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Serum or Plasma Creatinine Concentration (Quantitative)

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

["A creatinine test helps check kidney function by measuring waste in your blood."]

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

Key facts at a glance

LOINC
2501-5
Short code
UIBC SerPl-mCnc
Synonyms
UIBC 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 Matters

Your kidneys normally filter waste products like creatinine from your blood. High levels may indicate impaired kidney function or disease, while low levels could suggest muscle breakdown or other conditions. This test is often used alongside other kidney function tests to monitor overall 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 dilute creatinine levels if needed. Avoid strenuous exercise or heavy meals that day.

How the Test Is Done

A healthcare provider will draw blood from a vein in your arm. The sample is sent to a lab for analysis. If a urine sample is used, you’ll collect a midstream urine specimen in a clean container.

What the Results Mean

Results are compared to a reference range based on age, sex, and overall health. Elevated levels may signal kidney problems, while very low levels could require further investigation for conditions like muscle atrophy or liver disease.

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 recommend this test periodically if you have a history of kidney disease, diabetes, high blood pressure, or other conditions that affect kidney function. Regular monitoring helps track changes over time and adjust treatments as needed.
What causes creatinine levels to be too high?
High creatinine levels can result from kidney disease, dehydration, severe muscle damage, or conditions that reduce blood flow to the kidneys. Chronic kidney disease, diabetes, or heart failure are common causes.
Can diet affect creatinine levels?
Dietary changes alone won’t significantly alter creatinine levels, but eating a high-protein diet may temporarily increase muscle breakdown, which could slightly raise levels. Hydration is key—drinking enough water helps maintain normal 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