Kidney Biomarker
Collection Type: Blood
Related System: Kidney
Serum creatinine measures the amount of creatinine a waste product of normal muscle metabolism circulating in the blood. It is filtered and excreted by the kidneys, so blood creatinine is a core marker of kidney filtration (glomerular) function. Elevated levels suggest reduced kidney function from acute kidney injury (AKI), chronic kidney disease (CKD), urinary obstruction, dehydration, or muscle breakdown; symptoms prompting testing include reduced urine output, swelling, fatigue, nausea, breathlessness, or flank pain. Results vary by age, sex, muscle mass and ethnicity: men and people with greater muscle mass normally have higher creatinine; older adults and those with low muscle mass typically have lower baseline values.
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Symptom CheckerMale: 0.74-1.35 mg/dL OR 65-119 μmol/L; Female: 0.59-1.04 mg/dL OR 52-92 μmol/L
Q: What happens if serum creatinine is high?
A: Elevated serum creatinine indicates reduced kidney filtration and may signal acute kidney injury or chronic kidney disease. Waste products and fluids can accumulate, causing fatigue, nausea, swelling, shortness of breath, decreased urine output, electrolyte imbalances, and uremia. High creatinine raises risk of hypertension and cardiovascular problems. Prompt evaluation, repeat testing, identifying the cause, and treatment (fluids, medications, dialysis if severe) is required.
Q: What is the normal serum creatinine?
A: Normal serum creatinine in adults is roughly 0.6–1.3 mg/dL, typically lower in women (about 0.6–1.1 mg/dL) and slightly higher in men (about 0.7–1.3 mg/dL). Children have lower values (≈0.3–0.7 mg/dL). Results vary with age, sex, muscle mass and laboratory methods. To convert mg/dL to µmol/L, multiply by 88.4 (0.6–1.3 mg/dL 53–115 µmol/L).
Q: What if serum creatinine is low?
A: Low serum creatinine commonly reflects reduced muscle mass, low protein intake, malnutrition, aging, pregnancy, or liver disease (reduced creatine production). It rarely indicates kidney disease by itself but can make eGFR appear falsely normal/high. If unexplained or accompanied by weakness, weight loss, swelling, or liver symptoms, seek evaluation—repeat testing, nutritional and muscle/liver assessment, or alternative kidney markers (e.g., cystatin C).
Q: What is a bad level of creatinine?
A: Creatinine levels vary by age, sex and muscle mass; normal serum creatinine is roughly 0.6–1.3 mg/dL. Persistently above the reference range suggests reduced kidney function. Values above about 1.5–2.0 mg/dL are generally concerning; levels ≥4 mg/dL usually indicate severe impairment or acute kidney injury and require urgent evaluation. Always interpret creatinine with eGFR and clinical context.
Q: How to cure high creatinine?
A: High creatinine reflects reduced kidney function; treatment focuses on treating the underlying cause and slowing damage. See a nephrologist; control blood pressure and diabetes; stop nephrotoxic drugs (NSAIDs, some antibiotics, contrast); stay appropriately hydrated; follow a kidney-friendly diet (lower protein, salt, potassium as advised); adjust medications; treat infections; and in advanced cases dialysis or transplant may be needed.
Q: Is high creatinine worrying?
A: High creatinine can be worrying because it often signals reduced kidney function. Mild, isolated increases may reflect dehydration, medications, or muscle injury and can be reversible; persistent or rising creatinine suggests chronic or acute kidney disease and requires evaluation (repeat labs, eGFR, urine tests, imaging). Seek prompt medical advice if levels rise rapidly or you have swelling, fatigue, nausea, or low urine output.