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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 depends on this simple blood test."]

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

Key facts at a glance

LOINC
40930-0
Short code
PYGM p.R50X+G205S Bld/T Ql
Synonyms
PYGM p.R50X+G205S Bld/T Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Is Creatinine?

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

Why Is This Test Done?

Doctors order creatinine tests to check kidney health, monitor chronic conditions like diabetes or heart disease, or evaluate dehydration. It’s often used alongside other kidney function tests.

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, but exact values depend on factors like age, sex, and muscle mass. High levels may signal kidney issues, while very low levels might need further investigation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Creatinine levels are a key marker for kidney function. Elevated levels often indicate reduced kidney filtration, which can lead to waste buildup or fluid imbalance. Doctors may use these results to adjust medications, manage chronic kidney disease, or assess treatment plans for conditions like heart failure or diabetes.

Short name

None

Frequently asked questions

What causes creatinine levels to be higher than normal?
Higher-than-normal creatinine levels can result from kidney disease, dehydration, severe muscle breakdown (e.g., from injury or illness), or certain medications. High protein intake in diet may also temporarily affect levels.
What causes creatinine levels to be lower than normal?
Low creatinine levels may occur with dehydration, muscle wasting (e.g., from malnutrition or illness), or certain genetic conditions. Very low levels are less common and may warrant further evaluation.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status. Regular monitoring may be recommended if you have kidney disease, diabetes, heart conditions, or other risk factors.
  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