hs-CRP Cardiovascular Risk Calculator
hs-CRP Cardiovascular Risk Calculator
Classify cardiovascular risk from high-sensitivity CRP using the AHA/CDC categories, and see when the result is not interpretable at all.
hs-CRP Cardiovascular Risk
CRP → risk categoryhs-CRP 2.4 mg/L
AHA/CDC categories
- hs-CRP
- the same molecule as standard CRP, measured with a more sensitive assay
- > 10 mg/L
- reflects infection, injury or inflammation rather than vascular risk — repeat once well
- two samples
- the recommended protocol is two samples at least 2 weeks apart, both taken when well, averaged
Worked example
hs-CRP 2.4 mg/L
2.4 mg/L is at or above 1 but below 3 mg/L → average relative risk
Confirm with a second sample at least 2 weeks apart, both taken when clinically well, and average the two
AHA/CDC hs-CRP categories
| hs-CRP | Category |
|---|---|
| < 1 mg/L | Low relative risk |
| 1 – 3 mg/L | Average relative risk |
| > 3 mg/L | High relative risk |
| > 10 mg/L | Acute-phase response — not interpretable for vascular risk, repeat |
What hs-CRP adds, and its limits
High-sensitivity CRP is not a different molecule from standard CRP — it is the same acute-phase reactant, produced by the liver under interleukin-6 stimulation, measured with an assay sensitive enough to resolve the low concentrations relevant to vascular risk rather than the higher concentrations relevant to acute infection.
The AHA/CDC categories divide the population into three roughly equal groups: under 1 mg/L is low relative cardiovascular risk, 1 to 3 mg/L is average, and above 3 mg/L is high. Above 10 mg/L the result no longer reflects vascular risk at all — it reflects an active acute-phase response, from infection, injury or another inflammatory process, and should be repeated once the patient is clinically well rather than acted on. Because a single measurement can be raised by a trivial and unnoticed stimulus, guidelines recommend two samples at least two weeks apart, both taken when the patient is well, with the result taken as their average.
Its role in practice is genuinely modest, and it is worth being candid about that. hs-CRP adds only a small amount of discrimination on top of an established risk score, and the JUPITER trial showed a statin benefit in people with a raised hs-CRP and an LDL that was already at target — an important result, but not one that has translated into a recommendation for routine population screening. It is best used selectively, in patients near a treatment threshold where the added information might change a decision.
Frequently asked questions
What is a high hs-CRP for cardiovascular risk?
Above 3 mg/L, the AHA/CDC high-risk category. Between 1 and 3 mg/L is average risk, and below 1 mg/L is low risk.
Why is hs-CRP above 10 mg/L not interpretable?
At that level the result reflects an active acute-phase response — infection, injury or another inflammatory process — rather than baseline vascular risk. It should be repeated once the patient is well rather than used for risk stratification.
Is hs-CRP the same test as standard CRP?
Yes, the same molecule. The difference is the assay: hs-CRP is measured with a more sensitive method capable of resolving the low concentrations relevant to cardiovascular risk.
Should hs-CRP be checked routinely to assess heart disease risk?
Not universally. It adds modestly to established risk scores and supported statin benefit in the JUPITER trial for people with a raised hs-CRP and normal LDL, but routine population screening is not universally recommended — it is more useful selectively, near a treatment decision.
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References
- Pearson TA et al. Markers of inflammation and cardiovascular disease: AHA/CDC scientific statement. Circulation. 2003;107(3):499–511.
- Ridker PM et al. Rosuvastatin to prevent vascular events in men and women with elevated C-reactive protein (JUPITER). N Engl J Med. 2008;359(21):2195–207.