Skip to content

C-reactive protein (CRP) by nephelometry (high-sensitivity)

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

This test measures a protein in your blood that rises when your body is fighting inflammation, often used to check for signs of infection or inflammation.

Quick summary

["High CRP levels may signal inflammation needing further evaluation."]

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

Key facts at a glance

LOINC
6008-7
Short code
Prot C+ACA Ag PPP IA-aCnc
Synonyms
Prot C+ACA Ag PPP IA-aCnc
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 This Test Is Done

Your doctor may order this test to monitor conditions like arthritis, heart disease, or infections. It can also help track how well treatments are working or check for hidden inflammation in your body.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm to draw blood, similar to other blood tests. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

Results are typically reported in milligrams per liter (mg/L). Higher than normal levels may indicate inflammation, infection, or autoimmune conditions. Very low levels might suggest a lack of inflammation, but this isn’t always the case.

Common Conditions Monitored

This test helps diagnose or manage conditions like rheumatoid arthritis, heart disease (e.g., atherosclerosis), and infections. It’s also used in research or screening for early disease detection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP is a marker for systemic inflammation. While not diagnostic on its own, it can guide treatment decisions, especially in chronic conditions. Persistently elevated levels may prompt further testing for underlying causes.

Short name

hs-CRP

Frequently asked questions

What causes CRP levels to be high?
Infections (like colds or urinary tract infections), injuries, surgeries, or autoimmune diseases (such as lupus or rheumatoid arthritis) can raise CRP levels. Stress, certain medications, or even pregnancy may also affect results.
How often should I get this test?
Your doctor will determine the frequency based on your health needs. For example, people with heart disease might check CRP levels every few months, while others may only need it once.
Can diet or exercise affect CRP levels?
Yes! Reducing inflammation through diet (e.g., Mediterranean diet), exercise, and avoiding smoking can lower CRP levels. However, results depend on overall health and medical conditions.
  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