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Serum or plasma concentration of C-reactive protein (CRP) measured by nephelometry

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

This test measures the amount of C-reactive protein in your blood. CRP is a protein produced by your liver in response to inflammation or infection.

Quick summary

["CRP helps doctors assess inflammation, infection, or risk of future health issues like heart disease."]

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

Key facts at a glance

LOINC
10241-8
Short code
O2 Ct CS-sCnc
Synonyms
O2 Ct CS-sCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

What Is CRP Used For?

CRP is often checked to monitor conditions like infections (e.g., pneumonia, urinary tract infections), inflammatory diseases (e.g., rheumatoid arthritis), or to evaluate risk for heart problems. It may also be used to track how well treatment is working for certain conditions.

Why Might You Need This Test?

Your doctor may order CRP testing if you have symptoms of inflammation, a suspected infection, or if you’re at higher risk for heart disease. It can also be part of routine check-ups for certain health conditions.

How Is the Test Done?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where CRP levels are measured using a specialized instrument that detects protein levels in the blood.

What Are Common Results?

Results are typically reported in milligrams per liter (mg/L). Higher than normal levels may indicate inflammation, infection, or other health concerns. Your doctor will interpret the results in relation to your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP Level

Frequently asked questions

What does a high CRP level mean?
A high CRP level often means your body is fighting inflammation or infection. This could be due to an acute illness, chronic condition like arthritis, or even a response to injury. Your doctor will discuss what this means for your specific situation.
Can CRP levels change with diet or exercise?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a heart-healthy diet, staying active, and managing stress may help lower CRP levels over time, but results can vary by individual.
How often should I get this test?
Your doctor will determine how often you need CRP testing based on your health needs. This could be once, as part of a routine check-up, or more frequently if you have a chronic condition like heart disease or arthritis.
  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