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C-reactive protein, serum/plasma concentration (high-sensitivity)

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

This test measures the level of a protein called C-reactive protein (CRP) in your blood. CRP is a marker that helps your body detect inflammation, often in response to infections, injuries, or other conditions causing swelling.

Quick summary

["hs-CRP helps doctors assess low-grade inflammation that may not show up with other tests."]

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

Key facts at a glance

LOINC
37922-2
Short code
XR UE 2V
Synonyms
XR UE 2V
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
20
Ref high
400
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
CPT
82670
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

Healthcare providers may order hs-CRP to check for signs of inflammation that could be linked to conditions like heart disease, autoimmune disorders, or chronic infections. It’s sometimes used alongside other tests to monitor overall health or guide treatment decisions.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw if your test involves fasting. Wear comfortable clothing and plan to stay near the testing site for a short time.

How the Test Works

A small amount of blood is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to measure CRP levels using a sensitive immunoassay method.

What the Results Mean

Results are reported in milligrams per liter (mg/L). Higher levels may indicate inflammation, while lower levels suggest minimal or no inflammation. Your doctor will interpret results in relation to your health history and other tests.

Reference range

Premenopausal: 20-400 pg/mL; Postmenopausal: <30 pg/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

hs-CRP

Frequently asked questions

What does a high hs-CRP level mean?
A high hs-CRP level may signal chronic inflammation, which can be linked to conditions like atherosclerosis (plaque buildup in arteries), rheumatoid arthritis, or other inflammatory diseases. It’s not a definitive diagnosis but may prompt further evaluation.
What does a low hs-CRP level mean?
A low hs-CRP level suggests reduced inflammation, which could be normal or may indicate a lower risk of certain inflammatory or cardiovascular conditions. It doesn’t rule out all possible causes of inflammation.
Can lifestyle changes affect hs-CRP levels?
Yes, lifestyle factors like diet, exercise, smoking, and stress can influence CRP levels. Reducing inflammation may involve adopting heart-healthy habits, managing stress, or treating underlying conditions like obesity or poor sleep.
  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