Inflammation and immunity
hs-CRP
An extra-sensitive CRP measurement of mild, smoldering inflammation, used as an additional measure of cardiovascular risk.
Everything about this testWhat it measures
hs-CRP (high-sensitivity CRP) measures the same protein as the regular CRP test, C-reactive protein, but with a method that also measures very low concentrations accurately. Such low values go with mild, long-lasting inflammation, among other places in the walls of the blood vessels. That is why hs-CRP is used as a measure of the risk of cardiovascular disease, not to detect an acute infection. With a clearly raised value, there is probably an acute inflammation and the value says nothing about cardiovascular risk.
- Mild, long-lasting (low-grade) inflammation that is linked to a higher risk of cardiovascular disease
- Unintentionally also acute infections or inflammations, with a clearly raised value
High
A slightly raised hs-CRP fits a higher risk of cardiovascular disease, provided there is no other inflammation. The value is then an indication of smoldering inflammation in the body, which is linked to overweight, smoking, little exercise, lack of sleep, diabetes and getting older. It is a risk measure, not a disease: someone with a high value has no symptoms from the value itself. With a clearly raised value, there is usually an acute infection or inflammation, a recent injury or heavy exercise; the measurement should then be repeated after a few weeks.
Low
A low hs-CRP fits a low level of inflammation and, together with other factors, a lower risk of cardiovascular disease. A low value is no guarantee: the most important risk factors, such as high blood pressure, high cholesterol, smoking and diabetes, are separate from hs-CRP and weigh more heavily.
If your result is abnormal
With a raised value without an explanation, the GP usually repeats the measurement after a few weeks and assesses the usual risk factors; with a clearly raised value, the first step is to look for an acute inflammation. According to the guideline, a raised hs-CRP on its own does not lead to medication.
Reliability
hs-CRP is a risk marker, not a diagnostic test. In large population studies, a higher value is linked to a higher risk of cardiovascular disease, but the added value on top of age, sex, smoking, blood pressure, cholesterol and diabetes is limited. The risk is estimated with the risk table (SCORE2) based on these standard factors; hs-CRP is not part of it and usually does not change that estimate. There are no agreed cutoff values for including hs-CRP in that estimate.
Limitations
- Any infection, injury, surgery, gum inflammation or heavy exercise in the weeks before the sample collection raises the value; the measurement should then be repeated, preferably two measurements at least two weeks apart.
- Overweight, smoking, the contraceptive pill and hormone therapy raise hs-CRP; statins and anti-inflammatory drugs lower it.
- The value does not point to the location of the inflammation and says nothing about the cause.
- Cutoff values for cardiovascular risk come from American research; there are no agreements about them in the Netherlands.
How common is this
In 2024, more than 1.7 million people in the Netherlands had a cardiovascular disease, more men than women, and in that year more than 38,000 people died from it. A slightly raised hs-CRP occurs in a considerable share of healthy adults, especially with overweight and smoking; there are no Dutch figures on this.
Who is this useful for
Cardiovascular risk is mainly determined by age, sex, smoking, blood pressure and cholesterol; hs-CRP adds little to that. The test can give additional information for people who want to follow their level of inflammation, for example with overweight, a sedentary life or intensive sport, but it usually does not change the risk estimate. Not useful during an ongoing infection, shortly after surgery or during an active inflammatory disease; the value cannot be interpreted then.
Downsides and risks
- A raised hs-CRP can cause worry about the heart and blood vessels, while the value usually does not change the risk estimate or the treatment plan.
- A coincidentally raised value due to an unnoticed infection can wrongly be read as a raised cardiovascular risk.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results