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

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

This test measures the level of C-reactive protein in your blood, a marker often checked to assess inflammation or infection.

Quick summary

["CRP helps doctors track inflammation, infection risk, or response to treatment."]

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

Key facts at a glance

LOINC
76573-5
Short code
M catarr g1b Swab Ql NAA+probe
Synonyms
M catarr g1b Swab 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 CRP is Tested

Your healthcare provider may order this test to evaluate signs of inflammation, monitor conditions like arthritis, infections, or heart disease, or check how your body responds to treatments. It can also help determine if you’re at risk for certain complications, such as blood clots or heart attacks.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re concerned about needles or fasting, let your provider know so they can guide you through the process.

What the Results Mean

Higher CRP levels often indicate inflammation or infection, while lower levels suggest minimal inflammation. Your results will be compared to a general reference range provided by your lab, but individual results can vary based on health status, age, and other factors.

Common Conditions Monitored

CRP is commonly used to monitor conditions like rheumatoid arthritis, lupus, infections (such as pneumonia or sepsis), and heart disease. It can also help assess how well you’re responding to treatments for these conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CRP (Quantitative)

Frequently asked questions

How often do I need this test?
The frequency depends on your health condition and treatment plan. Some people get CRP tested monthly, quarterly, or annually, while others may need it only when symptoms appear or during follow-up visits. Your healthcare provider will determine the best schedule for you.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a heart-healthy diet, staying active, and managing stress may help lower CRP, but results can vary. Always follow your provider’s advice for managing your health.
What if my CRP is outside the normal range?
If your CRP is elevated, your provider may investigate further to identify the cause, such as an infection, autoimmune condition, or other health issue. If it’s low, they may still monitor it to ensure no underlying inflammation is present. Follow-up testing or additional questions may be needed to guide next steps.
  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