Should I check for biomarkers such as high-sensitivity C-reactive protein (hs-CRP) to assess cardiovascular inflammation in this patient?

Should You Check hs-CRP or Other Biomarkers to Assess Cardiovascular Inflammation?

Check high-sensitivity C-reactive protein (hs-CRP) only if your patient is at intermediate cardiovascular risk (10-20% 10-year CHD risk), as it may help guide treatment decisions, but do not check it in low-risk or high-risk patients where it won't change management. 1, 2

When to Measure hs-CRP

Appropriate Candidates

• Intermediate-risk patients (10-20% 10-year CHD risk) are the primary target population where hs-CRP measurement is recommended (Class IIa evidence) 1, 2
• Use hs-CRP to help decide whether to intensify therapy (e.g., starting statins, aspirin) in these intermediate-risk patients where you're uncertain about treatment 1, 3
• The test adds independent prognostic information beyond traditional Framingham risk factors and may reclassify intermediate-risk patients to higher risk categories 2, 4

When NOT to Measure hs-CRP

• Do not screen low-risk patients - they don't need aggressive therapy regardless of hs-CRP 1
• Do not screen high-risk patients (>20% 10-year risk) - they already qualify for intensive treatment regardless of hs-CRP levels 2, 3
• Do not use hs-CRP to guide acute coronary syndrome management (Class III evidence) 1
• Do not use serial hs-CRP testing to monitor treatment effects (Class III evidence) 1

How to Measure hs-CRP Properly

Testing Protocol

• Obtain two separate measurements, averaged, optimally 2 weeks apart to account for within-individual variability 1, 2
• Patient should be metabolically stable without obvious infection or inflammatory conditions 1
• Can be measured fasting or nonfasting 1
• Results must be expressed in mg/L only 1

Interpreting Results

• Low risk: <1 mg/L 2, 3
• Moderate risk: 1-3 mg/L 2, 3
• High risk: >3 mg/L (approximately 2-fold increased relative risk compared to low-risk tertile) 2, 3

Critical Action Point

• If hs-CRP ≥10 mg/L: Discard this result and search for non-cardiovascular causes (infection, arthritis, other inflammatory conditions), then retest in 2 weeks 1, 3

Other Biomarkers: The Answer is No

Do not measure other inflammatory markers (cytokines, other acute-phase reactants) for cardiovascular risk determination (Class III evidence) 1

The evidence base supports only hs-CRP as the inflammatory marker with sufficient standardization, commercial availability, and predictive value for clinical use 1

Special Populations and Considerations

Factors That Elevate hs-CRP (Independent of CV Risk)

• Elevated blood pressure, obesity, cigarette smoking 2, 3
• Metabolic syndrome/diabetes 2
• Low HDL/high triglycerides 2, 3
• Estrogen/progestogen hormone use 1, 2
• Chronic infections and inflammation 2

Patients with Established Coronary Disease

• hs-CRP may be useful as an independent marker of prognosis for recurrent events, death, MI, and restenosis after PCI (Class IIa evidence) 1
• However, secondary prevention measures should NOT depend on hs-CRP determination (Class III evidence) 1

Common Pitfalls to Avoid

• Don't use hs-CRP as a substitute for traditional risk factor assessment - always calculate Framingham risk score first 1
• Don't measure hs-CRP during acute illness or active inflammation - results will be falsely elevated and non-predictive 1
• Don't use hs-CRP for population-wide screening - this is not recommended as a public health measure 1
• Don't rely on a single measurement - the two-measurement average provides more stable risk estimation 1, 2