Also known as: High-sensitivity CRP, hs-CRP
Name: High-sensitivity C-reactive protein
Related tests: Cardiovascular risk, Total cholesterol, HDL cholesterol, Lipid profile, Triglycerides
Why is the test done?
To detect inflammation and monitor its response to treatment.
When is the test done?
When an acute or chronic inflammatory disease is suspected, such as autoimmune disorders like some types of arthritis or inflammatory bowel disease, or when an infection is suspected. [Note: high-sensitivity C-reactive protein (hs-CRP) is measured to assess cardiovascular risk].
What samples are required?
A blood sample from a vein.
What is being analysed?
C-reactive protein is a protein produced by the liver and released into the bloodstream. Because plasma CRP concentrations rise within a few hours of the onset of an infection, CRP is particularly useful for monitoring its course. The rise in plasma levels often precedes pain, fever or other clinical signs. CRP levels can increase tens of times in response to inflammation; they fall relatively quickly as the inflammation subsides, which makes the test a useful tool for assessing the effectiveness of treatment.
How is the sample collected for testing?
The sample is taken from a vein in the arm.
How is it used?
When is it requested?
What does the test result mean?
Is there anything else I should know?
How is it used?
CRP testing is ordered whenever an active infection is suspected. It may also be requested for patients with inflammatory bowel disease and some forms of arthritis and autoimmune disease (chronic inflammatory diseases in general) to determine the extent of the ongoing inflammatory process and to monitor treatment. CRP is also measured in patients who have had surgery or other invasive procedures to check for infection during the recovery period. CRP is not specific enough to diagnose a particular disease; rather, it is a general marker of infection and inflammation, and a rise should prompt further tests so that the most appropriate treatment can be started.
When is it requested?
As plasma CRP concentrations rise with inflammation, this test is requested when there is a risk of acute inflammation (as with a post-operative infection) or when inflammation is suggested by the patient’s clinical signs. CRP testing is also requested to assess some autoimmune diseases, such as rheumatoid arthritis and lupus. The test can also be used to monitor the effectiveness of anti-inflammatory therapy, as CRP levels vary in proportion to the degree of ongoing inflammation.
CRP is also used as an early marker of infection during wound healing and to monitor patients who have had surgical procedures, organ transplants or burns.
What does the test result mean?
A high plasma CRP level suggests an acute infection or inflammatory state. In a healthy person, the CRP concentration is generally below 10 mg/L. In some infections and inflammatory states, plasma CRP can reach 100 mg/L.
Plasma CRP levels follow the course of the inflammation; CRP values above 10 mg/L can therefore indicate clinically active inflammation.
Is there anything else I should know?
Another useful test for monitoring the course of inflammation is the erythrocyte sedimentation rate (ESR). Both tests are markers of an ongoing inflammatory process and should always be considered together for a correct diagnosis and for monitoring treatment.
1. What are chronic inflammatory diseases?
2. What is the difference between CRP and high-sensitivity CRP?
1. What are chronic inflammatory diseases?
Chronic inflammatory diseases are conditions characterised by long-term or recurrent inflammation. This can be found in various conditions, such as rheumatoid arthritis, lupus and inflammatory bowel disease (e.g. Crohn’s disease).
2. What is the difference between CRP and high-sensitivity CRP?
Both tests measure the same molecule in the blood, but the sensitivity of the methods used is different. High-sensitivity CRP is generally used to assess cardiovascular risk in apparently healthy people and measures the protein in a concentration range of 0.5 to 15 mg/L. Standard CRP, on the other hand, is ordered for patients at risk of bacterial or viral infections (such as after surgery) or for patients with chronic inflammatory diseases (such as rheumatoid arthritis) and measures the protein in a concentration range of 10 to 100 mg/L.