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Creatinine in Serum (Mass Concentration)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood serum. It helps assess kidney function.

Quick summary

["Your kidneys filter waste from blood; this test checks how well they’re working."]

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

Key facts at a glance

LOINC
56228-0
Short code
Codfish IgG4-mCnc
Synonyms
Codfish IgG4-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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?

Doctors may order a serum creatinine test to monitor kidney health, especially if you have symptoms like fatigue, swelling, or changes in urine output. It’s also used to guide treatments for conditions like diabetes or high blood pressure.

What to Expect During the Test

A small blood sample is taken from your arm. You may feel a slight pinch, but it’s quick and painless. No special preparation is needed unless instructed otherwise.

How the Results Are Used

Results help calculate your **estimated glomerular filtration rate (eGFR)**, a measure of kidney function. Abnormally high or low levels may signal kidney issues that need attention.

Common Causes of Abnormal Results

High levels might indicate poor kidney function, dehydration, or conditions like diabetes or heart disease. Low levels could suggest overhydration or liver/kidney problems, though this is rare.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Creatinine

Frequently asked questions

What does a high serum creatinine level mean?
A high level may mean your kidneys aren’t working as well as they should, possibly due to kidney disease, dehydration, or other health conditions like diabetes or heart problems. Your doctor will discuss this with you and may recommend further tests or adjustments to your treatment plan.
What if my creatinine level is low?
Low levels are less common but could suggest overhydration or, rarely, liver or kidney issues. Your doctor will review your medical history and other test results to understand the cause and guide next steps.
Do I need to fast before this test?
No fasting is required for this test. However, if you’re taking certain medications or have a condition that affects kidney function, your doctor may give specific instructions.
  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