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C-reactive protein (CRP) by nephelometry

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

This test measures the level of C-reactive protein in your blood, a protein produced by your liver in response to inflammation or infection.

Quick summary

["CRP helps track inflammation, often used to monitor conditions like infections, autoimmune diseases, or after surgery."]

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

Key facts at a glance

LOINC
53339-8
Short code
11DC DBS-sCnc
Synonyms
11DC DBS-sCnc
Category
hormone
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Matters in Your Health

CRP is a marker for inflammation, which can signal infections, injuries, or chronic conditions like arthritis or heart disease. High levels may indicate an active inflammatory process, while low levels suggest reduced inflammation.

When This Test Is Ordered

Your doctor may order CRP testing to check for infections (e.g., pneumonia, urinary tract infections), evaluate autoimmune diseases (e.g., rheumatoid arthritis), assess heart health, or monitor healing after surgery or injury.

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 blood, and you can eat and drink as usual. Avoid strenuous activity before the test if instructed by your provider.

What the Results Mean

Results are typically reported in milligrams per liter (mg/L). Elevated CRP levels may prompt further testing or treatment adjustments, while normal levels usually indicate stable inflammation. Your doctor will interpret results in the context of your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is widely used in medicine because it provides a quick, objective measure of inflammation. It helps guide treatment decisions for conditions like sepsis, cardiovascular disease, and inflammatory bowel disease. While CRP is not specific to any single disease, it is a valuable tool for monitoring overall inflammatory activity in the body.

Short name

CRP (Nephelometry)

Frequently asked questions

How often will I need this test?
The frequency depends on your health condition. Some people may need CRP tested monthly, quarterly, or annually, while others may only need it once if their levels are stable. Your doctor will determine the best schedule for you.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. Eating a heart-healthy diet, staying active, and avoiding smoking may help lower CRP. Stress and poor sleep can also raise CRP, so managing these factors may support better test results.
What if my CRP is high but I don’t have symptoms?
A high CRP level without symptoms could indicate subclinical inflammation—low-level inflammation that isn’t causing obvious signs of illness. Your doctor may recommend lifestyle changes, further testing, or monitoring to understand the cause and address it effectively.
  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