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C-reactive protein (CRP) by nephelometry

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

This test measures the level of C-reactive protein, a protein made by your liver that rises in response to inflammation or infection in your body.

Quick summary

["CRP helps doctors check for inflammation and track conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
93787-0
Short code
LCMV IgG+IgM CSF Ql
Synonyms
LCMV IgG+IgM CSF Ql
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 doctor may order CRP testing to monitor inflammation, diagnose conditions like infections (e.g., pneumonia), or assess whether treatments for conditions like arthritis or heart disease are working. It can also help check for signs of blood clots or other inflammatory disorders.

What Does a High CRP Level Mean?

A higher-than-normal CRP level often signals inflammation. For example, it may indicate an infection, an autoimmune condition, or a reaction to certain medications. However, CRP alone doesn’t diagnose a specific condition—your doctor will consider other symptoms and test results.

What Does a Low CRP Level Mean?

A low CRP level usually means there’s little to no inflammation in your body. This could be normal if you’re healthy, but it may also suggest that an infection or inflammatory condition is under control or absent.

How Is This Test Performed?

A blood sample is taken from a vein in your arm. The blood is then sent to a lab where it’s 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

Frequently asked questions

How long does it take to get my CRP test results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing schedule. Your doctor will contact you with the results once they’re ready.
Can I eat or drink before this test?
You can eat and drink normally before this test, as it doesn’t require fasting. However, always follow your doctor’s specific instructions for your appointment.
What are some common conditions that might lead to high CRP levels?
High CRP levels can be seen in infections (like pneumonia or urinary tract infections), autoimmune diseases (such as rheumatoid arthritis), heart disease, certain cancers, or after surgery or trauma. Always discuss your symptoms with your doctor to understand the possible causes.
  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