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Serum or Plasma Creatinine Concentration (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. It helps assess how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney function by tracking waste removal."]

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

Key facts at a glance

LOINC
105139-0
Short code
MRA Spec
Synonyms
MRA Spec
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr-angio
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

Your kidneys normally filter waste products, including creatinine, from your blood. If your kidneys aren’t working well, creatinine levels can rise. High levels may signal kidney problems, even if you don’t have symptoms yet.

How the Test Works

A small blood sample is taken from your arm. The lab measures the creatinine concentration using a specialized test that detects its presence in your serum or plasma.

What to Expect Before the Test

No special preparation is needed, but you may want to drink plenty of fluids the day of the test to help your kidneys work normally.

Common Causes of Abnormal Results

Low levels might suggest dehydration or muscle breakdown, while high levels often indicate kidney disease, fluid overload, or conditions that reduce blood flow to the kidneys.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

How often should I get this test?
Your doctor will determine how often you need this test based on your health history, symptoms, and any ongoing conditions. For example, people with diabetes or high blood pressure may get it more frequently.
What does a normal result mean?
A normal result doesn’t mean your kidneys are perfectly healthy—it just means your creatinine level is within a general range that suggests your kidneys are working as expected for your body size and health.
Can diet affect my creatinine levels?
Yes, eating high-protein foods or drinking large amounts of fluids can temporarily affect creatinine levels. Your doctor may adjust timing or instructions if you have dietary restrictions.
  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