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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 serum. It helps assess how well your kidneys are filtering blood.

Quick summary

["Kidney function check: creatinine levels help determine if your kidneys are working properly."]

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

Key facts at a glance

LOINC
41157-9
Short code
C trach IgM Ser Ql
Synonyms
C trach IgM 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 Your Kidneys Matter

Your kidneys play a vital role in filtering waste and excess substances from your blood, including creatinine. When your kidneys struggle, they may not remove enough creatinine, which can build up in your blood and affect your health. High levels might signal kidney problems, while low levels could indicate dehydration or muscle breakdown.

What Normal Levels Mean (Generally)

While specific reference ranges vary by lab, creatinine levels are often used alongside other tests to assess kidney function. Your doctor will consider your overall health, age, and other test results to interpret your results.

How This Test Is Done

A small 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. Results are typically available within 24–48 hours.

What Your Results Could Indicate

Elevated creatinine levels may suggest kidney damage or disease, while persistently low levels could indicate conditions like dehydration or muscle atrophy. Your doctor will discuss your results in the context of your medical history and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine

Frequently asked questions

What causes high creatinine levels?
High creatinine levels can result from reduced kidney function, dehydration, muscle disorders, or certain medications. Chronic kidney disease, diabetes, or heart conditions may also contribute. Your doctor will evaluate other factors, like urine tests or blood pressure, to understand the cause.
What causes low creatinine levels?
Low creatinine levels might be due to dehydration, muscle loss (e.g., from malnutrition or illness), or rare genetic conditions. In some cases, it could indicate overhydration or errors in lab processing, so your doctor will review your full medical picture.
How often should I get this test?
Your doctor will recommend how often to check your creatinine levels based on your health status. Regular monitoring may be needed if you have kidney disease, diabetes, heart issues, or take medications that affect kidney function.
  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