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Serum Creatinine Concentration (Mass Concentration)

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 kidney function.

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
82658-6
Short code
GAD Ab CSF Ql IF
Synonyms
GAD Ab CSF Ql IF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What Is Creatinine?

Creatinine is a byproduct of muscle breakdown that your kidneys normally filter out of your blood. High levels can indicate kidney problems, while low levels may suggest dehydration or other conditions.

Why Is This Test Done?

Doctors order creatinine tests to monitor kidney health, especially in people with diabetes, high blood pressure, or a history of kidney disease. It’s also used to assess how well your kidneys are working after treatments like chemotherapy or surgery.

How Is the Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to measure creatinine levels.

What Do Results Mean?

Results are compared to a general reference range to identify if levels are too high or too low. High creatinine may signal impaired kidney function, while very low levels might need further investigation for causes like dehydration or muscle disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Creatinine levels are a key indicator of kidney function. Elevated levels often suggest reduced kidney ability to filter waste, which can lead to long-term health risks like fluid buildup, electrolyte imbalances, or even kidney failure if untreated. Low levels may require additional evaluation to rule out conditions like dehydration or muscle wasting.

Short name

Creatinine

Frequently asked questions

What causes creatinine levels to change?
Creatinine levels can rise due to kidney disease, dehydration, muscle damage, or certain medications. They may drop if you’re dehydrated, have low muscle mass, or take supplements that affect kidney function.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status. Regular monitoring is common for people with chronic kidney disease, diabetes, or high blood pressure.
Can diet or exercise affect creatinine levels?
Diet high in protein can temporarily raise creatinine levels, but your doctor will consider overall health when interpreting results. Exercise itself doesn’t change creatinine levels but may indirectly affect kidney function if overdone or in people with pre-existing conditions.
  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