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C-reactive protein (CRP) concentration in serum/plasma

Published: August 9, 2026Updated: August 16, 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 doctors assess inflammation, often used to monitor conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
96323-1
Short code
K aerog DNA L resp NAA+non-prb-NCncRng
Synonyms
K aerog DNA L resp NAA+non-prb-NCncRng
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
non-probe-amp-tar
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 Is This Test Done?

Your healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions (such as arthritis or heart disease), or evaluate responses to treatments. It can also help identify infections or other inflammatory processes in your body.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into a vein in your arm to draw blood. If you’re concerned about needles, let your healthcare provider know so they can provide additional comfort measures.

What Happens During the Test?

A healthcare professional will clean the area where the needle will go and insert it into your vein. Blood will be collected into a tube. The process usually takes a few minutes and may cause a brief pinch or discomfort.

What to Expect After the Test

After the blood is drawn, the needle will be removed, and pressure will be applied to the site to stop any bleeding. You may feel a small bruise or soreness, but this should go away quickly. Avoid vigorous activity for a short time to prevent bruising.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CRP levels often indicate inflammation, which can be caused by infections, injuries, autoimmune diseases, or other health conditions. While CRP alone doesn’t diagnose a specific condition, it helps guide treatment decisions and monitor disease activity. Very high levels may signal severe inflammation or infection, while low levels may suggest reduced inflammation or a stable condition.

Short name

CRP (Serum/Plasma)

Frequently asked questions

How often is CRP tested?
CRP testing frequency depends on your medical condition and treatment plan. Some people may have it checked monthly, quarterly, or annually, while others may only need it if symptoms or test results suggest inflammation is present.
What does a high CRP level mean?
A high CRP level typically signals inflammation in your body. It doesn’t specify the cause, but it may indicate infections, autoimmune diseases (like rheumatoid arthritis), heart disease, or other inflammatory conditions. Your doctor will review your results alongside other tests and symptoms to determine the next steps.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a balanced diet rich in fruits, vegetables, and omega-3 fatty acids, staying physically active, and managing stress may help lower CRP levels and reduce inflammation.
  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