Skip to content

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 simple blood test."]

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

Key facts at a glance

LOINC
14364-4
Short code
Gram Stn Eye
Synonyms
Gram Stn Eye
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
gram-stain
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 check for kidney problems, monitor kidney disease, or evaluate overall kidney function. It’s often used alongside other tests like blood urea nitrogen (BUN) to diagnose conditions like chronic kidney disease or acute kidney injury.

What Does a High or Low Level Mean?

High levels may indicate poor kidney function or conditions like dehydration, muscle disorders, or heart failure. Low levels are less common but could suggest overhydration or certain liver or muscle diseases.

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 is measured using a method called enzymatic analysis.

What Are Common Causes of Abnormal Results?

Changes in creatinine levels can result from kidney issues, dehydration, muscle breakdown, or certain medications. It’s important to discuss any symptoms or medications with your doctor.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Creatinine is a waste product filtered by the kidneys. Elevated levels suggest impaired kidney function, while persistently low levels may warrant further investigation into potential causes like fluid overload or muscle wasting.

Short name

Creatinine

Frequently asked questions

What if I’m Pregnant or Have Kidney Disease?
If you’re pregnant or have a history of kidney disease, your doctor may monitor creatinine levels more closely to ensure your kidneys are working properly. Pregnancy can also affect kidney function, so regular check-ups are important.
Do I Need to Prepare for This Test?
No special preparation is needed, but you may be asked to avoid certain medications or foods that could affect results. Always follow your doctor’s instructions.
Can Diet or Exercise Affect My Creatinine Levels?
Dietary protein intake can influence creatinine levels, as muscle breakdown produces this waste product. However, short-term changes in diet or exercise are unlikely to cause significant fluctuations unless you have kidney issues.
  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