Serum or Plasma Creatinine Concentration (Mass Concentration)
This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood or plasma. It helps assess how well your kidneys are filtering blood.
["A key measure of kidney function and filtering efficiency."]
Key facts at a glance
- LOINC
- 10002-4
- Short code
- R wave dur L-II
- Synonyms
- R wave dur L-II
- 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 in Kidney Health
Creatinine levels help doctors determine if your kidneys are working properly. High levels may indicate reduced kidney function or kidney disease, while low levels could suggest overhydration or muscle disorders.
How the Test Works
Your blood or plasma is collected and analyzed using a method that detects creatinine’s concentration. The test does not require fasting and is typically done as part of a routine kidney function panel.
When You Might Need This Test
Your doctor may order this test if you have symptoms like swelling, fatigue, frequent urination, or if you have a history of kidney problems, diabetes, or high blood pressure.
What to Expect Before the Test
No special preparation is needed. You may drink water beforehand, but avoid alcohol or excessive fluids 24 hours before testing to get an accurate result.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Creatinine
Frequently asked questions
How does creatinine relate to kidney function?
Your doctor will determine the frequency based on your health status. Regular monitoring may be recommended if you have chronic kidney disease, diabetes, or other conditions affecting kidney function.
What if my results are abnormal?
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