C-reactive protein (CRP) by nephelometry (serum/plasma)

Why CRP Matters in Your Health

CRP is a marker that signals inflammation, which can occur due to infections, injuries, or certain health conditions. High levels may indicate an active inflammatory process, while lower levels suggest reduced inflammation. This test is often used alongside other assessments to guide treatment decisions or monitor chronic conditions like arthritis or heart disease.

When This Test Is Ordered

Your healthcare provider may order CRP testing to evaluate symptoms such as fever, joint pain, or swelling. It’s also used during follow-ups for conditions like rheumatoid arthritis, heart disease, or after surgery to check for signs of infection or inflammation. Sometimes, it’s included in routine check-ups for people at higher risk of inflammatory diseases.

What to Expect During the Test

A small blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed using a nephelometry method to measure CRP levels. The process takes about 15–30 minutes, and you may feel slight discomfort but no lasting effects. No special preparation is needed, though fasting may be advised in some cases depending on your provider’s instructions.

Interpreting Your Results

Results are typically reported in milligrams per liter (mg/L). While reference ranges vary by lab, very high levels (above 10 mg/L) often signal acute inflammation, while moderate levels (3–10 mg/L) may indicate chronic inflammation or risk factors like obesity or smoking. Your provider will discuss these results in the context of your overall health and symptoms.