Skip to content

Serum Creatinine (Creatinine Concentration)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood serum. It helps assess kidney function by reflecting how well your kidneys filter blood.

Quick summary

["A key indicator of kidney health and function."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
109167-7
Short code
C trach C Ab Msmt Ser
Synonyms
C trach C Ab Msmt Ser
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 levels can rise if your kidneys aren’t working as well as they should, which may signal early kidney damage or disease. It’s often used alongside other tests to monitor kidney function over time, especially in people with risk factors like diabetes, high blood pressure, or a family history of kidney problems.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into a vein in your arm to draw blood. If you’re on a blood thinner, let your healthcare provider know before the test.

What the Results Mean

Results are typically reported as a concentration in milligrams per deciliter (mg/dL). While reference ranges vary by lab, higher than expected levels may suggest kidney issues, while lower levels could indicate dehydration or muscle loss. Your doctor will interpret results in the context of your overall health.

Common Causes of Abnormal Results

Creatinine levels can be affected by factors like dehydration, muscle mass, or certain medications. Chronic kidney disease, acute kidney injury, or conditions like heart failure may also lead to elevated levels. Low levels might occur with severe dehydration or malnutrition.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Serum Creatinine

Frequently asked questions

Why might my doctor order this test?
Your doctor may order this test to check for kidney problems, monitor chronic conditions like diabetes or heart disease, or evaluate symptoms such as swelling, fatigue, or changes in urine output. It’s also used to assess kidney function before certain procedures or surgeries.
What if my results are out of the normal range?
If your results are higher than expected, your doctor may recommend further testing or adjustments to your treatment plan, such as managing blood pressure or diabetes. If levels are lower, they may investigate potential causes like dehydration or muscle loss. Always discuss your results with your healthcare provider.
Can diet or exercise affect this test?
Dietary changes like eating more protein or drinking less water can temporarily affect creatinine levels. However, your doctor will consider your overall health and lifestyle when interpreting results. Avoiding strenuous exercise before the test may help ensure accurate results, as muscle activity can slightly influence creatinine levels.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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