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Kidney Function

What is Serum Creatinine? Your Complete Guide

Creatinine is a waste product from normal muscle activity, filtered by your kidneys at a very steady rate. This makes it one of the most reliable markers for kidney function.

💡Simply Explained

Creatinine is waste produced by your muscles and filtered out by your kidneys at a steady rate. If it piles up in your blood, your kidneys' filter is clogging up. This is one of the most important kidney markers.

📏Normal Range

0.7 – 1.3mg/dL

Typical reference range. Your lab may use slightly different values.

LowNormalHigh
< 0.7 mg/dL0.7 – 1.3 mg/dL> 1.3 mg/dL

⬆️What High Serum Creatinine Means

Possible Causes

  • Chronic kidney disease (most common)
  • Dehydration
  • High muscle mass (bodybuilders)
  • Medications (NSAIDs, ACE inhibitors)
  • Acute kidney injury
  • Urinary tract obstruction

Foods That Can Help

  • Drink plenty of water (2.5-3 liters daily)
  • Reduce salt intake
  • Limit high-protein meals temporarily
  • Avoid excess potassium if kidney function is impaired
  • Cranberry juice (supports urinary health)

⬇️What Low Serum Creatinine Means

Possible Causes

  • Low muscle mass
  • Malnutrition
  • Liver disease
  • Pregnancy

Foods That Can Help

  • Adequate protein intake
  • No specific concerns

🏃Lifestyle Actions

If Your Serum Creatinine Is High

  • Stay very well hydrated
  • Avoid NSAIDs (ibuprofen, diclofenac) — they worsen kidney function
  • Monitor blood pressure — hypertension is the #1 enemy of kidneys
  • If diabetic, strict blood sugar control protects kidneys
  • Get eGFR calculated for accurate kidney staging

If Your Serum Creatinine Is Low

  • Usually not a concern
  • If very low with other symptoms, investigate muscle or liver conditions

🩺When to See a Doctor

High Serum Creatinine

Even mildly elevated creatinine is significant — by the time creatinine rises, 50%+ of kidney function may already be lost. See a doctor within 1-2 weeks for a proper kidney workup. Rapidly rising creatinine is urgent.

Low Serum Creatinine

Low creatinine is rarely concerning unless very low with muscle wasting.

🎯Did You Know?

Creatinine is a "lagging indicator" — your kidneys can lose up to half their function before creatinine rises above normal. That's why doctors increasingly use eGFR (estimated from creatinine) to catch kidney problems earlier.

❓Frequently Asked Questions

What is Serum Creatinine?

Creatinine is waste produced by your muscles and filtered out by your kidneys at a steady rate. If it piles up in your blood, your kidneys' filter is clogging up. This is one of the most important kidney markers.

What is the normal range for Serum Creatinine?

The typical normal range for Serum Creatinine is 0.7–1.3 mg/dL.

What causes high Serum Creatinine?

Chronic kidney disease (most common). Dehydration. High muscle mass (bodybuilders).

What causes low Serum Creatinine?

Low muscle mass. Malnutrition. Liver disease.

How can I check my Serum Creatinine levels?

You can check your Serum Creatinine levels with a routine blood test. Upload your lab report to ScanHealth for an instant, plain-language explanation.

Check Your Serum Creatinine Results Instantly

Upload your blood test report and get a plain-language explanation of your Serum Creatinine result — plus all other markers. Free.

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This guide is for informational purposes only and does not constitute medical advice. Reference ranges may vary by lab. Always consult a qualified healthcare provider for diagnosis and treatment.