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Serum or Plasma Creatinine Concentration (Substance Concentration)

Published: August 9, 2026Updated: August 17, 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 and detect early kidney problems."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
7366-8
Short code
Cocksfoot BasoBnd Ab Qn
Synonyms
Cocksfoot BasoBnd Ab Qn
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
lhr
CPT
82553
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test to evaluate kidney health, monitor chronic kidney disease, or check for conditions like dehydration, muscle disorders, or kidney-related illnesses. It’s also used before certain procedures to assess kidney function risk.

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 broader metabolic panel. Avoid using certain supplements (like creatine) that could affect results.

How the Test Works

A blood sample is drawn from a vein, usually in your arm. The lab then measures the creatinine concentration using a specialized chemical test, often automated and precise.

What the Results Mean

Higher-than-normal levels may indicate reduced kidney function, while lower levels could suggest dehydration, overhydration, or muscle breakdown. Your doctor will interpret results in relation to your overall health and medical history.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: whole-blood

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine Level

Frequently asked questions

How often should I get this test?
Your doctor will determine the frequency based on your health condition. For example, people with kidney disease may need tests every few months, while healthy individuals may only need it occasionally or as part of routine check-ups.
Can diet affect my creatinine levels?
Yes, high-protein foods or muscle breakdown (e.g., from intense exercise) can temporarily raise creatinine levels. Avoiding excessive protein intake for a day or two before testing may help stabilize results.
What if my results are abnormal?
If your results are outside the expected range, your doctor will discuss next steps, which could include additional tests, lifestyle adjustments, or treatment for underlying conditions like kidney disease or dehydration.
  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 17, 2026. · Read our editorial policy