Skip to content

C-reactive protein (CRP) by nephelometry

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

This test measures the level of C-reactive protein in your blood, a marker often checked for signs of inflammation or infection.

Quick summary

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

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

Key facts at a glance

LOINC
6290-1
Short code
MCP C3b-C4b WBC Ql
Synonyms
MCP C3b-C4b WBC Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.5
Ref high
11
Critical range
2 N/A – 30 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85004
SNOMED
900000000000003002
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 CRP testing to monitor conditions such as rheumatoid arthritis, heart disease, or infections. It can also help track how well treatments are working or detect early signs of inflammation in your body.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

CRP levels can vary based on health status, age, and other factors. Higher levels may indicate inflammation, but they don’t always pinpoint the cause. Your provider will discuss results with you in the context of your overall health.

Common Conditions Monitored

CRP is commonly used to monitor conditions like inflammatory diseases (e.g., lupus, arthritis), infections, or to evaluate heart health. It’s also sometimes checked after surgery or injury to track healing.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Neph)

Frequently asked questions

What does a high CRP level mean?
A high CRP level often means your body is responding to inflammation or infection. It doesn’t always point to a specific problem, so your provider will review the results with you and may order additional tests.
How often should I get this test?
Your provider will determine how often you need CRP testing based on your health needs. Some people get it yearly, while others may need it more frequently if they have ongoing conditions like arthritis or heart disease.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a balanced diet, staying active, and managing stress may help lower inflammation 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