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Serum Creatinine (Creatinine)

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

This test measures the level of creatinine, a waste product from muscle metabolism, in your blood to assess kidney function.

Quick summary

["Your kidneys filter waste from blood; high creatinine may signal kidney issues."]

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

Key facts at a glance

LOINC
57662-9
Short code
U1 snRNP Ab Ser IA-aCnc
Synonyms
U1 snRNP Ab 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
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 helps doctors check how well your kidneys are working. It’s a key part of kidney function tests, often used alongside blood urea nitrogen (BUN) to diagnose or monitor kidney disease.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw blood. If you’re on a low-protein diet or have certain medications, your doctor may advise adjustments.

What the Results Mean

Higher than expected levels may indicate reduced kidney function, while lower levels could suggest overhydration or muscle loss. Your doctor will compare your result to your baseline and overall health.

Common Causes of Abnormal Results

Elevated creatinine can result from dehydration, kidney disease, or conditions that affect muscle mass. Low levels may occur with fluid overload or severe muscle wasting.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine

Frequently asked questions

How often will I need this test?
Your doctor may order this test regularly if you have kidney problems, diabetes, high blood pressure, or other conditions that increase kidney risk. Frequency depends on your health plan and symptoms.
Can diet affect creatinine levels?
Yes, high-protein diets or muscle activity can temporarily raise creatinine. Your doctor may recommend monitoring if you’re on such diets or have kidney concerns.
What if my results are out of range?
Your doctor will discuss next steps based on your results, including lifestyle changes, further tests, or treatment adjustments if needed.
  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