Creatinine Blood Test: Purpose, Preparation, and Understanding Your Results
A creatinine blood test measures the amount of creatinine, a waste product produced by normal muscle metabolism, in your blood to evaluate how well your kidneys are filtering and functioning. When kidney function is impaired, creatinine builds up in the bloodstream, making it a key marker of kidney health. The test requires a simple blood draw from a vein in your arm and is usually part of a comprehensive metabolic panel (CMP) or basic metabolic panel (BMP) that also includes blood urea nitrogen (BUN), glucose, and electrolytes. To prepare, fast for 8-12 hours, avoid strenuous exercise for 24 hours, stay well hydrated, and tell your doctor about any medications or supplements you take. Typical reference ranges are about 0.7-1.3 mg/dL for men and 0.6-1.1 mg/dL for women, and your provider will often review your result alongside your estimated glomerular filtration rate (eGFR) for a fuller picture of kidney function.
{"Creatinine is a waste product that builds up in your blood when your kidneys cannot filter it properly","Higher than normal levels may indicate kidney problems, while lower levels can sometimes occur with decreased muscle mass","The test is often part of routine health checkups and is used to monitor kidney function over time","Results are typically reported in mg/dL and should be interpreted by your healthcare provider alongside other tests","Preparing for the test usually requires fasting and avoiding strenuous exercise for 24 hours before sample collection"}
Key facts at a glance
- LOINC
- 2160-0
- Short code
- Creatinine
- Synonyms
- —
- Category
- kidney
- Sample
- serum
- Container
- Serum Separator Tube (SST) or Plain Red Top Tube
- Units
- mg/dL
- Ref low
- 0.6
- Ref high
- 1.3
- Critical range
- 0.3 mg/dL – 5 mg/dL
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- enzymatic
- CPT
- 82565
- SNOMED
- 273999004
- Specimen volume
- 1 mL serum minimum, 3-5 mL recommended
- Stability
- Room temperature: 24-72 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days
- Hemolysis max
- 50
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 1–3 hours
What is this test?
A creatinine blood test measures the amount of creatinine in your blood. Creatinine is a waste product produced by normal muscle metabolism. Your kidneys normally filter creatinine from your blood and eliminate it through urine. When kidney function is impaired, creatinine accumulates in the blood, making it a useful marker for assessing kidney health.
How is the test performed?
A healthcare professional will draw a blood sample from a vein in your arm. The sample is then sent to a laboratory for analysis. The test is usually part of a comprehensive metabolic panel (CMP) or basic metabolic panel (BMP), which may also include tests for blood urea nitrogen (BUN), glucose, and electrolytes.
How to prepare for the test
To ensure accurate results, follow these preparation guidelines: Fast (no food or drink except water) for 8-12 hours before the test. Avoid strenuous exercise for 24 hours before testing, as exercise can temporarily increase creatinine levels. Inform your doctor about any medications or supplements you are taking, as some drugs can affect creatinine levels. Stay well-hydrated unless otherwise instructed by your healthcare provider.
Understanding your results
Normal creatinine ranges vary based on age, sex, and muscle mass. Typical reference ranges are approximately 0.7-1.3 mg/dL for men and 0.6-1.1 mg/dL for women. Your healthcare provider will interpret your results in context with other factors and tests, such as your estimated glomerular filtration rate (eGFR), which provides a better picture of kidney function.
Reference range
Adult male: 0.7-1.3 mg/dL; Adult female: 0.6-1.1 mg/dL; Reference ranges may vary by laboratory and patient population. Pediatric ranges are age-dependent.mg/dL
No special preparation required. Ensure adequate hydration before sample collection. Avoid strenuous exercise 24 hours prior to collection as it may temporarily elevate creatinine levels.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings2
Short name
Creat
Part of panels
Frequently asked questions
What happens if my creatinine level is high?
How often should I have my creatinine tested?
Can I lower my creatinine level naturally?
What is the difference between creatinine and eGFR?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 10, 2026. · Read our editorial policy