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C-reactive protein, mass concentration (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 or infection in the body.

Quick summary

["CRP helps track inflammation, often used to monitor conditions like infections, autoimmune diseases, or post-surgery recovery."]

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

Key facts at a glance

LOINC
9705-5
Short code
C immitis IgA Ser-aCnc
Synonyms
C immitis IgA Ser-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 doctor may order this test to check for signs of inflammation, monitor chronic conditions like rheumatoid arthritis or lupus, or evaluate your response to treatment. It can also help diagnose infections, such as pneumonia or appendicitis, or assess risk for heart disease.

What Does a High or Low CRP Level Mean?

Elevated CRP levels often indicate inflammation or infection. Very high levels may suggest severe conditions like sepsis or certain cancers. Low levels can sometimes mean inflammation is under control, but they don’t always rule out infection or other issues.

How Is the Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to measure CRP levels using a sensitive detection method.

What Are Common Uses?

CRP is commonly used to guide treatment decisions, monitor disease activity, and assess risk for complications in conditions like heart disease, autoimmune disorders, or after surgery.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

How often should I expect this test?
The frequency depends on your health condition and treatment plan. Your doctor will let you know how often to get this test, such as monthly, quarterly, or as needed.
What do my CRP results mean in the context of my health?
Your results will be discussed with your doctor, who will consider your overall health, symptoms, and other test results. Elevated levels may signal inflammation that needs addressing, while normal levels don’t always mean no inflammation is present.
Can lifestyle changes affect CRP levels?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. Reducing inflammation through healthy habits may lower CRP, but results vary by individual.
  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