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Serum or plasma concentration of creatinine

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

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood or urine. It helps assess kidney function.

Quick summary

["Creatinine levels help 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
71575-5
Short code
ECG NEMSIS
Synonyms
ECG NEMSIS
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nemsis
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 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 diagnose and monitor conditions like chronic kidney disease.

What to Expect Before the Test

For blood tests, you may have a small needle inserted into your arm or vein. For urine tests, you’ll collect a sample in a container. Avoid strenuous activity or heavy meals 12 hours before a blood test to ensure accurate results. If you’re on a special diet (like low-protein), follow your doctor’s instructions.

Common Causes of Abnormal Results

Elevated creatinine levels may signal kidney issues, dehydration, or muscle disorders. Low levels could result from dehydration, muscle wasting, or certain medications. Always discuss your results with your healthcare provider, as they’ll consider your full medical history and other test results.

What to Do If You Have Questions

If you’re unsure about your test results or symptoms, contact your healthcare provider. They can explain what your creatinine levels mean in the context of your health and recommend next steps if needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

How long does it take to get my test results back?
Results are typically available within 1–3 business days, depending on your lab. Follow-up with your doctor to discuss findings and next steps.
Can I eat or drink before this test?
For blood tests, avoid heavy meals or fluids 8–12 hours beforehand. For urine tests, follow your doctor’s specific instructions, often involving a 24-hour collection or random sample.
What if my creatinine level is higher than expected?
If your results are elevated, your doctor may check for kidney disease, dehydration, or other conditions. They’ll review your medical history and other tests to determine the cause and next actions.
  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