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C-reactive protein (CRP) in serum/plasma (high-sensitivity)

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

This test measures a protein called C-reactive protein, which your body produces in response to inflammation. It helps doctors assess low-level inflammation that may not be obvious from other tests.

Quick summary

["hs-CRP helps track subtle inflammation linked to heart disease and other conditions."]

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

Key facts at a glance

LOINC
48052-5
Short code
WBC nRBC cor # Fld
Synonyms
WBC nRBC cor # Fld
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.5
Ref high
11
Critical range
2 N/A – 30 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85004
SNOMED
900000000000003002
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 Is This Test Done?

Your healthcare provider may order this test to monitor chronic conditions like heart disease, rheumatoid arthritis, or other inflammatory disorders. It’s also used to check for signs of infection or inflammation after surgery or injury.

What Does a High or Low Result Mean?

Elevated levels may signal inflammation, infection, or conditions like autoimmune diseases. Lower-than-normal levels might suggest reduced inflammation, but they don’t always indicate a healthy state.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is separated into serum or plasma for testing. This test often requires fasting, but your provider will confirm instructions.

Common Conditions Monitored

High-sensitivity CRP is commonly used to evaluate cardiovascular risk, track inflammatory diseases, or assess healing after trauma or surgery.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Inflammation and Risk Assessment

Short name

hs-CRP

Frequently asked questions

What causes false high or low results?
Results can be affected by recent illness, medications (like steroids), or certain foods. If you’re unsure about your test results, discuss them with your provider.
How often should I get this test?
Your provider will determine the frequency based on your health needs. Regular monitoring may be needed for chronic conditions like heart disease or arthritis.
Can I eat or drink before this test?
Typically, fasting is required, but always follow your provider’s specific instructions for the best accuracy.
  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