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C-reactive protein (CRP) by nephelometry (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.

Quick summary

["CRP helps doctors assess inflammation, often used to monitor conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
13226-6
Short code
CMV IgM CSF-aCnc
Synonyms
CMV IgM CSF-aCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate responses to treatments. It can also help diagnose infections or identify risks for conditions like heart disease or certain cancers.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a larger blood panel. Wear comfortable clothing and plan to stay for about 15 minutes while blood is drawn.

How the Test Works

A healthcare professional will draw blood from a vein in your arm. The blood sample is then sent to a lab, where it is analyzed using nephelometry—a method that measures how much light scatters when proteins interact with a laser.

What the Results Mean

Results are typically reported in milligrams per deciliter (mg/dL). Higher levels may indicate inflammation, infection, or other health issues, while lower levels may suggest no active inflammation. Your doctor will interpret results in the context of your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP Plasma

Frequently asked questions

What does a high CRP level mean?
A high CRP level often signals inflammation in your body, which can be caused by infections (like pneumonia or urinary tract infections), autoimmune diseases (such as rheumatoid arthritis), or conditions like heart disease or cancer. It’s a general marker, not specific to one condition, so doctors use it alongside other tests and symptoms to guide diagnosis.
What does a low CRP level mean?
A low CRP level usually means there is little to no active inflammation in your body. However, it doesn’t rule out conditions like chronic diseases or latent infections. Your doctor may still recommend follow-up tests or ongoing monitoring if you have a known condition.
Can CRP levels change over time?
Yes, CRP levels can fluctuate based on your health status, recent infections, medications, or even stress. If your levels are elevated, your doctor may retest after a few weeks to see if the inflammation improves with treatment or lifestyle changes.
  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