Plasma or Serum Creatinine Concentration (Substance Concentration)
This test measures the amount of creatinine, a waste product from muscle breakdown, in your blood or plasma. It helps assess how well your kidneys are filtering blood.
["A creatinine test helps check kidney function and detect early kidney problems."]
Key facts at a glance
- LOINC
- 74542-2
- Short code
- PK/G6PD RBC-cRto
- Synonyms
- PK/G6PD RBC-cRto
- Category
- glucose
- 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
- true
- 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 is a byproduct of muscle metabolism and is normally filtered out by your kidneys. If your kidneys aren’t working well, creatinine builds up in your blood. This test helps doctors monitor kidney health, especially in people with diabetes, high blood pressure, or other conditions that can affect the kidneys.
What to Expect Before the Test
You won’t need to prepare for this test. It’s usually done by drawing blood from a vein in your arm. If you’re on dialysis, your doctor may recommend this test to check how well your kidneys are functioning outside the body.
What the Results Mean
Higher than expected levels may suggest kidney problems, while lower levels could indicate muscle loss or other conditions. Your doctor will interpret results in relation to your overall health and medical history.
Common Causes of Abnormal Results
Kidney disease, dehydration, heart failure, or certain medications can raise creatinine levels. Conversely, conditions like severe muscle wasting or liver disease might lower it. Always discuss any concerns with your healthcare provider.
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.
◆Associated findings1
Short name
Creatinine Level
Frequently asked questions
Why might my creatinine level be higher than usual?
What should I do if my creatinine level is low?
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 17, 2026. · Read our editorial policy