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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 serum (blood plasma). 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
13414-8
Short code
Serine Amn-mCnc
Synonyms
Serine Amn-mCnc
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why This Test Matters

Creatinine levels can indicate how efficiently your kidneys are working. High levels may suggest kidney damage or disease, while low levels could signal dehydration or muscle loss. This test is often used alongside other kidney function tests to diagnose and monitor conditions like chronic kidney disease.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into a vein in your arm, and a small amount of blood will be drawn. If you’re on a low-protein diet or have had recent muscle activity, let your healthcare provider know—these can affect results.

How the Test Works

Blood is collected and sent to a lab, where it’s analyzed to measure creatinine concentration. The test typically uses an enzymatic method to determine the amount of creatinine in your serum.

Possible Results and Next Steps

Results are compared to a reference range, but exact values can vary by lab. If your levels are outside the expected range, your doctor may recommend further testing or adjustments to your treatment plan, such as monitoring kidney function over time or evaluating medications that could impact kidney health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

What does a high creatinine level mean?
High creatinine levels often signal impaired kidney function, as the kidneys normally filter waste products like creatinine from your blood. Elevated levels may indicate kidney disease, dehydration, or conditions that reduce blood flow to the kidneys. Your doctor may use these results to guide treatment, such as adjusting medications or recommending lifestyle changes.
What does a low creatinine level mean?
Low creatinine levels can sometimes suggest dehydration, muscle wasting, or conditions that reduce muscle mass. However, very low levels may also be normal if your muscle mass is naturally low. Your doctor will consider other factors, such as your diet and overall health, when interpreting results.
Can diet or exercise affect this test?
Yes. High-protein diets or intense exercise can temporarily raise creatinine levels. Avoiding heavy meals or strenuous activity before the test can help ensure more accurate results. Always follow your healthcare provider’s instructions for optimal testing conditions.
  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