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C-reactive protein (CRP) measured by immunoassay (probe-based)

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

This test measures a protein called C-reactive protein (CRP) in your blood, which helps your doctor assess inflammation in your body.

Quick summary

["CRP helps track 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
36903-3
Short code
C trach+GC DNA Spec NAA+probe
Synonyms
C trach+GC DNA Spec 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 CRP is Tested

Your doctor may order this test to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate responses to treatments. It can also help identify infections or other inflammatory processes in your body.

How the Test Works

A small blood sample is taken, and the CRP protein is detected using a specialized immunoassay probe. This method identifies CRP levels with high sensitivity, often used for quick and reliable results.

What to Expect Before the Test

No special preparation is needed for this test. You may have a slight pinch when the blood is drawn, but it usually takes only a few minutes. Avoid strenuous activity or heavy meals before the test if instructed by your provider.

Common Uses and Conditions

CRP is commonly used to monitor conditions such as rheumatoid arthritis, lupus, or other autoimmune diseases. It may also be checked during infections, after surgeries, or to assess heart disease risk.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CRP Probe Test

Frequently asked questions

What does an elevated CRP mean?
An elevated CRP level often indicates inflammation in your body, which can be caused by infections, injuries, or autoimmune diseases. However, it can also be normal if you have a mild or acute condition. Your doctor will interpret results in the context of your overall health and symptoms.
What does a normal CRP level suggest?
A normal CRP level usually means there is little to no inflammation detected in your blood. However, it doesn’t rule out other conditions that might not cause inflammation. Your doctor will use the results along with other tests and symptoms to make a diagnosis.
How often should CRP be checked?
CRP testing frequency depends on your health needs. Some people may need it monthly, quarterly, or annually, especially if they have chronic conditions like heart disease or arthritis. Your doctor will determine the best schedule for you.
  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