What Is CRP in a Blood Test?

CRP stands for C-Reactive Protein. Produced by your liver in response to inflammation anywhere in your body. Rises within hours of tissue injury.

Normal Range

• Below 3 mg/L — low cardiovascular risk
• 3–10 mg/L — moderate (chronic inflammation, obesity)
• Above 10 mg/L — acute inflammation or infection
• Above 100 mg/L — usually acute bacterial infection

Standard CRP vs hs-CRP

• Standard CRP: detects acute inflammation and infection
• hs-CRP: cardiovascular risk assessment
• hs-CRP below 1: low CV risk
• hs-CRP 1–3: average risk
• hs-CRP above 3: high CV risk

Elevated CRP Causes

• Bacterial infection — rises dramatically
• Viral infection — rises modestly
• Autoimmune disease — RA, lupus, IBD
• Obesity
• Smoking
• Trauma or surgery
• Cancer

Clinical Use

• Distinguish bacterial from viral infection
• Monitor autoimmune disease activity
• Assess cardiovascular risk (hs-CRP)
• Monitor anti-inflammatory treatment response