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

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 or infection in your body.

Quick summary

["CRP helps identify inflammation, infections, or other health conditions affecting your body."]

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

Key facts at a glance

LOINC
45085-8
Short code
C trach rRNA Nph Ql Probe
Synonyms
C trach rRNA Nph Ql 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
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 chronic conditions like arthritis or heart disease, or evaluate symptoms such as fever, joint pain, or swelling. It can also help assess infection risk or response to treatment.

What to Expect Before the Test

No special preparation is needed. You may have blood drawn from a vein in your arm, similar to other blood tests. If you’re on blood thinners, inform your provider beforehand.

What the Results Mean

Higher than expected CRP levels may indicate inflammation, infections, or autoimmune conditions. Lower levels might suggest reduced inflammation, but results depend on clinical context and other factors.

Common Conditions Monitored

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

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 rise?
CRP levels can rise due to infections (like bacterial or viral), injuries, surgeries, or inflammatory diseases. Stress, smoking, or certain medications may also affect results.
Can diet or lifestyle affect CRP levels?
Yes, diet high in processed foods, sugar, or unhealthy fats may increase inflammation and CRP levels. Regular exercise, a balanced diet, and managing stress can help lower CRP over time.
How often should CRP be checked?
Frequency depends on your condition. Some people get CRP checked annually or as needed for monitoring chronic diseases, while others may have it tested during acute symptoms or before procedures.
  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