Acute-phase reactant serum concentration (e.g., C-reactive protein, fibrinogen, or similar inflammatory marker)

What Is This Test Measuring?

Your blood contains many proteins that change in response to your body’s needs. Some, like **acute-phase reactants**, increase when you have an infection, injury, or inflammation. This test measures the concentration of one or more of these proteins, often including markers like C-reactive protein (CRP) or fibrinogen. These proteins don’t have a single, universally accepted name, so your results may refer to a group of related substances.

Why Might You Need This Test?

Healthcare providers use this test to monitor conditions such as infections (e.g., bacterial or viral), autoimmune diseases (e.g., rheumatoid arthritis), heart disease, or post-surgery healing. It may also be used to check for signs of inflammation after trauma or during certain treatments.

When Might You Get This Test?

You might receive this test if you have symptoms like fever, swelling, pain, or fatigue; if you’re recovering from surgery or an illness; or if your doctor suspects an underlying inflammatory condition. Some tests are done as part of routine check-ups or follow-up care.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for a few hours before the blood draw, but this depends on your healthcare provider’s instructions. On the day of the test, avoid smoking or consuming alcohol for at least 24 hours if directed.