Creatinine

High blood creatinine usually indicates reduced kidney function—from dehydration, acute injury, chronic kidney disease, muscle breakdown, or certain medicines. It warrants repeat tests (creatinine, eGFR, urine), review of medications and hydration, and possible imaging or specialist referral. Treatment targets the underlying cause, managing complications, and in severe cases dialysis. See a clinician promptly for evaluation and follow‑up.

Normal serum creatinine varies by sex, age and muscle mass. Typical adult ranges are about 0.74–1.35 mg/dL for men and 0.59–1.04 mg/dL for women (roughly 65–120 µmol/L and 52–92 µmol/L, respectively). Children and elderly often have lower values. Laboratory reference ranges differ, so interpret results with clinical context and your lab’s reported reference interval.

To lower creatinine: stay well hydrated, reduce high-protein/red-meat intake, limit salt and processed foods, avoid creatine supplements and NSAIDs. Control blood pressure and blood sugar, quit smoking, and maintain healthy weight with moderate exercise. Treat underlying kidney issues and review medications with your doctor to stop nephrotoxic drugs. See a specialist if creatinine remains elevated.

Low serum creatinine usually reflects reduced muscle mass, malnutrition, older age, pregnancy, or severe liver disease, and can sometimes stem from lab error. Low creatinine itself is rarely harmful, but it can overestimate kidney function (inflate eGFR). If unexpectedly low, clinicians will evaluate for muscle wasting, nutrition or liver problems, pregnancy, repeat testing and adjust interpretation accordingly.

High creatinine can indicate reduced kidney function and may be worrying depending on the cause and degree of rise. Causes include dehydration, muscle injury, medications, or chronic kidney disease. One isolated mild increase may be reversible; persistent or rising creatinine, low eGFR, symptoms, or abnormal urine tests are concerning and warrant prompt medical evaluation and treatment to prevent progression.

Early signs of kidney problems include changes in urination (less or more frequent, foamy, dark, bloody, or cloudy urine), swelling in the ankles, feet or face from fluid retention, persistent fatigue or weakness, loss of appetite, nausea, and unexplained shortness of breath. You may also notice high blood pressure and persistent back or flank pain. Seek medical evaluation if these symptoms appear.