Serum or Plasma Creatinine Concentration
This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood or urine. It helps assess kidney function.
["A creatinine test helps check how well your kidneys are filtering waste from your blood."]
Key facts at a glance
- LOINC
- 10071-9
- Short code
- S' wave dur L-AVL
- Synonyms
- S' wave dur L-AVL
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ekg
- 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 by your kidneys. High levels may indicate kidney problems, while low levels could suggest dehydration or muscle loss. This test is often used alongside other kidney function tests to diagnose and monitor conditions like chronic kidney disease.
What to Expect Before the Test
No special preparation is needed for a blood test, but for a urine test, you may need to collect a sample over a 24-hour period. Avoid taking certain medications (like NSAIDs) that could affect kidney function before testing.
How the Test Works
Blood: A small sample is taken from your arm and sent to a lab for analysis. Urine: You may collect all urine for 24 hours, or a single sample may be tested depending on the test type. The lab measures creatinine concentration using methods like enzymatic or nephelometric techniques.
Possible Results and What They Mean
Results are typically reported in milligrams per deciliter (mg/dL) for blood or milligrams per gram of creatinine clearance for urine. Higher than expected levels may signal impaired kidney function, while lower levels may need further investigation.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Creatinine Level
Frequently asked questions
What does a high creatinine level mean?
A low creatinine level may suggest dehydration, muscle wasting, or liver disease, which can affect muscle breakdown and creatinine production. It’s less common but can sometimes indicate kidney issues if other symptoms are present. Your doctor may ask for additional tests to understand the cause.
Dietary changes, such as eating more protein, can temporarily raise creatinine levels. However, this is usually short-term and not a cause for concern unless you have kidney issues. Always discuss dietary changes with your healthcare provider.
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