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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 in your body.

Quick summary

["CRP helps identify inflammation, often used to monitor conditions like infections, autoimmune diseases, or after surgery."]

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

Key facts at a glance

LOINC
90422-7
Short code
TACI cells/Cells.CD19 NFr Bld
Synonyms
TACI cells/Cells.CD19 NFr Bld
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
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 treatment. It can also help diagnose infections or assess risks for conditions like heart disease.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast before the test if it’s part of a broader blood panel, but CRP alone typically doesn’t require fasting.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood is then sent to a lab for analysis.

What Are the Possible Results?

Results are reported in milligrams per liter (mg/L). Higher than normal levels may suggest inflammation, infection, or other health issues. Your results will be interpreted by your provider based on your medical history and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Nephelometry)

Frequently asked questions

What Does a High CRP Level Mean?
A high CRP level may signal inflammation in your body, which could be due to infections, autoimmune diseases, or other health concerns. Your provider will discuss your results with you and may recommend additional tests or treatments based on the findings.
What Does a Low CRP Level Mean?
A low CRP level generally means there is less inflammation in your body. However, it doesn’t rule out all causes of inflammation, so your provider will consider other factors, including your symptoms and medical history, when interpreting the results.
Can CRP Levels Change Over Time?
Yes, CRP levels can fluctuate depending on your health status, recent infections, medications, or other conditions. If your CRP level is monitored over time, your provider may track changes to assess how your condition is progressing or responding to treatment.
  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