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Plasma or Serum 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 and waste removal depend on this test."]

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

Key facts at a glance

LOINC
26991-0
Short code
PPA Mlk-mCnc
Synonyms
PPA Mlk-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 problems, monitor kidney disease, or evaluate how well your kidneys are working after treatment for conditions like high blood pressure or diabetes. It can also help determine if you need dialysis or other kidney support.

What to Expect Before the Test

You may need to fast for 8–12 hours before the test if instructed, but this is not always required. Bring any medications you’re taking, as some (like NSAIDs) can affect results. Avoid strenuous activity the day before.

How the Test Is Done

A healthcare provider will draw blood from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause discomfort. The blood sample is sent to a lab for analysis.

What the Results Mean

Higher-than-normal levels may suggest kidney issues, dehydration, or muscle problems. Lower-than-normal levels could indicate overhydration or liver/kidney disease. Your doctor will interpret results in relation to your health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Creatinine Level

Frequently asked questions

How often should I get this test?
Your doctor will decide based on your medical history and needs. Regular tests may be scheduled if you have chronic kidney disease, diabetes, or high blood pressure.
Can diet affect this test?
Yes—eating large amounts of meat or protein-rich foods before the test can temporarily raise creatinine levels. Avoiding these foods for a day or two before testing may give more accurate results.
What if my results are abnormal?
If your results are outside expected ranges, your doctor will discuss next steps, which may include more tests, lifestyle changes, or treatment adjustments to support kidney health.
  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