C-Reactive Protein (CRP)

The C-Reactive Protein (CRP) test measures the level of CRP in the blood. CRP is a protein produced by the liver in response to inflammation. It is a nonspecific marker used to detect inflammation, infection, and monitor disease activity in conditions such as autoimmune disorders, cardiovascular disease, and infections.

1. What Is C-Reactive Protein?

• CRP is part of the body's immune response and is produced by the liver when there is inflammation in the body.

• It rises rapidly in response to infection, trauma, or tissue injury and returns to normal when the inflammation subsides.

• It is a sensitive but nonspecific marker—elevated CRP does not pinpoint the exact cause of inflammation.

2. Why Is the CRP Test Performed?

This test is used to:

• Detect acute inflammation due to infection, trauma, or surgery.

• Monitor chronic inflammatory conditions such as rheumatoid arthritis or lupus.

• Assess risk for cardiovascular disease (high-sensitivity CRP or hs-CRP).

• Evaluate the effectiveness of treatment for inflammation-related conditions.

3. CRP Reference Ranges

• Standard CRP:

  - Normal: < 10 mg/L

  - Mild elevation: 10 – 40 mg/L (may suggest mild inflammation or viral infection)

  - Moderate to high: > 40 mg/L (may suggest bacterial infection or significant inflammation)

• High-sensitivity CRP (hs-CRP) for cardiovascular risk:

  - Low risk: < 1.0 mg/L

  - Average risk: 1.0 – 3.0 mg/L

  - High risk: > 3.0 mg/L

4. How to Interpret CRP Results

🔹 Elevated CRP:

• May indicate infection, inflammatory disease, injury, or chronic illness.

• Persistently elevated CRP may be associated with an increased risk of cardiovascular events.

🔹 Normal or Low CRP:

• Indicates little or no current inflammation.

• May suggest effective treatment or resolution of an acute condition.

5. What Can Affect CRP Levels?

• Acute infections or injuries

• Chronic diseases (e.g., rheumatoid arthritis, lupus, inflammatory bowel disease)

• Obesity, smoking, and poor diet

• Heart disease or recent heart attack

• Use of anti-inflammatory medications or statins

6. How Is the Test Performed?

• A blood sample is drawn from a vein.

• No special preparation is typically required unless otherwise instructed.

7. When to See a Doctor

🚨 Contact your healthcare provider if you:

• Have persistent or unexplained elevated CRP levels.

• Are experiencing symptoms of infection, chronic inflammation, or heart disease.

• Are being monitored for an inflammatory or autoimmune condition.

🔹 Key Takeaways

✅ CRP is a nonspecific marker of inflammation and infection.

✅ It is useful for diagnosing and monitoring inflammatory conditions and cardiovascular risk.

✅ Elevated CRP should be interpreted with other clinical findings for accurate diagnosis.