Skip to content

C-reactive protein (CRP) with withdrawal time endpoint for serum/plasma

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

This test measures the level of C-reactive protein, a protein produced by the liver in response to inflammation in your body.

Quick summary

["CRP helps your doctor assess inflammation, which can be linked to infections, injuries, or other health conditions."]

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

Key facts at a glance

LOINC
111875-1
Short code
Withdrawal time Endscpy
Synonyms
Withdrawal time Endscpy
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
7
Ref high
56
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
endoscopy
CPT
84484
SNOMED
302773008
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 Might Be Ordered

Your healthcare provider may order this test to monitor inflammation, check for infections, evaluate autoimmune conditions, or assess response to treatment. It’s often used alongside other tests to get a fuller picture of your health.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for a few hours before the blood draw if instructed. Avoid strenuous activity or taking certain medications that could affect inflammation levels.

How the Test Works

A small amount of blood is drawn from a vein in your arm. The blood sample is then processed to separate serum or plasma, where the CRP protein is measured using a sensitive detection method.

What the Results Mean

Higher CRP levels often indicate inflammation, which can signal infections, injuries, or conditions like arthritis. Lower levels suggest minimal inflammation. Your results will be compared to a reference range provided by your lab.

Reference range

Adult males: 7-56 U/L; Adult females: 7-43 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

What does CRP measure?
CRP measures the concentration of C-reactive protein in your blood. It’s an acute-phase reactant that rises in response to inflammatory processes, helping identify areas of concern like infections, tissue damage, or chronic inflammatory diseases.
Can CRP levels change with diet or exercise?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. While not as directly affected as some other biomarkers, reducing inflammation through healthy habits may lower CRP over time.
Is CRP the only test to check for inflammation?
No. CRP is one tool, but doctors may use other tests like ESR (erythrocyte sedimentation rate) or blood tests for different markers to get a comprehensive view of inflammation and overall health.
  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