1. What is Creatinine?

Creatinine is a waste product formed from the normal breakdown of muscle tissue (from creatine). It’s commonly used as a marker to evaluate kidney function.

2. How is Creatinine Formed?

Creatinine is formed when creatine phosphate, an energy source in muscles, breaks down. This process happens at a fairly constant rate depending on your muscle mass.

3. What Does Creatinine Do?

It doesn't serve any functional role. It’s simply a byproduct to be excreted and is used by doctors to assess kidney health.

4. How is Creatinine Excreted?

Creatinine is filtered by the kidneys and removed from the body via urine. Since it’s not reabsorbed into the blood, it gives a clear indication of how well your kidneys are filtering waste.

5. What Does It Indicate in Blood?

Blood levels of creatinine help diagnose kidney problems and other conditions.

• Normal levels:
  • Men: 0.7 – 1.3 mg/dL
  • Women: 0.6 – 1.1 mg/dL
• High levels: May suggest kidney damage, dehydration, high protein diet, or muscle disease.
• Low levels: May indicate low muscle mass, liver disease, or malnutrition.

6. Related Tests

• Serum Creatinine: Measures creatinine in blood.
• Creatinine Clearance: Estimates how well the kidneys filter creatinine.
• eGFR: Estimated Glomerular Filtration Rate, derived from serum creatinine.
• Urine Creatinine: Measures how much is excreted in urine.

Summary Table