Serum Creatinine: Understanding This Key Kidney Function Marker

Serum creatinine is a blood test used to assess kidney function by measuring the level of creatinine, a waste product from muscle metabolism, in the bloodstream. The kidneys filter creatinine out of the blood, so high levels can indicate impaired kidney function or kidney disease. Normal ranges for serum creatinine are typically 0.6 to 1.2 mg/dL for men and 0.5 to 1.1 mg/dL for women. Elevated levels suggest the kidneys may not be filtering waste properly, which can be caused by conditions like chronic kidney disease or acute kidney injury.

What is Serum Creatinine?
- Creatinine is a waste product that comes from the normal wear and tear of muscles. The kidneys filter creatinine out of the blood and excrete it in urine.
- Serum creatinine levels are a key indicator of kidney function, as they reflect how well the kidneys are filtering waste.
Normal Ranges:
- For men, the normal range is approximately 0.6 to 1.2 mg/dL.
- For women, it’s typically 0.5 to 1.1 mg/dL, as women generally have less muscle mass.
- These ranges can vary slightly based on age, muscle mass, and overall health.
What Do High Serum Creatinine Levels Indicate?
- High serum creatinine levels may suggest that the kidneys are not functioning properly, potentially indicating:
  - Chronic kidney disease (CKD)
  - Acute kidney injury
  - Dehydration or blockage in the urinary tract.
- Kidney function can be further evaluated with the glomerular filtration rate (GFR), which is often estimated using creatinine levels.
Why is Serum Creatinine Important?
- It’s a reliable marker of kidney health and is frequently monitored in patients with conditions that affect the kidneys, such as diabetes, high blood pressure, and heart disease.
- Early detection of elevated creatinine allows for timely intervention to prevent or manage kidney disease.

Recommended Tests

Estimated Glomerular Filtration Rate (eGFR): This test uses serum creatinine levels to estimate how well the kidneys are filtering blood. It is a critical tool for diagnosing and monitoring chronic kidney disease (CKD).
- eGFR Test

Urea: Urea is another waste product filtered by the kidneys, and high levels can also indicate impaired kidney function. This test is often paired with serum creatinine to assess overall kidney health.
- Urea Test