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C-reactive protein (CRP) in 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 or autoimmune diseases."]

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

Key facts at a glance

LOINC
87951-0
Short code
EC eaeA gene Stl Ql NAA+probe
Synonyms
EC eaeA gene Stl Ql NAA+probe
Category
chemistry
Sample
stool
Container
Clean container
Units
N/A
Ref low
0
Ref high
5
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
CPT
82378
SNOMED
394995008
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions (such as rheumatoid arthritis or heart disease), or evaluate responses to treatments. It can also help diagnose infections or identify risks for certain health issues.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein (usually in your arm) to draw a blood sample. If you’re anxious, let your provider know so they can offer comfort measures.

What the Results Mean

Higher-than-normal CRP levels may indicate inflammation, infections, or other health problems. Lower levels suggest minimal inflammation. Your provider will interpret results in the context of your overall health and symptoms.

Common Conditions Monitored

CRP is often used to track conditions like heart disease, autoimmune disorders (e.g., lupus), or infections. It’s also part of screening for certain cancers or monitoring treatment progress.

Reference range

Non-smokers: <2.5 ng/mL; Smokers: <5.0 ng/mLN/A

Specimen: stool

No special preparation required. For PSA, avoid sexual activity for 24-48 hours before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is a sensitive marker for inflammation, meaning it can detect mild to moderate levels that other tests might miss. While not specific to a single condition, it helps guide decisions about further testing, treatment adjustments, or lifestyle changes. Always discuss results with your provider to understand their full meaning for your health.

Short name

CRP (Plasma)

Frequently asked questions

What causes CRP levels to change?
CRP rises in response to infections (like a cold or flu), injuries, or inflammatory diseases. It can also be affected by stress, certain medications, or smoking. Chronic conditions (e.g., arthritis) may lead to consistently elevated levels over time.
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 yearly for routine checks, while others may need it more frequently if they have ongoing conditions.
Can diet or lifestyle affect CRP levels?
Yes! Eating a heart-healthy diet, staying active, managing stress, and avoiding smoking can help lower CRP levels. Small lifestyle changes may not immediately change test results, but they can support long-term health.
  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