness.
AKI can be reversible, especially when treated early, but it can also be serious. A sudden rise in creatinine should be reviewed promptly, especially if you are unwell, not passing much urine, dehydrated or taking kidney-affecting medicines.
What is chronic kidney disease?
Chronic kidney disease, or CKD, means there is long-term abnormal kidney structure or function. CKD is often silent in the early stages, which is why blood and urine tests are important in people at risk.
Common risk factors include:
- high blood pressure;
- diabetes;
- cardiovascular disease;
- family history of kidney disease;
- recurrent kidney stones or urinary obstruction;
- autoimmune disease;
- long-term use of medicines that can affect the kidneys;
- previous acute kidney injury;
- older age.
NHS England notes that CKD is classified into stages based on eGFR and albuminuria levels, and that early CKD often has no symptoms. NHS England: Kidney disease.
CKD stages by eGFR
CKD staging is usually based on eGFR and urine ACR. The eGFR stages are often described as G1 to G5.
| Stage | eGFR | Broad meaning |
|---|---|---|
| G1 | 90 or above | Normal or high eGFR. CKD only if other evidence of kidney damage is present. |
| G2 | 60–89 | Mildly reduced eGFR. CKD only if other evidence of kidney damage is present. |
| G3a | 45–59 | Mild to moderate reduction. |
| G3b | 30–44 | Moderate to severe reduction. |
| G4 | 15–29 | Severe reduction. |
| G5 | Below 15 | Kidney failure range. Specialist care is usually needed. |
G1 and G2 do not usually count as CKD unless there is other evidence of kidney damage, such as albumin in the urine, blood in the urine of kidney origin, structural abnormalities or a known kidney condition.
Symptoms of reduced kidney function
Early kidney disease often causes no symptoms. Many people only find out through blood or urine tests.
When kidney function is more reduced, possible symptoms can include:
- tiredness or weakness;
- swollen ankles, legs or feet;
- puffiness around the eyes;
- shortness of breath;
- needing to pass urine more often at night;
- reduced urine output in acute illness;
- itching;
- nausea or loss of appetite;
- muscle cramps;
- high blood pressure;
- confusion or drowsiness in severe cases.
These symptoms can have many causes. For example, swollen legs may be due to veins, heart, medicines, kidneys or other causes. See Swollen Legs and Ankles: Veins, Heart, Kidneys, Medicines or Something Else?.
When are eGFR and creatinine results urgent?
Many abnormal kidney blood results can be reviewed routinely, especially if the change is mild and you feel well. But some situations need urgent medical advice.
Seek urgent medical help if abnormal kidney results come with:
- very reduced urine output or inability to pass urine;
- severe dehydration, persistent vomiting or severe diarrhoea;
- confusion, collapse, severe weakness or drowsiness;
- severe shortness of breath or chest pain;
- rapidly worsening swelling of the legs, face or abdomen;
- severe back or loin pain with fever;
- blood in urine with clots or inability to pass urine;
- known kidney disease and a sudden worsening in results;
- high potassium or other dangerous electrolyte changes;
- a result reported as critical or urgent by the laboratory or clinician.
If you are acutely unwell and your creatinine has suddenly risen or eGFR has suddenly fallen, do not wait for a routine appointment.
What happens after abnormal creatinine or eGFR?
The next step depends on the result, symptoms, previous results and risk factors. Your clinician may recommend:
- repeating creatinine and eGFR;
- checking urea and electrolytes, especially potassium;
- checking urine ACR for albumin or protein;
- checking urine dipstick for blood, protein, glucose or infection;
- checking blood pressure;
- reviewing medicines, especially NSAIDs, ACE inhibitors, ARBs, diuretics, lithium and antibiotics;
- checking HbA1c if diabetes is possible or already known;
- checking cholesterol and cardiovascular risk;
- checking full blood count, ferritin, calcium, phosphate or parathyroid hormone in some cases;
- arranging kidney or bladder ultrasound if obstruction or structural disease is suspected;
- referring to a kidney specialist if results are severe, progressive or complicated.
If your abnormal result came from a private blood test, do not assume it will automatically reach your GP. See What to Do After Abnormal Private Blood Test Results.
Should creatinine and eGFR be repeated?
Often, yes. Repeating the test helps show whether the abnormality is temporary or persistent. This is especially useful if you were dehydrated, recently unwell, had changed medicines, used NSAIDs, exercised heavily, or had no previous results for comparison.
A repeat result may show:
- kidney function has returned to your usual baseline;
- kidney function is stable but mildly reduced;
- kidney function is continuing to worsen;
- the first result may have been affected by temporary factors.
Your clinician will decide how soon to repeat the test. A mild abnormality in someone who feels well may be repeated routinely. A sudden or severe abnormality may need same-day or urgent follow-up.
What is a significant change in creatinine or eGFR?
Small changes can happen because of hydration, laboratory variation and normal biological fluctuation. Larger changes are more important.
A change may be more concerning if:
- creatinine has risen quickly compared with previous results;
- eGFR has fallen by a large amount over days or weeks;
- eGFR is falling steadily over months or years;
- eGFR has dropped below 60 and remains there;
- urine ACR is raised;
- there is blood in urine;
- potassium is high;
- you have symptoms or are acutely unwell.
Trends matter. A single eGFR of 58 may be less concerning if it has been stable for years and urine ACR is normal. A drop from 95 to 58 over a short time is more concerning and needs review.
eGFR and high blood pressure
High blood pressure can damage the kidneys over time, and kidney disease can also raise blood pressure. This is why blood pressure and kidney function are closely linked.
If eGFR is reduced, blood pressure control is one of the most important ways to reduce the risk of further kidney damage and cardiovascular disease. Many people with CKD are treated with ACE inhibitors or ARBs, especially if there is protein in the urine.
For more detail, see High Blood Pressure: Symptoms, Causes and Treatment and Home Blood Pressure Monitoring.
eGFR and diabetes
Diabetes is one of the most common causes of chronic kidney disease. High blood sugar can damage the small filtering units in the kidneys over time. Kidney damage from diabetes may first show as albumin in the urine, even before eGFR falls.
If you have diabetes, monitoring often includes:
- eGFR and creatinine;
- urine ACR;
- blood pressure;
- HbA1c;
- cholesterol and cardiovascular risk.
See HbA1c and Blood Sugar Results Explained for more on diabetes-related blood test results.
eGFR before scans, surgery or procedures
Kidney function may be checked before certain scans, operations or procedures. This is especially important when contrast dye may be used, or when medicines need dose adjustment based on kidney function.
For example, eGFR may be checked before some CT or MRI scans with contrast. If eGFR is reduced, the imaging team may adjust the plan, use a different scan, give hydration advice or avoid certain contrast agents depending on the situation.
Related guides include CT Scan: What It Shows and How It Differs from MRI, MRI Scan: What It Shows and Ultrasound vs CT vs MRI.
eGFR and medicine dosing
Some medicines are cleared by the kidneys, so doses may need adjusting when eGFR is reduced. This is particularly important for some antibiotics, diabetes medicines, blood thinners, pain medicines and specialist drugs.
Do not adjust doses yourself. If your eGFR has changed, ask the clinician or pharmacist whether any medicines need review.
Creatinine, eGFR and other blood results
Kidney blood tests are rarely interpreted alone. Other results can change the meaning.
| Pattern | Possible meaning |
|---|---|
| High creatinine + low eGFR | Reduced estimated kidney filtration. Needs context, trend and urine testing. |
| High creatinine + high urea | May suggest dehydration, reduced kidney function, acute kidney injury or reduced blood flow to kidneys. |
| Low eGFR + raised urine ACR | More suggestive of kidney disease and higher risk than eGFR alone. |
| Low eGFR + high potassium | Potentially important. Medicines, kidney function and urgency need review. |
| Low eGFR + anaemia | CKD can contribute, but other causes of anaemia should also be considered. |
| Low eGFR + abnormal platelets or liver tests | May suggest a broader illness, liver disease, inflammation, medication effect or systemic condition. |
Useful related guides include Platelet Count Results Explained and ALT, AST, ALP and GGT Liver Results Explained.
Can kidney function improve?
Sometimes, yes. If abnormal results are due to dehydration, acute illness, urinary blockage, medicine effects or temporary kidney stress, kidney function may improve when the cause is treated.
Chronic kidney disease may not fully reverse, but progression can often be slowed. Important steps may include:
- good blood pressure control;
- good diabetes control if relevant;
- reducing urine protein with appropriate medicines;
- stopping smoking;
- reviewing kidney-affecting medicines;
- avoiding unnecessary NSAIDs;
- maintaining a healthy weight;
- managing cholesterol and cardiovascular risk;
- regular monitoring of eGFR, ACR and blood pressure.
The aim is not only to protect the kidneys, but also to reduce the risk of heart attack and stroke, because kidney disease and cardiovascular risk are closely linked.
Should you drink more water to improve eGFR?
Being normally hydrated helps blood tests reflect your usual kidney function. If you were dehydrated, drinking fluids and recovering from illness may improve creatinine and eGFR.
However, overdrinking water is not a treatment for chronic kidney disease and can be harmful in some people, especially those with heart failure, advanced kidney disease or low sodium. Aim for sensible hydration unless your clinician has given you specific fluid advice.
Should you avoid protein if eGFR is low?
Do not start a very low-protein diet without medical advice. Protein needs depend on your kidney function, nutritional status, age, weight, diabetes status and other health conditions.
Very high-protein diets and bodybuilding supplements may make kidney blood tests harder to interpret and may not be appropriate for some people with kidney disease. But overly restrictive diets can cause malnutrition. If you have CKD, ask your GP, kidney team or renal dietitian before making major dietary changes.
How to read your eGFR and creatinine results sensibly
When you receive your results, avoid focusing on one number in isolation. Ask:
- Is creatinine high, low or normal for me? Consider age, sex and muscle mass.
- What is the eGFR? Is it above 90, 60–89, below 60, or much lower?
- Is this result new? Previous results are very useful.
- Is it changing quickly? A sudden change is more concerning than a stable long-term result.
- Was I dehydrated or unwell? Recent illness can temporarily affect kidney tests.
- Are medicines involved? NSAIDs, diuretics, ACE inhibitors, ARBs, lithium and antibiotics can matter.
- Is urine ACR abnormal? Protein in urine changes kidney risk.
- Is potassium high? This can affect urgency.
- Do I have symptoms? Reduced urine, swelling, breathlessness, confusion or severe illness need prompt attention.
A good interpretation looks at the pattern, trend and whole person, not just the highlighted number.
FAQ: eGFR and creatinine results
What is creatinine?
Creatinine is a waste product made by muscles. The kidneys remove it from the blood. A high creatinine result can suggest reduced kidney filtration, but it can also be affected by muscle mass, hydration, diet, exercise, medicines and supplements.
What is eGFR?
eGFR stands for estimated glomerular filtration rate. It estimates how well your kidneys are filtering blood, using your creatinine result together with factors such as age and sex.
Is eGFR more important than creatinine?
Both matter. Creatinine is the measured result, while eGFR estimates kidney filtration from creatinine. eGFR is often easier to interpret for kidney function, but creatinine trends and context are also important.
What is a normal eGFR?
An eGFR of 90 or above is usually considered normal if there are no other signs of kidney disease. An eGFR between 60 and 89 may be normal for some people, especially with age, if urine tests and other markers are normal.
What eGFR means kidney disease?
An eGFR below 60 that persists for at least three months may suggest chronic kidney disease. However, CKD can also be present with higher eGFR if there is protein in the urine or other evidence of kidney damage.
Does one low eGFR mean I have CKD?
No. One low eGFR does not automatically mean chronic kidney disease. It may be temporary due to dehydration, illness, medicines or acute kidney injury. Repeat testing and urine ACR are often needed.
Why is my creatinine high but I feel well?
Creatinine can be mildly high without symptoms. Possible reasons include reduced kidney function, dehydration, high muscle mass, creatine supplements, recent intense exercise, medicines or a stable long-term baseline.
Can dehydration lower eGFR?
Yes. Dehydration can raise creatinine and lower eGFR temporarily. Severe dehydration can also trigger acute kidney injury, especially in people with risk factors.
Can creatine supplements raise creatinine?
Yes. Creatine supplements can raise creatinine or make kidney results harder to interpret. Tell your clinician if you use creatine, bodybuilding supplements or a high-protein diet.
Can exercise raise creatinine?
Yes. Intense exercise or muscle injury can raise creatinine. Severe muscle breakdown can cause kidney injury and may cause dark urine, muscle pain and weakness, which need urgent medical advice.
Can medicines affect eGFR?
Yes. NSAIDs, diuretics, ACE inhibitors, ARBs, lithium, trimethoprim and some other medicines can affect kidney blood tests. Do not stop prescribed medicines without advice unless you have been given specific urgent instructions.
What is urine ACR?
Urine ACR is the albumin-to-creatinine ratio. It checks for albumin, a type of protein, in the urine. A raised ACR can be an early sign of kidney damage and is important for CKD risk assessment.
Can eGFR improve?
Yes, if the reduction was due to a temporary cause such as dehydration, illness, medicine effects or urinary blockage. Chronic kidney disease may not fully reverse, but progression can often be slowed with good management.
What eGFR needs a kidney specialist?
This depends on the situation. Specialist referral may be considered for severe reduction, rapidly falling eGFR, significant urine protein, blood in urine of kidney origin, difficult blood pressure, inherited kidney disease, or complicated cases.
Is eGFR accurate in older people?
eGFR is useful in older adults, but it must be interpreted with overall health, muscle mass, urine ACR and trends. Mildly reduced eGFR can be common with age and does not always mean serious kidney disease.
Is eGFR accurate in bodybuilders?
It may be less accurate because creatinine is affected by muscle mass and creatine supplements. A muscular person may have higher creatinine and lower calculated eGFR without the same meaning as in someone with average muscle mass.
Should I drink lots of water before a kidney blood test?
You should be normally hydrated, but do not overdrink. Excessive water intake can be harmful in some people and may affect sodium levels. Follow your clinician’s advice if you have heart failure, kidney disease or fluid restrictions.
Can a normal creatinine hide kidney disease?
Sometimes. People with low muscle mass may have a creatinine that looks normal despite reduced kidney function. Urine ACR, eGFR trends and clinical context help give a fuller picture.
What should I do if my private blood test shows low eGFR or high creatinine?
Contact the provider or a qualified clinician for interpretation. Seek urgent advice if you are unwell, passing very little urine, dehydrated, breathless, confused, have severe pain, high potassium or a result reported as critical.
