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Serum 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. It helps assess kidney function.

Quick summary

["A creatinine test helps doctors check how well your kidneys are filtering waste from your blood."]

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

Key facts at a glance

LOINC
3228-4
Short code
Fact XI Ag PPP IA-aCnc
Synonyms
Fact XI Ag PPP IA-aCnc
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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

What Is Creatinine?

Creatinine is a byproduct of muscle breakdown that your kidneys normally filter out of your blood. Levels can rise if your kidneys aren’t working properly or if you have conditions that affect muscle function.

Why Might You Need This Test?

Your doctor may order this test to monitor kidney health, especially if you have diabetes, high blood pressure, or a history of kidney disease. It can also help diagnose conditions like chronic kidney disease or acute kidney injury.

How Is the Test Done?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to measure creatinine levels.

What Do Results Mean?

Higher-than-normal levels may suggest kidney problems, while lower levels could indicate muscle loss or certain metabolic conditions. Your doctor will interpret results in relation to your overall health and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Creatinine levels are a key indicator of kidney function, as they reflect how well your kidneys are removing waste from your bloodstream. Elevated levels often signal impaired kidney function, which can lead to complications like fluid buildup, electrolyte imbalances, or even heart problems if untreated. Regular monitoring is important for people with chronic kidney disease or those at higher risk.

Short name

Creatinine

Frequently asked questions

Why do doctors check creatinine levels regularly?
Doctors check creatinine levels to track kidney function over time, especially if you have conditions like diabetes or high blood pressure that can damage kidneys. It helps them spot early signs of kidney problems so treatment can begin sooner.
What causes creatinine levels to be higher than normal?
Higher creatinine levels can be caused by kidney disease, dehydration, severe muscle damage, or certain medications. Other factors like age, sex, and muscle mass can also affect results.
Do I need to prepare for this test?
No special preparation is needed, but you may be asked to avoid certain medications or foods for a few days before the test if instructed by your doctor.
  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