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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 simple blood test."]

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

Key facts at a glance

LOINC
33396-3
Short code
N men sg A+C+W135+Y Ag Ser Ql
Synonyms
N men sg A+C+W135+Y Ag Ser Ql
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 Is This Test Done?

Your doctor may order this test to check for kidney disease, monitor kidney function in people with diabetes or high blood pressure, or evaluate kidney health before certain procedures. It can also help determine how well dialysis is working.

What Does a High or Low Level Mean?

High levels may indicate kidney problems, dehydration, or conditions that increase muscle breakdown. Low levels can sometimes suggest overhydration or liver disease, though this is less common.

How Is the Test Performed?

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

What Should You Do Before the Test?

Avoid strenuous exercise or heavy meals 24 hours before the test. If you take certain medications (like NSAIDs), discuss this with your doctor, as they may affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

Will I feel any pain or discomfort during the test?
You may feel a slight pinch or sting when the needle is inserted, but it usually goes away quickly. Most people experience minimal discomfort afterward.
Can diet or hydration affect my creatinine levels?
Eating a high-protein diet or drinking large amounts of water can temporarily influence results. Your doctor may advise you to follow a standard diet for 24 hours before testing.
How often will I need this test?
Frequency depends on your health condition. Some people need it yearly, while others may require it more often if they have chronic kidney disease or other related 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