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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

["A creatinine test is a key part of kidney function checks."]

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

Key facts at a glance

LOINC
111014-7
Short code
ENA SM+RNP Ab Msmt Ser
Synonyms
ENA SM+RNP Ab Msmt Ser
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

Creatinine is a byproduct of muscle breakdown that your kidneys filter out of your blood. If your kidneys aren’t working properly, creatinine levels can rise. This test helps doctors check for kidney disease, monitor kidney function over time, or evaluate kidney damage from other conditions.

What to Expect Before the Test

You won’t need special preparation. If you’re having blood drawn, tell your healthcare provider if you’re on blood thinners or have a history of bleeding easily. For urine tests, you may need to collect a sample over 24 hours, so plan accordingly.

How the Test Works

Blood tests are drawn from a vein in your arm, while urine tests involve collecting a sample over a set period. The lab uses specialized equipment to measure creatinine levels accurately.

What the Results Mean

Results are compared to a general reference range, but your actual values may vary based on age, sex, muscle mass, and overall health. High levels may signal kidney problems, while low levels could indicate muscle loss or other conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine Level

Frequently asked questions

How often should I get this test?
Your doctor will determine how often you need this test based on your health history, symptoms, and any kidney-related conditions. Regular monitoring may be recommended if you have diabetes, high blood pressure, or a family history of kidney disease.
Can diet affect creatinine levels?
Dietary changes like eating more protein can temporarily raise creatinine levels, but it’s not a long-term solution. Focus on managing underlying health conditions, staying hydrated, and following your doctor’s advice.
What if my results are outside the normal range?
If your results are abnormal, your doctor will discuss next steps, which may include further testing, lifestyle changes, or treatment to address potential kidney issues. 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