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C-reactive protein (CRP) concentration in plasma

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

This test measures the level of C-reactive protein, a substance 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
70161-5
Short code
C trach+GC pnl Ur NAA+probe
Synonyms
C trach+GC pnl Ur 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

Your doctor may order a CRP test to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate how your body is responding to an infection or treatment. It can also help determine if you have an infection before symptoms appear.

What to Expect Before the Test

No special preparation is needed for this test. You may have blood drawn from a vein in your arm, similar to other blood tests. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

Results are not provided as a single numeric range since CRP levels vary by condition and individual health. High levels often indicate inflammation, while low levels suggest minimal or no inflammation. Your doctor will interpret results in the context of your medical history and other tests.

Common Conditions Monitored

CRP is commonly used to track conditions like rheumatoid arthritis, lupus, heart disease, or infections such as pneumonia or sepsis. It can also help guide decisions about starting or stopping certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CRP levels often signal inflammation, which can be caused by infections, autoimmune diseases, or other health issues. While CRP itself doesn’t diagnose a specific condition, it provides important clues to guide further testing and treatment plans. Your doctor will use these results alongside other factors to make decisions about your care.

Short name

CRP (Plasma)

Frequently asked questions

What causes CRP levels to be high?
High CRP levels can be due to infections (like flu or urinary tract infections), inflammatory diseases (like arthritis), injuries, or certain medications. Stress, smoking, or obesity may also temporarily raise CRP levels.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition. Some people get it yearly, while others may need it more frequently if they have ongoing inflammation or chronic health issues.
Can lifestyle changes lower CRP levels?
Yes! Lifestyle changes such as eating a healthy diet, exercising regularly, quitting smoking, and managing stress can help lower CRP levels and reduce 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