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Serum Creatinine (Creatinine Level)

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 check with a simple blood test.

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

Key facts at a glance

LOINC
64313-0
Short code
FULLTIMEDIETITIANSTAFFPOSITIONSVACANTATENDOFPERIOD
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Do I Need This Test?

Your doctor may order this test to check for kidney problems, monitor kidney health over time, or evaluate how well your kidneys are working after treatment for conditions like heart disease or high blood pressure. It can also help determine if you need dialysis or other kidney support.

What Does a High or Low Level Mean?

High levels may indicate kidney disease, dehydration, or conditions that reduce blood flow to the kidneys. Low levels might suggest muscle breakdown, liver disease, or certain medications. Your doctor will interpret results in relation to your overall health.

How Is This Test Done?

A small blood sample is taken from a vein, usually in your arm. The sample is sent to a lab to measure creatinine levels. Results are typically available within a few days.

What Can Affect My Results?

Factors like muscle mass, hydration status, diet (especially protein intake), and certain medications can influence creatinine levels. Recent exercise, dehydration, or eating high-protein foods before the test may temporarily change results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for diagnosing and monitoring kidney function. Elevated levels often signal impaired kidney function, prompting further evaluation or treatment adjustments. Low levels may warrant investigation into underlying conditions affecting muscle or liver health.

Short name

None

Frequently asked questions

How often should I get this test?
Your doctor will determine the frequency based on your health condition. For example, people with kidney disease may need tests more often than others.
What are the typical reference ranges for this test?
Reference ranges can vary by lab and individual health. Your doctor will provide your specific results and compare them to your baseline or expected values.
Can I eat or drink anything before this test?
No special preparation is usually needed, but follow your doctor’s instructions. Avoid excessive protein intake or dehydration before testing.
  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