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Serum or Plasma Creatinine Concentration (Standard Method)

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 removal efficiency."]

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

Key facts at a glance

LOINC
5143-3
Short code
ECV4 Ab Titr Ser CF
Synonyms
ECV4 Ab Titr Ser CF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
comp-fix
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 poor kidney function, while low levels could suggest overhydration or muscle breakdown. This test is often used alongside other kidney function tests to monitor conditions like diabetes, heart disease, or chronic kidney disease.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before a blood test. For a urine test, you might be instructed to collect a sample over 24 hours. Hydration can affect results, so avoid excessive fluids unless directed otherwise.

Common Conditions Monitored

This test is commonly used to diagnose or monitor kidney disease, evaluate dehydration or fluid overload, assess muscle disorders, or check for conditions like chronic kidney disease, acute kidney injury, or metabolic disorders.

What Results Mean

Results are typically compared to your baseline or reference ranges provided by your healthcare provider. Elevated levels may signal kidney problems, while persistently low levels may warrant further investigation into hydration status or muscle health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine

Frequently asked questions

How often do I need this test?
The frequency depends on your health condition. For example, people with diabetes or kidney disease may need it every few months, while healthy individuals may only need it occasionally or as part of routine check-ups.
Can diet or exercise affect my creatinine levels?
Yes, diet high in protein or muscle activity can temporarily raise creatinine levels. Avoiding excessive protein intake for a day or two before testing may help stabilize results, but always follow your provider’s instructions.
What if my test results are abnormal?
If results are outside expected ranges, your doctor may recommend further tests, adjustments to medications, or lifestyle changes. They’ll discuss next steps based on your overall health and symptoms.
  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