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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. It helps assess how well your kidneys are filtering blood.

Quick summary

["Kidney function check via blood waste product levels."]

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

Key facts at a glance

LOINC
21522-8
Short code
ENA SM+RNP IgG Ser-aCnc
Synonyms
ENA SM+RNP IgG Ser-aCnc
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?

Your doctor may order this test to evaluate kidney function, check for kidney disease, monitor chronic conditions like diabetes or heart disease, or assess kidney damage from medications or toxins.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or hand to draw blood. If you’re on a blood thinner, inform your doctor beforehand.

What the Results Mean

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

Common Causes of Abnormal Results

Elevated creatinine can result from kidney disease, dehydration, or conditions that reduce blood flow to kidneys. Low levels may occur with muscle wasting, liver disease, or severe dehydration.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

Why might my creatinine levels be higher than usual?
Possible reasons include kidney disease, dehydration, severe muscle breakdown, or conditions that restrict blood flow to the kidneys (e.g., heart failure). Your doctor will review your symptoms and other test results to determine the cause.
Can diet affect creatinine levels?
Dietary protein intake can influence creatinine levels, but the effect is usually small. High-protein diets may temporarily raise levels, while very low-protein diets might lower them. Your doctor will consider overall health, not just diet, when interpreting results.
How often should I get this test?
Frequency depends on your health condition. People with kidney disease, diabetes, or heart conditions may need regular monitoring. Your doctor will schedule tests based on your specific needs and medical history.
  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