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Serum Creatinine (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 serum. It helps assess kidney function.

Quick summary

["A creatinine test helps doctors check how well your kidneys are filtering waste from your blood."]

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

Key facts at a glance

LOINC
2934-8
Short code
Serine CSF-mCnc
Synonyms
Serine CSF-mCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Matters

Creatinine is a byproduct of muscle breakdown and is normally filtered out by your kidneys. High levels can indicate kidney problems, while low levels may suggest dehydration or muscle loss. This test is often used alongside other kidney function tests to monitor overall kidney health.

What to Expect Before the Test

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

What the Results Mean

Results are typically reported in milligrams per deciliter (mg/dL). While exact reference ranges vary by lab, higher than expected levels may signal kidney issues, while very low levels could raise concerns about hydration or muscle metabolism.

Common Causes of Abnormal Results

Kidney disease (including chronic kidney disease or acute kidney injury) is the most common cause of elevated creatinine. Other factors include dehydration, severe muscle damage, heart failure, or certain medications. Low levels may occur with dehydration, malnutrition, or overhydration.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine (Serum)

Frequently asked questions

How often do I need this test?
Your doctor may recommend this test periodically if you have a history of kidney problems, diabetes, hypertension, or other conditions that affect kidney function. Regular monitoring helps track kidney health over time, especially if you’re on medications that can impact kidneys.
Can diet affect my creatinine levels?
Yes, diet can influence creatinine levels. High-protein diets may temporarily increase creatinine, while very low-protein diets can lower it. However, creatinine is primarily filtered by the kidneys, so diet changes alone won’t replace the need for this test unless advised by your doctor.
What if my creatinine level is unusually high?
If your creatinine level is elevated, your doctor may order additional tests to check kidney function further, such as blood urea nitrogen (BUN) or a 24-hour urine protein test. They may also review your medications, diet, or overall health to identify potential causes and guide treatment.
  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