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Serum or Plasma 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 or plasma. It helps assess how well your kidneys are filtering blood.

Quick summary

["Kidney function depends on this test to detect early kidney problems."]

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

Key facts at a glance

LOINC
11914-9
Short code
GA from CRL.Robinson75
Synonyms
GA from CRL.Robinson75
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-crl-robinson
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 Is This Test Done?

Your doctor may order this test to check for kidney disease, monitor kidney function over time, or evaluate symptoms like swelling, fatigue, or changes in urine output. It’s also used before certain procedures or medications that affect kidney health.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a broader kidney function panel. Drink plenty of water the day before to help your kidneys work normally.

What Happens During the Test?

A healthcare provider will draw blood from a vein in your arm. The sample is sent to a lab for analysis. If testing urine, you’ll collect a sample at home or in a clinic.

What Are Normal Results?

Results are compared to standard ranges, but your actual values will be provided by your lab report. High levels may signal kidney issues, while very low levels could indicate muscle disorders or other health problems.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

Why might my creatinine level be higher than expected?
Higher levels can result from dehydration, muscle breakdown (e.g., from injury or illness), or kidney disease. If you’ve been sick, exercised heavily, or had recent surgery, these factors could temporarily raise your result.
What if my creatinine level is lower than expected?
Lower levels may occur with muscle loss (e.g., from aging or malnutrition) or rare conditions affecting muscle metabolism. Your doctor may check for other causes, such as liver disease or certain medications.
How often should I get this test?
Your doctor will determine frequency based on your health. For kidney disease monitoring, tests may be done every 3–12 months. If you have no known issues, it’s often checked only when symptoms arise or during routine checkups.
  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