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C-reactive protein (CRP) by nephelometry (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 your body.

Quick summary

["CRP helps doctors assess inflammation, track infections, or monitor conditions like arthritis or heart disease."]

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

Key facts at a glance

LOINC
23700-8
Short code
CPV Ab Ser Ql IF
Synonyms
CPV Ab Ser Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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, infections, or other health conditions. It can also help monitor how your body is responding to treatment for conditions like arthritis, heart disease, or autoimmune disorders.

What Does a High or Low CRP Level Mean?

Elevated CRP levels often indicate inflammation or infection, but they can also be influenced by other factors like stress, smoking, or certain medications. Low levels may suggest no active inflammation, but they don’t rule out all causes.

Common Uses in Healthcare

CRP is commonly used to screen for conditions like rheumatoid arthritis, heart attacks, or sepsis. It can also help evaluate the effectiveness of treatments for chronic inflammatory diseases.

How Is the Test Performed?

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

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

What are the typical reference ranges for CRP?
Reference ranges can vary by lab and individual health status. Typically, low CRP levels (below 1 mg/L) suggest minimal inflammation, while higher levels (above 10 mg/L) may indicate more severe inflammation or infection. Values between these ranges are considered intermediate and may need further evaluation.
How long does it take to get results from this test?
Results are usually available within 24 to 48 hours, depending on the lab’s processing time and your healthcare provider’s request.
Can lifestyle changes affect CRP levels?
Yes, lifestyle factors such as diet, exercise, smoking, and stress can influence CRP levels. Reducing inflammation through healthy habits may help lower CRP levels over time.
  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