Skip to content

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 produced by your liver in response to inflammation.

Quick summary

["CRP helps your doctor assess inflammation in your body."]

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

Key facts at a glance

LOINC
39851-1
Short code
SPECT Kdny-Bl W Tc99mMAG3 IV
Synonyms
SPECT Kdny-Bl W Tc99mMAG3 IV
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nm-spect
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 doctor may order this test to check for signs of inflammation, monitor conditions like heart disease, rheumatoid arthritis, or infections, or evaluate how well treatments are working. High-sensitivity CRP is particularly useful for detecting early signs of inflammation that might not be obvious otherwise.

What Does a High or Low Result Mean?

Results can vary based on your health and medical history. A higher-than-normal CRP level may indicate inflammation, infections, or certain autoimmune diseases. A lower-than-normal level might suggest reduced inflammation, but it doesn’t rule out other conditions.

How Is This Test Performed?

A blood sample is drawn from a vein, usually in your arm. The blood is then sent to a lab where it is analyzed to measure CRP levels using a sensitive immunoassay method.

What Should You Expect Before or After the Test?

There are no special preparations needed for this test. You may feel slight discomfort from the needle, but it usually goes away quickly. After the blood is drawn, you can resume normal activities.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP is a marker for inflammation. It is often used alongside other tests to diagnose or monitor conditions like cardiovascular disease, infections, or inflammatory diseases. Elevated levels may signal an ongoing inflammatory process, while persistently low levels might suggest reduced inflammation but do not exclude other potential health issues.

Short name

hs-CRP

Frequently asked questions

What does a high CRP level mean?
A high CRP level may indicate inflammation in your body, which can be caused by infections, injuries, autoimmune diseases, or other health conditions. It’s important to discuss your results with your healthcare provider to understand the possible causes and next steps.
How often should I get this test?
Your doctor will determine the frequency of this test based on your medical needs. It might be done once or multiple times depending on your condition, treatment plan, or ongoing health monitoring.
Can lifestyle changes affect CRP levels?
Yes, lifestyle factors such as diet, exercise, smoking, and stress can influence inflammation levels. Making positive lifestyle changes, like eating a heart-healthy diet, staying active, and avoiding smoking, may help lower CRP levels and support overall health.
  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