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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 certain treatments."]

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

Key facts at a glance

LOINC
45068-4
Short code
C trach+GC DNA Cvx Ql NAA+probe
Synonyms
C trach+GC DNA 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 doctor may order this test to check for signs of inflammation, evaluate conditions like infections, autoimmune disorders, or to monitor responses to treatments such as chemotherapy or immune-modulating therapies. It can also help track inflammation after injuries or surgeries.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood sample 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

Higher CRP levels often indicate inflammation, but results alone don’t diagnose a specific condition. Your doctor will interpret the results in the context of your symptoms, medical history, and other tests.

Common Conditions Monitored

Elevated CRP levels may be seen in infections (like pneumonia or urinary tract infections), autoimmune diseases (like rheumatoid arthritis), heart disease, or after surgeries or injuries. Low levels may suggest no active inflammation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Nephelometry)

Frequently asked questions

What causes CRP levels to change?
CRP levels can rise due to infections, injuries, surgeries, or certain medications. They may also be higher in people with autoimmune diseases or heart disease. Stress, smoking, or certain foods can temporarily affect CRP levels, but they usually return to normal once the cause is gone.
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 regularly to monitor chronic inflammation, while others may need it only during flare-ups or after specific treatments.
Can diet or lifestyle affect CRP levels?
Yes, diet and lifestyle can influence CRP levels. Eating a heart-healthy diet, exercising regularly, and managing stress may help lower CRP. Avoiding smoking and limiting alcohol can also support healthier inflammation levels.
  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