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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. It helps doctors assess whether inflammation is present and monitor conditions like infections, autoimmune diseases, or other inflammatory disorders.

Quick summary

["CRP helps track inflammation, guiding treatment decisions and monitoring recovery."]

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

Key facts at a glance

LOINC
27167-6
Short code
C trach IgM Titr CSF IF
Synonyms
C trach IgM Titr CSF IF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why CRP Matters in Your Health

CRP is a marker that signals your body’s immune response. High levels may indicate infections, injuries, or conditions like rheumatoid arthritis, lupus, or heart disease. Doctors use it to check for inflammation after surgery, during infections, or to evaluate chronic conditions like inflammatory bowel disease.

When This Test Is Ordered

Your doctor may order a CRP test if you have symptoms of inflammation (like fever, joint pain, or swelling), if you’re recovering from surgery or an illness, or if you have a chronic condition that affects inflammation. It’s also used to monitor treatment progress for certain diseases.

What to Expect Before the Test

No special preparation is usually needed, but your doctor might ask you to avoid certain medications (like nonsteroidal anti-inflammatory drugs) that could affect results. You may have blood drawn from a vein in your arm, similar to other blood tests.

What the Results Mean

Results are reported in milligrams per liter (mg/L). A higher CRP level often means more inflammation is present, while lower levels suggest reduced inflammation. Your doctor will interpret the results in the context of your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: How CRP Helps Doctors

Short name

CRP (Serum/Plasma)

Frequently asked questions

What does a high CRP level mean?
A high CRP level can signal inflammation caused by infections (like pneumonia or urinary tract infections), autoimmune diseases (like lupus or rheumatoid arthritis), or other conditions like heart disease or cancer. It’s not a definitive diagnosis but helps guide further testing or treatment.
Can CRP levels change with diet or exercise?
Diet and exercise can influence inflammation indirectly. For example, a healthy diet rich in fruits, vegetables, and omega-3s may help lower CRP levels over time, but results depend on overall health and medical conditions. Always discuss lifestyle changes with your doctor.
Is CRP the same as a white blood cell count?
No, CRP is a protein marker for inflammation, while a white blood cell count measures the number of immune cells in your blood. Both tests are used together to assess immune response, but they provide different information.
  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