Serum or Plasma Creatinine 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 creatinine test helps check kidney function by evaluating how well your kidneys remove waste from your blood."]
Key facts at a glance
- LOINC
- 45183-1
- Short code
- N men Islt Aggl
- Synonyms
- N men Islt Aggl
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- aggl
- 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 naturally filtered out by your kidneys. If your kidneys aren’t working properly, creatinine levels can build up in your blood. This test is a key part of checking kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output.
What to Expect Before the Test
You may be asked to fast for a few hours before the test, but this depends on your doctor’s instructions. A simple blood draw is all that’s needed—just a small needle prick at your vein. No special preparation is usually required beyond showing up rested and hydrated.
What the Results Mean
Higher-than-normal levels may signal kidney problems, while lower levels could indicate dehydration or muscle loss. Your doctor will compare your results to your health history and other tests to interpret them accurately.
Common Causes of Abnormal Results
Kidney disease, dehydration, or conditions like heart failure or diabetes can affect creatinine levels. Other factors, such as recent exercise or certain medications, might also influence the results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Creatinine levels are a critical marker for kidney function. Elevated levels often indicate impaired kidney filtration, which can lead to long-term health risks like fluid buildup, electrolyte imbalances, or even kidney failure if untreated. Low levels may suggest dehydration or reduced muscle mass, but further evaluation is needed to rule out other causes.
Short name
Creatinine
Frequently asked questions
Why might my creatinine test be done?
Could food or medications affect my test results?
What if my results are out of the normal range?
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