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

Quick summary

["A creatinine test helps check kidney function by measuring waste in your blood."]

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

Key facts at a glance

LOINC
14145-7
Short code
GH 40M p chal SerPl-mCnc
Synonyms
GH 40M p chal SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 like creatinine from your blood. High levels can signal kidney problems, including reduced kidney function or damage. Low levels may suggest overhydration or muscle disorders.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a larger panel. Drink plenty of water the day before to ensure accurate results.

What the Results Mean

Results are compared to a general reference range, but individual ranges can vary by lab. High creatinine levels may indicate kidney issues, while very low levels could raise concerns about hydration or muscle breakdown.

Common Causes of Abnormal Results

High creatinine levels can result from kidney disease, dehydration, or conditions affecting muscle metabolism. Low levels may occur with overhydration or certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

Will I need to prepare for this test?
No special preparation is typically required, but your doctor may advise fasting or hydration adjustments depending on the test’s context.
What does a high creatinine level mean?
A high level suggests your kidneys may not be filtering blood as well as they should, which could indicate kidney problems or other health conditions.
Can diet affect creatinine levels?
Dietary protein intake may influence creatinine levels, but your doctor will interpret results in the context of your overall health 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