Serum Creatinine (Creatinine Level)
This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood serum. It helps assess how well your kidneys are filtering blood.
["A creatinine test helps evaluate kidney function and detect early kidney problems."]
Key facts at a glance
- LOINC
- 33887-1
- Short code
- PT 2h NP PPP
- Synonyms
- PT 2h NP PPP
- Category
- chemistry
- Sample
- plasma
- Container
- Lavender-top (EDTA) or Green-top (Heparin)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- coag-tissue-factor-induced-factor-substitution-h-post-incubation-after-addition-of-normal-plasma
- CPT
- 85610
- SNOMED
- 396252006
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters
Creatinine is a byproduct of muscle breakdown and is normally filtered out of your blood by your kidneys. High levels can indicate poor kidney function, while low levels may suggest overhydration or muscle wasting. This test is often used alongside other measures, like blood urea nitrogen (BUN), to assess kidney health.
What to Expect Before the Test
No special preparation is needed for this test. You may have a small needle inserted into your arm to draw blood. If you’re on a low-protein diet or have had recent muscle activity, your doctor may advise timing your test to avoid temporary fluctuations in results.
Common Causes of Abnormal Results
Elevated creatinine levels may signal kidney disease, dehydration, or conditions affecting muscle metabolism (e.g., severe muscle injury or illness). Low levels could suggest dehydration, overhydration, or conditions like liver disease or malnutrition that reduce muscle mass.
What the Results Mean
Your results will be compared to a reference range provided by your healthcare team. While ranges vary by lab, they reflect typical values for healthy adults. Your doctor will interpret results in the context of your overall health, other tests, and symptoms you may have.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Creatinine levels are a key indicator of kidney function. Chronic kidney disease (CKD) often shows up early with subtle changes in creatinine, so regular monitoring is important for people at higher risk (e.g., those with diabetes, hypertension, or a family history of kidney disease). It can also help guide treatment decisions, such as adjusting medications that affect kidney function.
Short name
None
Frequently asked questions
How often should I get this test?
What can affect my creatinine test results?
Do I need to fast for this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 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 16, 2026. · Read our editorial policy