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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 produced by the liver in response to inflammation or infection in your body.

Quick summary

["CRP helps doctors track inflammation, often used to check for infections or other health issues."]

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

Key facts at a glance

LOINC
43529-7
Short code
XR Orbit+Face Views
Synonyms
XR Orbit+Face Views
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
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 a CRP test to monitor inflammation, diagnose conditions like infections (e.g., pneumonia, urinary tract infections), or assess risks for diseases like heart disease or autoimmune disorders. It can also help evaluate how well treatment is working for conditions causing chronic inflammation.

What to Expect Before the Test

No special preparation is usually needed. If you’re having blood drawn, you may want to drink water beforehand to help reduce discomfort. Avoid smoking or consuming caffeine for 30 minutes before the test if instructed.

What Happens During the Test?

A small needle is inserted into a vein, typically in your arm, to draw a blood sample. The process is quick and usually painless. The blood is then sent to a lab for analysis using nephelometry, a method that measures how much light a protein scatters.

What Are Possible Results?

Results are reported in milligrams per deciliter (mg/dL). Higher than normal levels may indicate inflammation, infection, or other health concerns. Your doctor will interpret the 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 (Nephelometry)

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 and healthcare provider. Follow-up instructions from your doctor will guide you on when to expect them.
Can food or medications affect my CRP test results?
Generally, diet or common medications (like NSAIDs for pain) don’t significantly affect CRP levels. However, if you’re taking anti-inflammatory drugs, your doctor may advise timing your test around when you’re not taking them to get an accurate reading.
Is a CRP test the same as a complete blood count (CBC) or other blood tests?
No, CRP is a specific protein test that measures inflammation, while a CBC checks for red/white blood cells and platelets. Other tests (like ESR or ferritin) may also assess inflammation but are measured differently.
  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