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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 doctors assess 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
20475-0
Short code
CMV IgG SerPl-Imp
Synonyms
CMV IgG SerPl-Imp
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 Might Be Ordered

Your healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions like rheumatoid arthritis or heart disease, or evaluate your response to treatment. It can also help identify infections or determine if you’re healing properly after surgery or injury.

What to Expect Before the Test

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

What the Results Mean

Higher CRP levels often indicate inflammation, but they can also be elevated due to stress, certain medications, or other health issues. Your results will be compared to your healthcare provider’s expectations based on your medical history and symptoms.

Common Conditions Monitored

CRP is commonly used to track conditions like infections (e.g., pneumonia, urinary tract infections), autoimmune diseases (e.g., lupus, rheumatoid arthritis), heart disease, and post-surgical healing. It’s also sometimes used to screen for conditions like cancer.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CRP (Serum/Plasma)

Frequently asked questions

What does a high CRP level mean?
A high CRP level suggests inflammation is present in your body. While it doesn’t specify *where* or *why*, it can guide treatment decisions, such as adjusting medications or investigating further causes like infections or autoimmune activity.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a heart-healthy diet, staying active, and managing stress may help lower CRP levels over time, but results depend on individual health.
How often should CRP be checked?
Your provider will determine how often to check CRP based on your condition. Some people need it monthly, while others may only need it once or twice a year, depending on their treatment plan.
  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