High Creatinine: What Does It Mean for Your Kidneys?
Updated Aug 2026 · Reading time: 4 minutes
The short answer:A mildly high creatinine (roughly 105–130 µmol/L) is most often dehydration, muscle mass, or a recent hard workout — not kidney disease. The standard next step: drink water normally for a few days, repeat the test in 1–2 weeks, and if it stays high ask your doctor about an eGFR and a urine test. See a doctor promptly if a clearly high level comes with swelling, high blood pressure, or a big drop in how much you urinate.
What creatinine actually is
Creatinine is a waste product your muscles produce constantly. Healthy kidneys filter it out of your blood into urine. When the blood level creeps up, it can mean the kidneys are filtering a bit slower — or it can mean something much more ordinary.
Where your number sits
🟢 Normal: roughly 59–104 umol/L (varies by lab, age, sex, and muscle mass)Men and people with more muscle naturally run higher. Always read your own report's reference range.
🟡 Mildly high (105–130 umol/L):The most common zone people land in — and the most commonly misread. Often it's not kidney disease at all.
🔴 Clearly high (130+ umol/L):Worth a prompt doctor visit. They'll repeat the test and usually check eGFR, urine protein, and blood pressure.
Five everyday reasons creatinine runs high
- Dehydration. The #1 cause of a mildly high reading. Less water in = less filtering = higher blood level. Many people retest normal after drinking properly.
- Muscle mass. Muscular people and heavy exercisers naturally sit at the top of (or above) the range.
- Heavy exercise before the draw. Intense workouts temporarily raise creatinine.
- High protein intake. Big meat or supplement intake can nudge it up.
- Medications. Some blood pressure drugs and NSAIDs (ibuprofen) can raise creatinine — sometimes as a harmless "mechanical" effect.
Your follow-up plan
Repeat the test in 1–2 weeks. Before it, give your kidneys a fair reading: drink water normally for several days and skip intense workouts the day before the draw. If the level is still high, your doctor will look at the bigger picture — an eGFR (filtration estimate calculated from creatinine, age, and sex) and a urine test matter more than the creatinine number alone.
See your doctor sooner if you also have swelling in your legs or around your eyes, noticeably less urine, or blood pressure readings that are consistently high.
What to do next
Don't panic. Creatinine alone never tells the whole kidney story. Do: stay normally hydrated, retest in 1–2 weeks, and show your doctor the result together with the rest of your report — especially eGFR and urine findings if you have them.
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