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Serum or Plasma Mass Concentration of Creatinine

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 kidney function.

Quick summary

["A creatinine test helps check how well your kidneys are filtering waste from your blood."]

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

Key facts at a glance

LOINC
3794-5
Short code
MTX 1-2W p SerPl-mCnc
Synonyms
MTX 1-2W p SerPl-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 This Test Is Done

Your doctor may order this test to monitor kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output. It’s also used before certain procedures, during pregnancy, or if you have conditions like diabetes or high blood pressure that can affect kidney function.

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 metabolic panel. Avoid strenuous activity or certain medications that could affect results. Bring a list of all medications you’re taking.

During the Test

A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but it’s usually over quickly. The test takes a few minutes, and you can resume normal activities afterward.

After the Test

You can return to your usual activities immediately. Apply gentle pressure to the site to stop any bleeding, and check for signs of infection (like redness or swelling). Avoid reusing the needle or bandage.

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?
The frequency depends on your health. If you have kidney disease, your doctor may recommend regular testing. Otherwise, it’s often done once or twice a year if you have risk factors like diabetes or high blood pressure.
Can diet affect my creatinine test results?
Yes, eating a high-protein diet or consuming large amounts of meat can temporarily raise creatinine levels. Avoiding excessive protein for a day or two before the test may help stabilize results. Always follow your doctor’s instructions.
What if my results are abnormal?
If your results are outside the expected range, your doctor will discuss next steps, which may include further testing, lifestyle changes, or treatment adjustments. Never interpret results alone—always consult your healthcare provider.
  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