Serum Creatinine (Creatinine Level)
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.
["Kidney function check: creatinine levels help determine if your kidneys are working properly."]
Key facts at a glance
- LOINC
- 6293-5
- Short code
- C4DRBC
- Synonyms
- C4d RBC Ql
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA) vacuum blood collection tube
- 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
- Method
- Flow cytometry
- CPT
- 86160
- SNOMED
- 44792005
- Specimen volume
- 3-5 mL of whole blood
- Stability
- Specimen should be processed within 24-48 hours of collection when stored at 2-8°C. Do not freeze whole blood. If testing is delayed, store at 2-8°C and analyze within stated stability limits per laboratory protocol.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
Why Your Kidneys Matter
Kidneys filter waste and extra fluids from your blood. Creatinine is a byproduct of muscle breakdown, and its levels can reflect how well your kidneys are working. High levels may suggest kidney problems, while very low levels can sometimes indicate muscle disorders or other conditions.
What to Expect During the Test
A simple blood sample is taken from a vein in your arm. No special preparation is needed, but fasting may be advised depending on your doctor’s instructions.
Common Causes of Creatinine Levels
Changes in creatinine levels can be influenced by factors like dehydration, muscle mass, certain medications, or kidney disease. High levels may indicate reduced kidney function, while low levels might need further evaluation to rule out other conditions.
When to Check Your Levels
Your doctor may order this test if you have symptoms like swelling, fatigue, or changes in urine output, or if you have a history of kidney issues.
Reference range
Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A
No fasting required. Patient should be well-hydrated. Inform the laboratory of any recent blood transfusions, as this may affect interpretation of results. Recent immunosuppressive therapy should be documented.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Creatinine
Frequently asked questions
Why might my creatinine level be higher than expected?
Do I need to fast before this test?
What if my creatinine level is 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