Serum or Plasma Creatinine Concentration (Mass 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 measuring waste in your blood."]
Key facts at a glance
- LOINC
- 7455-9
- Short code
- Lemon IgG Qn
- Synonyms
- Lemon IgG Qn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82784
- 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 Is This Test Done?
Your doctor may order a creatinine test to monitor kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output. It’s also used before certain procedures, to check for kidney disease, or to evaluate kidney function in people with diabetes or high blood pressure.
What Does a High or Low Level Mean?
High levels may indicate kidney problems, dehydration, or conditions that reduce blood flow to the kidneys. Low levels could suggest overhydration, muscle breakdown, or liver disease, though this is less common. Your doctor will interpret results in relation to your overall health.
Sample Collection and Preparation
A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab for testing. If you’re on dialysis or have certain medications, your doctor may advise timing your test around your treatment schedule to avoid interference.
What to Expect Before the Test
No special preparation is needed, but inform your doctor about any medications you’re taking, especially those that affect kidney function (e.g., NSAIDs, certain antibiotics). Avoid strenuous activity or eating heavy meals before the test if instructed.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Creatinine Level
Frequently asked questions
A creatinine test is a key part of a kidney function panel, often paired with blood urea nitrogen (BUN) to assess how well your kidneys are filtering waste. It’s also used to monitor progression of chronic kidney disease, guide dialysis timing, or evaluate response to treatments for conditions like heart failure or severe dehydration.
If your results are higher than expected, your doctor may recommend further tests, like additional bloodwork or imaging, to investigate kidney issues. If levels are low, they may check for other causes like muscle loss or liver disease. Follow-up depends on your symptoms and overall health.
Dietary changes alone won’t drastically alter creatinine levels, but eating a high-protein diet may temporarily increase muscle breakdown, which could slightly raise levels. Hydration status also matters—dehydration can raise creatinine, while overhydration may lower it.
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