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Biomarkers

hs-CRP — high-sensitivity C-reactive protein

High-sensitivity CRP — a marker of cardiovascular risk

hs-CRP — a vessel wall with low-grade inflammation and a test tube

hs-CRP (high-sensitivity C-reactive protein) is the same C-reactive protein, but measured with a more precise method capable of detecting small concentrations. "High-sensitivity" refers only to the assay technique, not to a different substance.

It is precisely the low CRP values that reflect low-grade "background" inflammation of the vessel wall, which is why hs-CRP is used as a marker of cardiovascular risk rather than for diagnosing acute infections.

Reference ranges

Cardiovascular risk categories by hs-CRP level (AHA/CDC interpretation):

Low riskunder 1 mg/L
Average risk1 – 3 mg/L
High riskover 3 mg/L
Acute inflammationover 10 mg/L
Important: When hs-CRP is above 10 mg/L, cardiac risk assessment is deferred: the value reflects an acute process, and the test is repeated after 2 weeks.

What an elevated level means

A persistently elevated hs-CRP (1–3 and especially over 3 mg/L) is associated with a higher risk of heart attack and stroke and reflects low-grade inflammation in atherosclerotic plaques. Very high values (over 10 mg/L) usually indicate an acute infection or flare rather than vascular risk.

What a low level means

A level below 1 mg/L is favorable: there is little background inflammation, and the contribution of the inflammatory component to cardiovascular risk is minimal. Quitting smoking, weight loss, physical activity and, when indicated, statins help lower hs-CRP.

How the test is done

Blood is drawn from a vein; fasting is not required. For risk assessment two measurements at least 2 weeks apart, outside acute illness, are needed; the average or the lower value is used. The test is performed with a high-sensitivity method (hs-assay).

What affects the value

  • Any infection, injury or surgery sharply raises CRP for days to weeks.
  • Obesity and smoking persistently raise the baseline level.
  • Hormone replacement therapy and estrogens raise CRP.
  • NSAIDs, statins and weight loss lower the value.
  • In women the baseline level is on average higher than in men.

Calculate using this marker

Calculators where hs-C-reactive protein is used directly:

Heart Age (QRISK) 10-year risk of heart attack and stroke (ACC/AHA Pooled Cohort equations) Open Metabolic Syndrome IDF/NCEP criteria — waist circumference, blood pressure, glucose, and lipids Open

Frequently asked questions

How does hs-CRP differ from ordinary CRP?

As a substance — not at all, it is the same protein. The difference is in the sensitivity of the method: the hs-test accurately measures low concentrations (0.3–1 mg/L) important for cardiac risk assessment, whereas ordinary CRP is designed for high "inflammatory" values.

Is an hs-CRP of 2 mg/L dangerous?

It indicates average cardiovascular risk. The value alone is not a diagnosis, but combined with other factors (LDL, blood pressure, smoking) it may tip the balance toward more active prevention. Retest outside of a cold and discuss it with your doctor.

Related terms

C-reactive protein A marker of inflammation in the body Inflammation markers Blood substances (hs-CRP, interleukins, ESR) that indicate chronic inflammation — a key mechanism of aging and most chronic diseases. ASCVD (Atherosclerotic cardiovascular disease) Atherosclerotic Cardiovascular Disease — the group of conditions caused by atherosclerosis: heart attack, stroke, coronary heart disease. Atherosclerosis The buildup of cholesterol plaques in artery walls — the main cause of heart attacks and strokes. Statins A class of drugs that lower LDL cholesterol by 30–55% — the cornerstone of heart-attack and stroke prevention. Myocardial infarction Death of a part of the heart muscle from complete blockage of a coronary artery — an acute, life-threatening condition. CVD Cardiovascular disease Metabolic syndrome A cluster of cardiometabolic risk factors PhenoAge Phenotypic biological age from 9 blood markers

Sources

  1. MedlinePlus — C-Reactive Protein (CRP) Test
  2. StatPearls — C-Reactive Protein
  3. StatPearls — Acute-Phase Reactants
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This content is educational and does not replace consultation with a physician. Reference ranges may vary depending on the laboratory and method — rely on the ranges stated on your own test report.
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