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Serum or Plasma Creatinine Concentration (Substance Concentration)

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of creatinine, a waste product from muscle breakdown, in your blood or plasma. It helps assess how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney function and detect early kidney problems."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
7283-5
Short code
Yellow Dock BasoBnd Ab Qn
Synonyms
Yellow Dock BasoBnd Ab Qn
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
lhr
CPT
82553
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors may order a creatinine test to monitor kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output. It’s also used before certain procedures or medications to ensure your kidneys are functioning properly.

What to Expect Before the Test

No special preparation is needed unless instructed by your healthcare provider. You may have a blood draw (serum/plasma) or a urine sample collected, depending on the test type. If you’re on a low-protein diet, discuss it with your doctor before testing.

What the Results Mean

Creatinine levels can vary based on muscle mass, hydration status, and other factors. High levels may indicate kidney problems, while very low levels could suggest muscle loss or dehydration. Your doctor will interpret results in relation to your overall health.

Common Causes of Abnormal Results

Elevated creatinine levels can result from kidney disease, dehydration, or conditions that reduce blood flow to the kidneys. Low levels may occur with severe muscle wasting or overhydration. Other factors like certain medications or illnesses can also affect results.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: whole-blood

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine Level

Frequently asked questions

How often do I need this test?
Your doctor will determine how often you need this test based on your health history, symptoms, and treatment plan. Some people may need it yearly, while others may require more frequent checks, especially if they have kidney-related conditions.
What should I do if my creatinine level is high?
If your test results show elevated creatinine, your doctor may recommend lifestyle changes (like staying hydrated or adjusting diet), medications, or further testing to identify the cause and manage it effectively. Follow their advice closely.
Can diet affect creatinine levels?
Yes, diet can influence creatinine levels. High-protein foods or dehydration may temporarily raise levels, while proper hydration helps maintain normal kidney function. Always discuss dietary changes with your healthcare provider before making significant adjustments.
  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 17, 2026. · Read our editorial policy