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Serum or Plasma Creatinine Concentration (Qualitative or 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 kidney function.

Quick summary

["Kidney health depends on filtering waste like creatinine; abnormal levels may signal kidney issues."]

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

Key facts at a glance

LOINC
62258-9
Short code
ermA+ermC Islt/Spm Ql
Synonyms
ermA+ermC Islt/Spm Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
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 check if your kidneys are working properly. Common reasons include monitoring chronic kidney disease, evaluating symptoms like fatigue, swelling, or frequent urination, or assessing kidney function before certain procedures.

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 broader metabolic panel. Avoid strenuous activity or excessive protein intake on the day of testing.

What the Test Results Mean

Creatinine levels vary by age, sex, muscle mass, and overall health. Higher-than-normal levels may indicate reduced kidney function, while lower levels could suggest dehydration or overhydration. Your doctor will interpret results in the context of your medical history.

Common Causes of Abnormal Results

Elevated creatinine levels can result from kidney disease, dehydration, heart failure, or certain medications. Low levels may occur with overhydration, liver disease, or muscle wasting. Other factors, like recent exercise or diet, can temporarily affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine Level (Serum/Plasma)

Frequently asked questions

How often do I need this test?
Your doctor will determine how often you need this test based on your health status. For example, people with kidney disease may need it monthly or more frequently, while healthy individuals might only need it annually or as part of routine check-ups.
What if my results are out of the normal range?
If your results are outside the normal range, your doctor will discuss them with you. They may recommend further tests, adjustments to your treatment plan, or lifestyle changes to improve kidney function or address underlying conditions.
Can diet affect this test?
Yes, diet can influence creatinine levels. High-protein foods or dehydration can temporarily raise results, while adequate hydration may lower them. Your doctor may suggest dietary adjustments if needed, but avoid drastic changes without professional guidance.
  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