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Serum Creatinine (Creatinine Level)

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

["Kidney function is evaluated by checking creatinine levels."]

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

Key facts at a glance

LOINC
25186-8
Short code
PZA Islt Slgr Mcbct AB 25.0
Synonyms
PZA Islt Slgr Mcbct AB 25.0
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
method-for-slow-growing-mycobacteria-antibiotic-concentration-at-ug-ml
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 is a byproduct of muscle breakdown and is naturally filtered out by your kidneys. High levels can indicate kidney problems, while low levels might suggest overhydration or muscle wasting. This test is often used alongside other measures, like blood urea nitrogen (BUN), to diagnose and monitor kidney disease.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on a low-protein diet or have recently exercised intensely, let your healthcare provider know—these factors can temporarily affect creatinine levels.

Common Causes of Abnormal Results

Elevated creatinine levels may signal reduced kidney function, dehydration, or conditions like muscle damage or heart failure. Low levels could mean you’re drinking too much fluid or have very little muscle mass. Your doctor will consider your overall health and other test results when interpreting the results.

What the Results Mean

Your results will be compared to a reference range provided by your lab. While ranges can vary slightly by lab, they’re used as a general guideline to help identify potential issues. Your doctor will discuss the results in the context of your medical history and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

None

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. Others may get it less often, depending on their health status. Regular check-ups are the best way to know when to schedule it.
Can diet affect my creatinine levels?
Yes, diet can influence creatinine levels. High-protein foods may temporarily increase levels, while dehydration can raise them. Alcohol and certain medications can also affect kidney function. Always follow your doctor’s advice about diet and supplements.
Is there anything I should avoid before the test?
Avoid excessive alcohol or high-protein meals 24 hours before the test. Stay hydrated unless instructed otherwise, as dehydration can raise creatinine levels. Let your doctor know about any medications or supplements you’re taking, as they may impact 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