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C-reactive protein (CRP) measured by nephelometry (plasma)

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

This test measures the level of C-reactive protein in your blood, a protein produced by your liver in response to inflammation.

Quick summary

["CRP helps track 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
87371-1
Short code
EC fedF gene Islt Ql NAA+probe
Synonyms
EC fedF gene Islt Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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 This Test Is Done

Doctors may order a CRP 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 assess risks for conditions like heart disease or certain cancers.

What to Expect Before the Test

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

What the Results Mean

Higher CRP levels often indicate inflammation, but results alone don’t diagnose a specific condition. Your doctor will compare your results with your medical history and other tests to understand what’s happening in your body.

Common Conditions Monitored

CRP is commonly used to monitor conditions like rheumatoid arthritis, lupus, or heart disease. It may also help track infections, such as pneumonia or urinary tract infections, or guide decisions about treatments like steroids.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Plasma)

Frequently asked questions

How long does it take to get CRP test results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing time. Your doctor will discuss the results with you during your follow-up visit.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and stress can influence inflammation. Eating a heart-healthy diet, staying active, and managing stress may help lower CRP levels over time.
Is CRP the same as a complete blood count (CBC)?
No, CRP measures inflammation specifically, while a CBC checks for red and white blood cell counts, platelets, and other blood components. Both tests serve different purposes in diagnosing health issues.
  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