Lab results explained
High creatinine: what it means
Last checked against the sources below on · How we write health pages
Short answer: High creatinine usually means your kidneys are filtering waste more slowly than expected. Typical upper limits are about 1.35 mg/dL (119 µmol/L) for men and 1.04 mg/dL (92 µmol/L) for women. Dehydration, a meat-heavy meal, hard exercise and some medicines can raise it too, so doctors look at eGFR and repeat tests.
Have your report? See what every number means.
Free, no sign-up. Your report is read on this device and never uploaded.
Typical adult range
Your lab may print a slightly different range. Use the one on your report when there is one.
| Test | Men | Women |
|---|---|---|
| Creatinine | 0.74–1.35 mg/dL65.4–119 µmol/L | 0.59–1.04 mg/dL52.2–91.9 µmol/L |
| eGFR (kidney filtering) | Stage G5 (kidney failure range): under 15 mL/min/1.73m² Stage G4 (severely decreased): 15–30 mL/min/1.73m² Stage G3b (moderately to severely decreased): 30–45 mL/min/1.73m² Stage G3a (mildly to moderately decreased): 45–60 mL/min/1.73m² Stage G2 (mildly decreased): 60–90 mL/min/1.73m² Normal (G1): 90 or more mL/min/1.73m² | |
| Blood urea | 15–45 mg/dL2.5–7.49 mmol/L | |
What creatinine measures
Creatinine is a waste product made when your muscles work. Healthy kidneys filter it out of the blood and pass it into urine, so the level stays fairly steady. When filtering slows, creatinine builds up. Labs use your creatinine, age and sex to work out the eGFR, an estimate of how much blood your kidneys clean each minute. An eGFR of 90 or more is normal, and under 60 for three months or longer is one sign of chronic kidney disease. To convert, multiply mg/dL by 88.4 to get µmol/L, the unit used in the UK and many other countries.
Common causes of a high reading
A single high creatinine does not always mean kidney disease. Short-term causes are common, and some people simply carry more muscle, which raises creatinine without any kidney problem. Longer-term rises are most often linked to diabetes and high blood pressure, the two leading causes of kidney disease worldwide. Your doctor will think about your recent health, your medicines and your past results before deciding what the number means for you.
- Dehydration, vomiting or diarrhoea
- A large meat meal or creatine supplements before the test
- Very hard exercise in the day or two before
- Medicines such as NSAID painkillers, some blood pressure drugs and some antibiotics
- Long-standing diabetes or high blood pressure
- A blocked urine flow, for example from an enlarged prostate or kidney stones
Patterns doctors look at
The trend matters more than one result. A creatinine that jumps quickly over days points to a sudden kidney injury, which needs prompt care. A slow rise over months or years suggests chronic kidney disease. Doctors also look at urea (or BUN): a raised urea with only a small rise in creatinine often fits dehydration. A urine test for protein (the albumin to creatinine ratio, or ACR) shows whether the kidneys are leaking protein, which is an early sign of damage even when eGFR still looks fine.
What usually happens next
If the rise is mild and you feel well, the usual next step is a repeat blood test in a few days to a few weeks, after drinking normally and avoiding heavy exercise and big meat meals. Your doctor may check a urine test, blood pressure, blood sugar and your medicine list. If the result stays high, they may order a kidney ultrasound or refer you to a kidney specialist (nephrologist). Many people with mildly reduced kidney function stay stable for years with good blood pressure and sugar control.
When to get help the same day
Get same-day medical care if your creatinine has risen sharply since your last test, your eGFR is under 15, or you are passing very little urine. A creatinine of 10 mg/dL (884 µmol/L) or higher is a critical result. Call your local emergency number if you have trouble breathing, chest pain, confusion, severe drowsiness or a seizure.
Questions to ask your doctor
- Is this a one-off rise, or has my creatinine been creeping up over time?
- What is my eGFR, and what stage of kidney function does it suggest?
- Should I repeat the test, and how should I prepare for it?
- Could any of my medicines or supplements be affecting my kidneys?
- Do I need a urine albumin test or a kidney ultrasound?
Check your own results
Paste your report, drop the lab's PDF or type the values. Each result is compared with typical ranges and explained, with questions for your doctor.
- Read on your device, never uploaded
- No health data on our servers
- Explains results, doesn't diagnose
Educational only, not medical advice or a diagnosis. Reference ranges differ between labs; your doctor interprets results with your history. Results are only kept if you press Save, and then only in this browser.
More kidney tests (2)
Leave eGFR empty to have it calculated from creatinine (add your age and sex).
Enter a value above to see what it means.
Frequently asked questions
Can drinking more water lower creatinine?
If your creatinine is high because you were dehydrated, drinking normally again usually brings it back down. Water does not repair damaged kidneys, and people with advanced kidney disease or heart failure may be told to limit fluids, so follow your doctor's advice on how much to drink.
Is a creatinine of 1.5 mg/dL dangerous?
It is above the usual range and worth following up, but what it means depends on your age, sex, muscle mass and eGFR. For a muscular young man it may be close to normal; for an older woman it may reflect a larger drop in kidney function. A repeat test helps.
Does high creatinine always mean kidney disease?
No. Dehydration, heavy exercise, a big meat meal, creatine supplements and some medicines can all raise it for a short time. Chronic kidney disease is only diagnosed when eGFR stays low or there are other signs of kidney damage for at least three months.
What is the difference between creatinine and eGFR?
Creatinine is the raw blood level. eGFR is a calculation that uses creatinine, age and sex to estimate how well the kidneys filter. A higher creatinine gives a lower eGFR. Doctors use eGFR to stage kidney function because it is easier to compare between people.
Sources
- MedlinePlus: Creatinine test
- NIDDK: Chronic kidney disease tests and diagnosis
- NHS: Chronic kidney disease
This page explains what results usually mean. It isn't a diagnosis or medical advice; your doctor interprets results with your symptoms, history and medicines. Medical disclaimer
Read on your device
Your report is read by your own browser. It is never uploaded.
No health data on our servers
We don't have a database of results. Saved history stays in this browser.
Check it yourself
Load the page, turn off Wi-Fi, paste your results: it still works.
Explains, doesn't diagnose
Plain-English meaning and questions for your doctor. Not medical advice.
Feeling very unwell? Call your local emergency number now.How we handle health dataMedical disclaimer