Serum Creatinine (with optional 24-hour urine collection for creatinine clearance calculation)
This test measures the level of creatinine, a waste product from muscle metabolism, in your blood. It helps assess kidney function and filter efficiency.
["Creatinine levels help doctors check how well your kidneys are working."]
Key facts at a glance
- LOINC
- 54410-6
- Short code
- DAT C3-Sp Reag RBC Ql
- Synonyms
- DAT C3-Sp Reag RBC Ql
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- 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
- 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: Kidney Health
Creatinine is a byproduct of muscle breakdown that your kidneys filter out of your blood. High levels may indicate impaired kidney function, while low levels could suggest dehydration or muscle loss. This test is often used alongside other measures to monitor kidney health, especially in people with diabetes, high blood pressure, or a history of kidney disease.
What to Expect Before the Test
No special preparation is needed for a blood creatinine test. You may have a small needle inserted into your arm to draw blood. If your doctor orders a 24-hour urine creatinine test, you’ll need to collect all urine for a full day (starting after the first void) and return it to the lab.
What the Results Mean
Results are typically reported in milligrams per deciliter (mg/dL) for blood tests. A 24-hour urine test measures total creatinine excreted over 24 hours. While reference ranges vary by lab, higher than expected levels may signal kidney issues, while lower levels may need further investigation.
Common Causes of Abnormal Results
High creatinine levels can result from kidney disease, dehydration, severe muscle damage, or conditions that reduce blood flow to the kidneys. Low levels may occur with dehydration, low muscle mass, or certain liver or heart conditions. Your doctor will consider your full medical picture when interpreting results.
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 key indicator of kidney function. They help diagnose kidney disease, monitor progression, and guide treatment decisions. In some cases, creatinine clearance (calculated from urine and blood tests) provides a more accurate picture of kidney function than blood creatinine alone.
Short name
Creatinine
Frequently asked questions
How often should I get this test?
Can diet or exercise affect my creatinine levels?
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 17, 2026. · Read our editorial policy