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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 or plasma. 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
10030-5
Short code
R' wave dur L-V3
Synonyms
R' wave dur L-V3
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ekg
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 levels can indicate how well your kidneys are working. High levels may suggest kidney damage or disease, while low levels might raise concerns about muscle problems or dehydration.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before a blood test. For a urine test, you might collect a sample over 24 hours or provide a random sample. Hydration can affect results, so drink as usual unless instructed otherwise.

Common Causes of Abnormal Results

Elevated creatinine levels can occur with kidney disease, dehydration, severe muscle breakdown, or conditions like heart failure. Low levels may indicate dehydration, low muscle mass, or liver disease.

How Results Are Interpreted

Results are compared to a baseline or reference range provided by your healthcare provider. They consider your age, sex, and overall health. Repeated tests may be needed to track changes over time.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

How often should I get this test?
Your doctor may recommend this test periodically if you have kidney-related conditions, diabetes, high blood pressure, or a family history of kidney disease. Regular monitoring helps manage long-term health and prevent complications.
Can diet affect creatinine levels?
Yes, high-protein diets or muscle-building activities can temporarily increase creatinine levels. Avoiding excessive protein or muscle strain for a few days before testing may help stabilize results.
What if my results are out of the normal range?
If your results are abnormal, your doctor will discuss next steps, which may include further testing, lifestyle adjustments, or treatment for underlying conditions. Follow-up visits will help track progress.
  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