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C-reactive protein (CRP) by turbidimetry in serum/plasma

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

This test measures the level of C-reactive protein, a protein produced by your 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
87320-8
Short code
ETEC heat-lab tox DNA Islt Ql NAA+probe
Synonyms
ETEC heat-lab tox DNA 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 Is This Test Done?

Your doctor may order this test to check for signs of inflammation, monitor chronic conditions like rheumatoid arthritis or lupus, or evaluate your risk for heart disease. It can also help determine how well your body is responding to treatment for an infection 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 doctor know before the test.

What the Results Mean

Higher than normal levels of CRP may indicate inflammation, infections, or other health issues. Lower levels might suggest your body is responding to treatment or that inflammation is under control. Your doctor will interpret the results in the context of your overall health.

Common Conditions Monitored

CRP is often used to track conditions like infections (e.g., pneumonia, urinary tract infections), autoimmune diseases (e.g., rheumatoid arthritis, lupus), heart disease, and post-surgical recovery. It can also help guide decisions about starting or adjusting medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CRP (Serum/Plasma)

Frequently asked questions

What causes elevated CRP levels?
Elevated CRP levels can be caused by infections (like bacterial infections), injuries, surgeries, or inflammatory diseases. Stress, certain medications, or smoking may also temporarily increase CRP. Your doctor will consider your symptoms and other test results to determine the cause.
Can CRP levels change over time?
Yes, CRP levels can fluctuate based on your health status, treatments, or underlying conditions. Regular monitoring may be needed if you have chronic inflammation or a condition requiring long-term management.
Is CRP the only test to measure inflammation?
No, CRP is one of many markers used to assess inflammation. Other tests, like erythrocyte sedimentation rate (ESR) or specific autoantibody tests, may also be used depending on your symptoms and diagnosis.
  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