A Test in Context: High-Sensitivity C-Reactive Protein

If one person can be said to own the science of inflammation in heart disease, it’s Paul Ridker — and this JACC “Test in Context” review is his definitive guide to using high-sensitivity CRP, the blood marker of that inflammation.

The practical scaffolding is clear: hsCRP under 1 mg/L is low risk, 1–3 moderate, over 3 higher (and over 10 likely a passing infection — repeat it). Its predictive weight rivals blood pressure or cholesterol. The pivotal evidence is the JUPITER trial, which showed a 47% cut in events from a statin given to people with low LDL but high hsCRP — and the “dual target” idea that the best outcomes come from getting both LDL under 70 and hsCRP under 2. Ridker is careful on a subtle point: CRP is a marker, not the cause; the real driver is upstream inflammation (IL-1, IL-6), which is what to target therapeutically.

The practical takeaway is to use hsCRP to sharpen the statin decision in uncertain cases, and to recognize inflammation as a treatable axis of risk alongside cholesterol. The resistance is guideline caution — hsCRP sits at Class IIb — and competition from coronary calcium for reclassifying risk.

We rate the evidence high: an authoritative synthesis from the field’s leading investigator, anchored in large cohorts and the JUPITER RCT, candid about its limits. Its clinical significance is high — it gives clinicians clear thresholds and a proven scenario (low LDL, high hsCRP) where treatment helps, and it lays the groundwork for the inflammation-targeting era.