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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 via blood waste product levels."]

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

Key facts at a glance

LOINC
44990-0
Short code
C trach D+K IgA Ser Ql
Synonyms
C trach D+K IgA Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 Is This Test Done?

Your doctor may order this test to check for kidney problems, monitor kidney function over time, or evaluate conditions affecting kidney health, such as diabetes or high blood pressure. It’s also used before certain procedures to ensure your kidneys are working properly.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood, similar to other routine blood tests. If you’re on a low-protein diet, your doctor may advise against it for a few days before testing.

What Happens During the Test?

A healthcare professional will clean your arm with an antiseptic, insert a needle into a vein, and collect a small amount of blood into a test tube. The process usually takes a few minutes, and you may feel a brief pinch. The blood sample is then sent to a lab for analysis.

What Are the Results Mean?

Higher than expected levels may indicate poor kidney function, while lower levels could suggest muscle disorders or other health issues. Your doctor will interpret the results in the context of your overall health and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

What causes creatinine levels to change?
Creatinine levels can rise due to kidney disease, dehydration, severe muscle injury, or certain medications. They may also drop if you have a low-protein diet, liver disease, or certain genetic conditions affecting muscle metabolism.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status. For example, people with kidney disease may need it monthly or more frequently, while healthy individuals might only need it once a year or less.
Can diet affect creatinine levels?
Yes, diet can influence creatinine levels. Eating a high-protein diet may temporarily increase levels, while low-protein diets can lower them. 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