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Serum Creatinine (from whole blood)

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 depends on this test—high levels may signal kidney problems."]

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

Key facts at a glance

LOINC
85372-1
Short code
Neut.fMLP DHR/Neut fMLP NFr Cont Bld FC
Synonyms
Neut.fMLP DHR/Neut fMLP NFr Cont Bld FC
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why It’s Done

Your doctor may order this test to check for kidney disease, monitor kidney function before or after treatment, or evaluate symptoms like swelling, fatigue, or changes in urine output. It’s also used to guide medications that affect kidney function.

What to Expect

A small blood sample is taken from a vein, usually in your arm. You may feel a brief pinch, but it’s quick. No special preparation is needed unless instructed otherwise.

Normal vs. Abnormal Results

While reference ranges vary by lab, higher-than-expected levels may indicate reduced kidney function, while lower levels could suggest dehydration or muscle loss. Your doctor will interpret results in the context of your health.

Common Causes of Changes

Factors like dehydration, muscle damage, or certain medications can temporarily raise creatinine levels. Chronic kidney disease, diabetes, or heart conditions may also affect it over time.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

How long will results take to return?
Results are typically available within 1–3 business days, depending on your lab. Follow-up with your doctor if you have questions about timing or next steps.
What if my results are out of range?
If your creatinine level is higher than expected, your doctor may recommend further tests (like urine tests) or adjustments to your treatment plan. If lower, they may check for conditions like malnutrition or dehydration.
Can I eat or drink before this test?
No special diet is needed, but avoid excessive alcohol or large amounts of protein-rich foods 24 hours before testing, as they may affect 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