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Serum Creatinine 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 how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney function by measuring waste product levels in your blood."]

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

Key facts at a glance

LOINC
80621-6
Short code
ZIKV NAb Titr CSF Nt
Synonyms
ZIKV NAb Titr CSF Nt
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
neut
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order this test to evaluate kidney health, monitor kidney disease progression, or check for dehydration, muscle disorders, or other conditions affecting kidney function. It’s often used alongside other tests like blood urea nitrogen (BUN) to assess kidney function together.

What Does a High or Low Level Mean?

High levels may indicate reduced kidney function or conditions like heart failure, muscle breakdown, or dehydration. Low levels could suggest overhydration, liver disease, or certain muscle-wasting conditions.

How Is This 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 concentration using a specialized method, often enzymatic or spectrophotometric techniques.

What Are Common Results and Next Steps?

Results are typically compared to reference ranges provided by your lab. If your levels are outside expected ranges, your doctor may recommend further testing or adjustments to your treatment plan, such as monitoring kidney function more closely or modifying medications that affect kidney health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine (Serum)

Frequently asked questions

What causes creatinine levels to be higher than normal?
Several factors can lead to higher creatinine levels, including dehydration, severe muscle damage or illness, heart failure, liver disease, or conditions that reduce kidney function, such as chronic kidney disease or acute kidney injury.
What causes creatinine levels to be lower than normal?
Lower-than-normal creatinine levels may occur with overhydration, liver disease (which affects muscle breakdown), or certain genetic conditions that alter muscle metabolism. Rarely, very low levels could indicate overuse of diuretics or other medications that affect fluid balance.
Do creatinine levels change with diet?
Yes, diet can influence creatinine levels indirectly. High-protein diets may temporarily increase muscle breakdown, leading to slightly higher creatinine levels, while very low-protein diets might lower them. However, creatinine is primarily filtered by the kidneys, so diet changes are usually temporary and less impactful than kidney function itself.
  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