Serum or Plasma Creatinine Concentration
This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood. 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
- 34188-3
- Short code
- nRBC Bld Ql
- Synonyms
- nRBC Bld Ql
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 4.2
- Ref high
- 5.9
- Critical range
- 2 N/A – 7 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85041
- SNOMED
- 900000000000003001
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters
Creatinine levels can indicate how well your kidneys are working. High levels may suggest kidney damage or disease, while low levels could be due to muscle loss or other conditions. Your doctor may order this test to monitor kidney health, especially if you have a history of kidney problems, diabetes, or high blood pressure.
How the Test Works
A small blood sample is taken from your arm. The lab then uses a specialized test to measure the creatinine concentration in your serum or plasma. The result helps determine how efficiently your kidneys remove waste products from your blood.
What to Expect Before the Test
You may not need any special preparation. However, if you’re taking certain medications (like some diuretics or contrast dyes for imaging), your doctor may advise you to avoid them before the test. Always follow your healthcare provider’s instructions.
Possible Results and Next Steps
Results are typically reported in milligrams per deciliter (mg/dL) or micromoles per liter (µmol/L). Your doctor will compare your result to your baseline or reference ranges to check for any changes. If your levels are unusually high, you may need further testing or treatment to manage kidney function.
Reference range
Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Creatinine levels are a vital indicator of kidney function. Elevated levels often signal impaired kidney function, which can lead to complications like fluid buildup, electrolyte imbalances, or even heart problems. Regular monitoring helps detect kidney issues early and allows for timely medical intervention. Conversely, very low levels may warrant further investigation to rule out conditions like muscle wasting or dehydration.
Short name
Creatinine
Frequently asked questions
How often should I get this test?
Can diet or exercise affect my creatinine levels?
What if my test 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 17, 2026. · Read our editorial policy