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Plasma Creatinine (Creatinine Concentration)

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

This test measures the level of creatinine, a waste product from muscle metabolism that your kidneys filter from your blood.

Quick summary

["Your kidneys’ ability to filter waste is assessed by checking creatinine levels."]

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

Key facts at a glance

LOINC
53723-3
Short code
SLC26A4 p.L236P Bld Ql
Synonyms
SLC26A4 p.L236P Bld Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
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

What Is Creatinine?

Creatinine is a byproduct of muscle breakdown and is naturally produced in your body. It circulates in your blood and is removed by your kidneys. Elevated levels may suggest kidney function issues or other health concerns.

Why Is This Test Done?

Doctors order creatinine tests to evaluate kidney health, monitor chronic conditions like diabetes or heart disease, or check for signs of kidney damage before certain procedures.

What to Expect Before the Test

No special preparation is needed. You may have a blood draw from a vein in your arm. If you’re on a low-protein diet, discuss it with your doctor beforehand, as it may affect results.

What the Results Mean

Results help determine how well your kidneys are working. Higher-than-normal levels may indicate reduced kidney function, while lower levels could suggest dehydration or muscle loss.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine

Frequently asked questions

How does creatinine relate to kidney health?
Creatinine is a key marker for kidney function because it reflects how efficiently your kidneys filter waste. Consistently high levels may signal kidney disease, while sudden spikes could indicate dehydration, severe muscle injury, or other conditions requiring further evaluation.
What if my creatinine level is high?
A high creatinine level may prompt your doctor to investigate kidney function further, including additional tests or adjustments to your medications. Lifestyle changes like staying hydrated or managing conditions like diabetes can sometimes help.
Can diet affect creatinine levels?
Yes, high-protein diets can temporarily raise creatinine levels, as more muscle breakdown occurs. Your doctor may recommend monitoring or adjusting your diet 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