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Serum or plasma **creatinine** concentration (mass concentration)

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

This test measures how well your kidneys are filtering waste products, specifically creatinine, a byproduct of muscle metabolism.

Quick summary

["Creatinine helps assess kidney function and detect early kidney problems."]

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

Key facts at a glance

LOINC
10072-7
Short code
S' wave dur L-AVR
Synonyms
S' wave dur L-AVR
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 Is This Test Done?

Your doctor may order this test to check for kidney disease, monitor kidney function over time, or evaluate symptoms like swelling, fatigue, or changes in urine output. It’s often used alongside other tests to diagnose conditions like chronic kidney disease or acute kidney injury.

What to Expect Before the Test

No special preparation is needed. If you’re having blood drawn, you may feel a slight pinch, but it’s usually over quickly. If urine is involved, you’ll collect a sample in a clean container at home or during a clinic visit.

What the Test Results Mean

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

Common Conditions This Test Helps Identify

This test helps identify kidney disease, including chronic kidney disease (CKD), acute kidney injury, or conditions like diabetes or heart disease that can affect kidney function.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Creatinine levels are a key marker for kidney function because it’s directly related to how well blood is filtered. Elevated levels often signal reduced kidney function, while persistently low levels may warrant further investigation to rule out other causes like dehydration or muscle disorders.

Short name

Creatinine Level

Frequently asked questions

Why might my creatinine level be higher than expected?
Several factors can influence creatinine levels, including muscle mass, dehydration, certain medications, or kidney disease. Your doctor will review your results alongside other health factors to determine the cause.
Can diet affect my creatinine test results?
Dietary changes like eating more protein or consuming less water can temporarily affect creatinine levels. However, your doctor will consider your overall diet and lifestyle when interpreting results.
Is there anything I should avoid before the test?
No specific restrictions apply, but inform your doctor about any medications or supplements you’re taking, as they may influence results.
  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