What is a CRP test?
C-Reactive Protein (CRP) is an acute-phase protein produced by the liver within a few hours of infection, injury or inflammation. It rises rapidly (within 6–12 hours) and falls just as fast when the cause resolves — making it an excellent real-time marker of active inflammation. There are two types of CRP test: standard CRP (for detecting significant inflammation) and high-sensitivity CRP (hsCRP, for assessing heart disease risk at lower levels).
CRP Normal Range
| Test Type | Value | Interpretation |
|---|---|---|
| Standard CRP — Normal | < 6 mg/L | No significant inflammation |
| Standard CRP — Mild elevation | 6 – 50 mg/L | Mild inflammation / viral infection |
| Standard CRP — Significant | 50 – 200 mg/L | Active bacterial infection likely |
| Standard CRP — Severe | > 200 mg/L | Severe infection / serious condition |
| hsCRP — Low CV risk | < 1 mg/L | Low cardiovascular risk |
| hsCRP — Moderate CV risk | 1 – 3 mg/L | Moderate CV risk |
| hsCRP — High CV risk | > 3 mg/L | High cardiovascular risk |
What does HIGH CRP mean?
HIGH CRP above 6 mg/L
A high CRP means your body is fighting inflammation. Common causes: bacterial infections (pneumonia, UTI, appendicitis), viral infections (dengue, COVID-19), autoimmune conditions (rheumatoid arthritis, lupus, IBD), post-surgery or injury, heart attack (CRP rises within hours), cancer, and inflammatory bowel disease. The higher the CRP, the more severe the inflammation — though it doesn't tell you WHERE the inflammation is. Your doctor will combine CRP with symptoms and other tests to find the source.
CRP vs hsCRP — what's the difference?
Standard CRP vs High-Sensitivity CRP (hsCRP)
Standard CRP detects significant inflammation (infections, flares). It is not useful for detecting the very low-grade inflammation linked to heart disease. hsCRP (high-sensitivity CRP) measures tiny amounts of CRP and is used specifically to assess long-term cardiovascular risk — a persistently elevated hsCRP of 2–3 mg/L increases heart attack risk even in people with no obvious disease. If your doctor ordered hsCRP (not standard CRP), they are evaluating your heart risk, not looking for infection.
Questions to ask your doctor
- Is this standard CRP or hsCRP — and what specifically were you checking for?
- What is causing the elevated CRP?
- Do I need antibiotics or anti-inflammatory treatment?
- When should I recheck to confirm it has come down?