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Serum Creatinine (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 to assess kidney function.

Quick summary

["A creatinine test helps 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
40635-5
Short code
Kappa LC Ser Ql IFE
Synonyms
Kappa LC Ser Ql IFE
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
immunofixation
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 This Test Matters

Creatinine levels can rise if your kidneys aren’t working as well as they should. High levels may signal early kidney problems, while very low levels might suggest dehydration or muscle disorders.

What to Expect Before the Test

You’ll typically have a small blood sample drawn from your arm. No special preparation is needed, but inform your provider if you’re taking certain medications or have recent illness.

Common Causes of Abnormal Results

Elevated creatinine can result from kidney disease, dehydration, or muscle breakdown. Low levels may occur with fluid overload or certain muscle disorders.

When You Might Need This Test

Doctors often order creatinine tests to monitor kidney health, especially during pregnancy, after surgery, or if you have conditions like diabetes or high blood pressure.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Creatinine levels are a key indicator of kidney function, helping doctors diagnose and manage conditions like chronic kidney disease, acute kidney injury, or electrolyte imbalances. It’s also used alongside other tests (like blood urea nitrogen) to assess overall kidney performance.

Short name

Creatinine

Frequently asked questions

Why do doctors check creatinine levels regularly if I have diabetes or high blood pressure?
These conditions can strain your kidneys over time, so monitoring creatinine helps track kidney health and adjust treatments as needed. It’s part of routine care to prevent complications.
Can diet affect my creatinine test results?
Dietary changes like high-protein meals can temporarily raise creatinine levels, but this usually returns to normal after a few days. Your provider may suggest fasting or timing the test around meals if needed.
What if my creatinine is higher than expected?
A higher creatinine level may signal kidney issues, but it can also be caused by dehydration, muscle injury, or other factors. Your doctor will review your full medical picture and may recommend follow-up tests or adjustments to your care 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