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Serum Creatinine (Creatinine)

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

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood. It helps assess kidney function.

Quick summary

["Your kidneys filter waste from blood; high creatinine may signal kidney problems."]

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

Key facts at a glance

LOINC
28400-0
Short code
ILIVEFORTODAY
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
reported-living-hiv
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 help doctors check how well your kidneys are working. Kidneys filter waste from your blood, including creatinine. If levels are too high, it may mean your kidneys aren’t working as they should, which can happen for many reasons, including infections, dehydration, or conditions like diabetes or high blood pressure.

What to Expect Before the Test

You’ll likely have a simple blood draw from a vein in your arm. No special preparation is needed, but tell your doctor about any medications or recent illnesses, as they may affect results.

Possible Results and Their Meaning

Results are compared to a general reference range, but individual values can vary based on age, sex, muscle mass, and overall health. Higher levels may indicate kidney issues, while lower levels might suggest dehydration or muscle loss.

Common Causes of Abnormal Results

High creatinine levels can be caused by kidney disease, dehydration, severe muscle injury, or conditions like heart failure or diabetes. Low levels may occur with dehydration, liver disease, or malnutrition.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

Could my creatinine level be affected by my diet?
Yes, eating a high-protein diet or consuming foods with creatinine (like red meat) can temporarily raise levels. However, this is usually short-term and doesn’t replace long-term kidney monitoring.
What if my test shows kidney problems?
If your creatinine is elevated, your doctor may order more tests (like urine tests or imaging) to check kidney function further. Treatment depends on the cause, which could include medications, lifestyle changes, or managing underlying conditions.
How often should I get this test?
Your doctor will decide based on your health. People with kidney disease or risk factors (like diabetes or high blood pressure) may need this test more often, while others might get it once a year or less.
  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