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Serum or Plasma Creatinine Concentration (Substance 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 check—high levels may signal kidney problems."]

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

Key facts at a glance

LOINC
73944-1
Short code
MAM-2201 Bld Ql
Synonyms
MAM-2201 Bld Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

Why This Test Matters

Creatinine is a byproduct of muscle breakdown and is normally filtered out by your kidneys. If your kidneys aren’t working well, creatinine builds up in your blood. This test helps doctors monitor kidney health, especially in people with diabetes, high blood pressure, or other conditions that may affect the kidneys.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a larger blood draw. 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. You may feel a small pinch, but it usually takes only a few minutes. The blood is then sent to a lab for testing.

What the Results Mean

Results are compared to a general reference range, which can vary slightly by lab. High levels may indicate kidney disease, while very low levels could suggest muscle loss or liver problems. Your doctor will discuss your specific results with you.

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 may order this test regularly if you have kidney disease, diabetes, or high blood pressure. Others may get it once or twice a year if they’re at higher risk. Follow your healthcare provider’s recommendations.
Can diet affect my creatinine levels?
Dietary changes alone won’t change creatinine levels, but dehydration can raise them. Staying hydrated is important, but avoid excessive protein intake unless your doctor advises it.
What if my results are outside the normal range?
If your results are high, your doctor may recommend further tests to check kidney function. If low, they might investigate other conditions like muscle wasting or liver issues. Always discuss your results with your 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