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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 breakdown, in your blood. It helps assess how well your kidneys are filtering blood.

Quick summary

["Kidney function check: creatinine helps doctors see if your kidneys are working properly."]

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

Key facts at a glance

LOINC
67878-9
Short code
FACILITYNAME
Synonyms
—
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 It’s Done

Your doctor may order this test if you have symptoms like fatigue, swelling, or changes in urine output. It’s also used to monitor kidney health in people with diabetes, high blood pressure, or other conditions that affect the kidneys.

What to Expect

A small blood sample is taken from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The test is quick and doesn’t require special preparation.

What the Results Mean

Higher than expected levels may suggest kidney problems, while very low levels could indicate muscle disorders or other health issues. Your doctor will interpret results in relation to your overall health.

Common Causes of Abnormal Results

Elevated creatinine can result from dehydration, kidney disease, or conditions that reduce blood flow to the kidneys. Low levels might be linked to muscle loss, liver disease, or certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

How often do I need this test?
Your doctor will decide how often you need this test based on your health condition. For example, people with kidney disease may need it more frequently, while others might only need it once.
Can I eat or drink before the test?
No special preparation is needed, but avoid excessive alcohol or very salty foods 24 hours before the test if instructed by your doctor.
What if my results are out of the normal range?
If your results are abnormal, your doctor will discuss them with you and may recommend further tests or changes to your treatment plan.
  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