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C-reactive protein (CRP) by chemiluminescent immunoassay (serum/plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures a protein produced by your liver in response to inflammation, often used to assess low-grade inflammation or infection.

Quick summary

["Helps track subtle inflammation that may not show up with other tests."]

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

Key facts at a glance

LOINC
72390-8
Short code
C lusitaniae DNA Vag Ql NAA+probe
Synonyms
C lusitaniae DNA Vag Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
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 It’s Done

Your doctor may order this test to monitor chronic conditions like heart disease, arthritis, or autoimmune disorders. It can also help check for signs of infection, especially when symptoms are mild or unclear. Some people get it as part of routine check-ups to assess overall health.

What to Expect

A small blood sample is drawn from your arm. The sample is sent to a lab where it’s analyzed using a sensitive immunoassay method. Results are usually ready within a few days.

What the Results Mean

Higher-than-normal levels may indicate inflammation, infection, or other health issues. Lower-than-normal levels might suggest reduced inflammation. However, results alone don’t diagnose a condition—they’re used alongside other information.

Common Causes of Abnormal Results

Elevated CRP can be caused by infections (like colds or urinary tract infections), injuries, or inflammatory diseases (like lupus or rheumatoid arthritis). It may also rise after surgery or during stress. Low CRP could mean your body is handling inflammation well, but it can also occur in certain health conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CRP (High Sensitivity)

Frequently asked questions

How often will I need this test?
Your doctor will determine how often you need this test based on your health status, symptoms, and treatment plan. Some people get it every few months to monitor chronic conditions, while others may only need it once.
Can I eat or drink before the test?
You can eat and drink normally before the test unless your doctor instructs otherwise. Fasting isn’t required for CRP testing.
What are the risks of having this test?
The main risk is a minor bruise, soreness, or slight swelling at the needle site. Rarely, there may be a reaction to the blood draw, but serious complications are uncommon.
  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