Serum or Plasma Creatinine Concentration (Standard Method)
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 measuring waste removal efficiency.
Key facts at a glance
- LOINC
- 31910-3
- Short code
- N men sg A+C+W135+Y Ag Spec Ql
- Synonyms
- N men sg A+C+W135+Y Ag Spec Ql
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 filtered out of your blood by your kidneys. High levels may indicate poor kidney function, while low levels could suggest overhydration or muscle loss. This test is often used alongside other kidney function tests to diagnose conditions like chronic kidney disease.
What to Expect Before the Test
No special preparation is needed unless instructed by your healthcare provider. You may have a small needle inserted into your arm to draw blood. If a urine sample is involved (e.g., a 24-hour collection), follow specific instructions to collect the sample accurately.
What the Results Mean
Results are typically reported as a concentration in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). While reference ranges vary by lab, higher-than-normal levels may signal kidney issues, while very low levels may warrant further investigation.
Common Conditions Monitored
This test is commonly used to monitor kidney disease, dehydration, muscle disorders, and to evaluate the effectiveness of treatments for conditions like heart failure or certain medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Creatinine levels are a key indicator of kidney function because they reflect how well your kidneys remove waste products from your blood. Elevated levels can signal early kidney damage, while persistently low levels may require additional evaluation to rule out conditions like severe dehydration, muscle wasting, or certain metabolic disorders. It’s often used in conjunction with other tests, such as blood urea nitrogen (BUN), to assess kidney health comprehensively.
Short name
Creatinine Level
Frequently asked questions
How often should I get this test?
What can affect my creatinine levels?
Do I need to fast before 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