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Serum Creatinine Concentration (Qualitative Endpoint)

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

This test measures the amount of creatinine, a waste product from muscle metabolism, in your serum to assess kidney function. It helps determine how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney health and diagnose kidney disease early."]

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

Key facts at a glance

LOINC
111864-5
Short code
Scope of observation Endscpy
Synonyms
Scope of observation Endscpy
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
endoscopy
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 metabolism that the kidneys filter out of your blood. High levels can indicate poor kidney function, while low levels may suggest overhydration or other conditions. This test is often used alongside other kidney function tests, like blood urea nitrogen (BUN), to evaluate kidney health comprehensively.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood sample drawn from a vein in your arm, similar to other blood tests. If you’re on a low-protein diet or have recently exercised, your doctor may advise you to wait a few days before testing to get more accurate results.

Common Causes of Abnormal Results

Elevated creatinine levels may suggest kidney disease, dehydration, or conditions that reduce blood flow to the kidneys. Low levels could indicate overhydration, muscle wasting, or certain liver or heart conditions. Always discuss your results with your healthcare provider, as they’ll consider your overall health and other tests.

When This Test Might Be Ordered

Your doctor may order this test if you have symptoms like fatigue, swelling, frequent urination, or changes in urine appearance. It’s also commonly used during routine check-ups, pregnancy, or before starting medications that can affect kidney function.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine (Qualitative)

Frequently asked questions

What does a high creatinine level mean?
A high creatinine level often signals reduced kidney function, meaning your kidneys aren’t filtering blood as well as they should. This can be an early sign of chronic kidney disease (CKD) or acute kidney injury (AKI). Your doctor will use this test along with other factors, like urine tests and blood pressure, to assess your kidney health.
What if my creatinine level is normal but I still feel unwell?
Even if your creatinine level is within normal limits, other conditions—such as dehydration, heart failure, or certain medications—can temporarily affect kidney function. If you’re experiencing symptoms like nausea, shortness of breath, or swelling, talk to your doctor to explore other possible causes.
Can diet affect creatinine levels?
Yes, diet can influence creatinine levels. High-protein diets may temporarily increase creatinine because your muscles produce more waste. Conversely, dehydration can raise creatinine levels, so staying well-hydrated is important. Your doctor may recommend dietary adjustments if needed, especially if you have kidney concerns.
  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