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

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 or infection.

Quick summary

["CRP helps track inflammation in your body."]

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

Key facts at a glance

LOINC
50387-0
Short code
C trach rRNA Cvx Ql NAA+probe
Synonyms
C trach rRNA Cvx 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 healthcare provider may order this test to check for signs of inflammation, monitor conditions like rheumatoid arthritis, heart disease, or infections, or evaluate responses to treatments.

What to Expect Before the Test

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

What the Results Mean

Higher than expected levels may indicate inflammation, infection, or other health issues. Lower levels might suggest reduced inflammation. Your provider will interpret results in the context of your overall health.

Common Conditions Monitored

This test is often used to monitor conditions like autoimmune diseases, infections, heart disease, or to check how well treatments are working.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

What causes CRP levels to change?
CRP levels can rise due to infections, injuries, or inflammatory diseases. They may also be affected by medications, pregnancy, or other health conditions. Stress or recent illness can temporarily increase levels.
How often should I get this test?
Your provider will determine how often you need this test based on your health needs. Some people get it every few months, while others may need it less often.
Can I eat or drink before this test?
You can eat and drink normally unless your provider instructs otherwise. Avoiding alcohol or certain medications may be advised in some cases, so check with your provider.
  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