C-reactive protein (CRP) – Serum

Why Is CRP Tested?

Doctors may order a CRP test to check for signs of inflammation, which can occur due to infections (like pneumonia or urinary tract infections), injuries, or certain medical conditions such as rheumatoid arthritis or heart disease. It can also help monitor how well treatments are working for these conditions.

What Does CRP Tell You?

Higher CRP levels often indicate inflammation. While CRP alone doesn’t diagnose a specific condition, it can guide further testing or treatment decisions. Very high levels might suggest severe infections or other serious health issues that need prompt attention.

How Is the Test Done?

A blood sample is taken from a vein, usually in your arm. The blood is sent to a lab where it is processed to measure CRP levels. The test typically takes a few hours to complete, and results are usually available within 24 hours.

What Are Common Results and What Do They Mean?

Results are usually reported in milligrams per liter (mg/L). A normal range can vary by lab, but generally, lower levels (often below 1 mg/L) suggest minimal inflammation. Moderate levels (1–3 mg/L) may indicate mild to moderate inflammation, while higher levels (above 3 mg/L) could signal more serious inflammation or infection.