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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 breakdown, in your blood to assess kidney function.

Quick summary

["Helps check how well your kidneys filter waste from your blood."]

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

Key facts at a glance

LOINC
28532-0
Short code
NOPURPOSEINLIFE
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
reported-living-hiv
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 This Test Is Done

Your doctor may order this test to evaluate kidney health, monitor chronic kidney disease, check for kidney damage, or assess overall kidney function before certain procedures. It’s also used to monitor conditions like heart failure, diabetes, or dehydration that can affect kidney function.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a broader metabolic panel. Avoid strenuous exercise or heavy meals 24 hours prior. Hydration can affect results, so drink as usual unless instructed otherwise.

How the Test Is Performed

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

What the Results Mean

Results are compared to a reference range specific to your age, sex, and overall health. Higher levels may indicate reduced kidney function, while lower levels could suggest muscle loss or other conditions. Your doctor will interpret results in the context of your medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated creatinine levels often signal impaired kidney function, as the kidneys normally filter waste products like creatinine from the blood. Chronic kidney disease, dehydration, or severe muscle disorders can raise levels. Low levels may reflect malnutrition or muscle atrophy, but they’re less common. Regular monitoring helps detect kidney issues early.

Short name

Creatinine

Frequently asked questions

What causes creatinine levels to be higher than usual?
Higher-than-normal creatinine levels may result from kidney disease, dehydration, severe muscle damage, heart failure, or certain medications. Conditions like diabetes or high blood pressure can also contribute if kidneys are stressed over time.
Can diet affect creatinine test results?
Dietary changes like high-protein intake may temporarily raise creatinine levels, but they don’t alter the test’s diagnostic value. Your doctor may adjust interpretation if you have a known dietary pattern affecting muscle protein.
How often should I get this test?
Frequency depends on your health. People with kidney disease or risk factors (e.g., diabetes, hypertension) may need it monthly or quarterly. Others may get it once or twice a year, as recommended by their doctor.
  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