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Serum Creatinine (Creatinine Level)

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 how well your kidneys are filtering blood.

Quick summary

["Kidney function depends on this test to check for potential problems early."]

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

Key facts at a glance

LOINC
26253-5
Short code
XR tomo IAC-Bl
Synonyms
XR tomo IAC-Bl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr-tomography
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 this test to evaluate kidney function, detect kidney disease, monitor chronic conditions like diabetes or heart disease, or check for dehydration or muscle disorders. It’s often used alongside other tests to assess overall kidney health.

What Does a High or Low Result Mean?

High levels may indicate reduced kidney function, fluid overload, or muscle breakdown, while low levels could suggest dehydration, overhydration, or certain liver or muscle conditions. Results alone don’t diagnose a specific issue but guide further evaluation.

How Is This Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where creatinine levels are measured using a specialized test that detects waste products in your blood.

What Should You Do Before the Test?

No special preparation is needed unless instructed by your doctor. Avoid heavy exercise or consuming large amounts of protein the day before if your doctor advises it, as it may affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for monitoring kidney health and identifying early signs of kidney damage. Elevated levels often correlate with chronic kidney disease, while persistently low levels may warrant investigation into other conditions affecting fluid balance or muscle function.

Short name

Creatinine

Frequently asked questions

How often should I get this test?
Frequency depends on your health status. People with kidney disease, diabetes, or heart conditions may need this test more often, while healthy individuals may only need it periodically or when symptoms arise.
Can diet affect my creatinine levels?
Yes, high-protein diets or dehydration can temporarily raise creatinine levels. Your doctor may recommend dietary adjustments or timing the test around meals if needed.
What if my results are abnormal?
If results are outside expected ranges, your doctor will discuss next steps, which may include retesting, additional tests, or lifestyle changes to manage underlying conditions.
  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