What is the CRP Test?
C-Reactive Protein (CRP) is a substance produced by the liver in response to inflammation in the body. The CRP test measures the level of this protein in your blood. When there is infection, injury, or inflammation anywhere in the body, CRP levels rise rapidly.
Why is This Test Done?
- To detect and monitor infections (bacterial, viral)
- To assess the level of inflammation in your body
- To monitor inflammatory conditions like rheumatoid arthritis or lupus
- To check response to treatment for infections or inflammatory diseases
- To help differentiate between bacterial and viral infections
- As a marker for dengue fever severity and other tropical infections common in Sri Lanka
How to Prepare for the CRP Test
Simple Preparation
- No fasting required. You can eat and drink normally.
- The test can be done at any time of the day.
- Inform your doctor if you are taking anti-inflammatory drugs (ibuprofen, aspirin, etc.) as they can affect results.
- Continue other medications as usual unless told otherwise.
Understanding Your Results
| CRP Level (mg/L) | What It Means | Possible Causes |
|---|---|---|
| Less than 5 mg/L | Normal - No significant inflammation | Healthy state |
| 5 - 10 mg/L | Mild inflammation | Mild viral infection, minor injury, early-stage inflammation |
| 10 - 50 mg/L | Moderate inflammation | Significant viral infection, moderate bacterial infection, active inflammatory disease |
| 50 - 100 mg/L | High inflammation | Serious bacterial infection, dengue with complications, acute flare of inflammatory disease |
| Above 100 mg/L | Severe inflammation | Severe bacterial infection, sepsis, major tissue injury. Requires urgent medical attention. |
CRP in Common Conditions in Sri Lanka
- Dengue fever: CRP rises and is used to monitor disease progression. Very high CRP may indicate complications.
- Urinary tract infections: Moderate to high CRP depending on severity.
- Pneumonia: Usually significantly elevated CRP.
- Common cold/flu: CRP may be mildly elevated or normal.
- Post-surgery: CRP normally rises after surgery and should come down as healing progresses.
What Should You Do Next?
- Normal CRP: No action needed regarding inflammation.
- Elevated CRP: Your doctor will look at it together with your symptoms, physical examination, and other tests to determine the cause.
- Very high CRP (above 50): Indicates a serious condition. Follow your doctor's advice closely and do not delay treatment.
- Monitoring: If you're being treated for an infection, CRP should drop as you recover. A repeat test may be ordered.
Important: CRP is a general marker of inflammation. It does not tell you exactly what is wrong or where. Your doctor uses it alongside other investigations to make a diagnosis. Never self-diagnose based on CRP alone.