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Serum Creatinine (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

["A creatinine test helps check how well your kidneys are filtering blood."]

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

Key facts at a glance

LOINC
25419-3
Short code
MuV IgM Ser IA-aCnc
Synonyms
MuV IgM Ser IA-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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

What Is Creatinine?

Creatinine is a byproduct of muscle breakdown that your kidneys normally filter out of your blood. High levels may indicate kidney problems, while low levels could suggest muscle underuse or other conditions.

Why Might You Need This Test?

Doctors order creatinine tests to monitor kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output. It’s also used before certain procedures or medications to assess kidney function.

How Is the Test Done?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab for analysis. No special preparation is needed unless instructed otherwise.

What Do Results Mean?

Results are compared to a general reference range, but individual results depend on factors like age, sex, and overall health. High levels may signal kidney issues, while very low levels may warrant further investigation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Creatinine levels are a key marker for kidney function, as they reflect how well your kidneys are removing waste. Chronic kidney disease, dehydration, or certain medications can affect results, so follow-up may be needed if levels are abnormal.

Short name

Creatinine

Frequently asked questions

Why was I asked to have this test?
Your doctor may have recommended this test to check kidney function, especially if you have symptoms like swelling, nausea, or changes in urine. It’s also used before surgeries or treatments that could impact your kidneys.
What does a high creatinine level mean?
A high creatinine level may suggest your kidneys aren’t working as well as they should, possibly due to kidney disease, dehydration, or other health conditions. Your doctor will discuss next steps based on your results.
Can diet affect creatinine levels?
Dietary protein intake can influence creatinine levels, but the test itself doesn’t measure protein directly. High-protein diets may slightly raise levels, while dehydration can also impact results. Follow your doctor’s advice for dietary guidance.
  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