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Serum or Plasma Creatinine Concentration (Qualitative or Quantitative Assessment)

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 via waste product levels—critical for detecting early kidney issues."]

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

Key facts at a glance

LOINC
28529-6
Short code
STRENGTHFROMFAMILY
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
reported-living-hiv
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 levels are a key indicator of kidney function. Your kidneys filter waste products from your blood, and creatinine is one of the main byproducts of muscle breakdown. Abnormal levels can signal kidney problems, even before symptoms appear.

How the Test Works

A small blood sample is taken, and the lab analyzes it to measure creatinine concentration. Some tests may also include a qualitative check (yes/no presence) or a quantitative measurement (exact amount).

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications or foods that could affect results. Drink plenty of water the day before if your doctor suggests it.

Possible Results and Next Steps

Results may be reported as qualitative (positive/negative) or quantitative (specific concentration). If levels are unusually high, your doctor may recommend further kidney function tests or adjustments to your treatment plan.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Kidney Function and Health

Short name

Creatinine Level (Qualitative/Quantitative)

Frequently asked questions

What does a high creatinine level mean?
A high creatinine level may indicate reduced kidney function or kidney disease. It can also be influenced by factors like dehydration, muscle mass, or certain medications. Your doctor will consider the full clinical picture.
Can diet affect creatinine levels?
Diet alone rarely changes creatinine levels significantly, but dehydration can raise them. Eating a balanced diet rich in fruits and vegetables may support overall kidney health, but high-protein diets can temporarily increase creatinine levels.
How often should I get this test?
Your doctor will determine how often to check creatinine levels based on your health status, medications, and any kidney-related concerns. Regular monitoring may be needed if you have diabetes, high blood pressure, or a history of kidney issues.
  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