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

Published: August 9, 2026Updated: August 15, 2026

This test measures a protein called C-reactive protein (CRP), which your body produces in response to inflammation. It’s often used to check for signs of inflammation in your body.

Quick summary

["hs-CRP helps track inflammation, which may relate to conditions like infections, autoimmune diseases, or heart risks."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
110108-8
Short code
CEA
Synonyms
CEA Msmt SerPl
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) - red-top or gold-top tube
Units
N/A
Ref low
0
Ref high
3
Critical range
— – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–99 years
Method
Immunoassay (Chemiluminescent Immunoassay - CLIA)
CPT
82378
SNOMED
82984-6
Specimen volume
1.0 mL serum (minimum 0.5 mL)
Stability
Room temperature: 8 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C): 3 months
Hemolysis max
100
Lipemia max
300
Icterus max
50
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Doctors may order hs-CRP to monitor chronic conditions like arthritis, heart disease, or after surgery to assess healing. It can also help evaluate whether you have an ongoing low-level inflammation that isn’t obvious from other tests.

What Does a High or Low Result Mean?

High CRP levels often signal inflammation, which can be linked to infections, injuries, or diseases like rheumatoid arthritis. Very high levels may indicate severe inflammation or infection. Low levels usually mean minimal inflammation, but they don’t rule out other conditions.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The lab uses a special technique called nephelometry to measure CRP levels precisely, often in very small amounts.

What Should You Expect Before the Test?

No special preparation is needed, but tell your doctor about any medications you’re taking, recent infections, or recent physical activity that might affect results.

Reference range

Non-smokers: <3.0 ng/mL; Smokers: <5.0 ng/mLN/A

Specimen: serum

No special patient preparation required. Specimen collection is not affected by fasting status.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

hs-CRP

Frequently asked questions

How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing schedule.
Can I eat or drink before this test?
You can eat and drink normally before this test, as it doesn’t require fasting.
Does this test require any special conditions, like fasting?
No fasting is required for this test, but if you’re on blood thinners or have a history of bleeding disorders, let your doctor know before the test.
  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 15, 2026. · Read our editorial policy