Why Did My Doctor Order a C-Reactive Protein Test?

The levels of many components suspended in your blood can tell your doctor a lot about your health status, and C-reactive protein (CRP) is no exception. Based on the findings of a physical exam, Jeffrey H. Graf, MD, often uses blood tests to gather more information about your health and prognosis. 

Dr. Graf provides detailed evaluations to monitor and maintain your health at his private practice on the Upper East Side of Manhattan in New York City. Labs such as a C-reactive protein test can offer insight into what’s going on inside your body, as well as whether ongoing treatments are working. 

If your doctor orders a C-reactive protein test, you may be curious about its purpose and how its results apply to your medical care. Here’s what you should know.

The role of C-reactive protein

Your liver produces C-reactive protein, which infiltrates your bloodstream when inflammation is present in your body. The less inflammation you have, the less of this protein is in your blood. 

Your body’s natural inflammatory response occurs after injuries, with infections, or when other harmful stimuli damage your tissues. This response involves the release of inflammatory cells and cytokines, whose job it is to trap bacteria and initiate the healing process. 

At the same time, your liver releases C-reactive protein. Its role is to bind to damaged tissue and provide early defense against pathogens (viruses and bacteria) and other damaging factors. 

When C-reactive protein tests are necessary

C-reactive protein tests can’t diagnose the cause of inflammation or locate its source, but they can tell your doctor how much inflammation is present in your body. This inflammation can either be acute (short-term) or chronic (long-term). 

Your physician might order a C-reactive protein test if you have symptoms indicating inflammation-causing conditions including infections and autoimmune diseases. If the results of your CRP test indicate inflammation, your doctor orders additional diagnostic tests to pinpoint the cause. 

Inflammation detected on a CRP test can come from a wide range of acute and chronic conditions, including:

• Cardiovascular disease
• Bacterial infections 
• Inflammatory bowel disease
• Rheumatoid arthritis
• Lupus
• Vasculitis
• Pelvic inflammatory disease
• Asthma and other lung diseases
• Fungal infections

Some of these diseases are chronic and involve flare-ups when symptoms and complications worsen. A CRP test can detect a flare-up if you have lupus, rheumatoid arthritis, vasculitis, or another inflammatory disease. 

Sometimes CRP tests aren’t used to diagnose conditions but to monitor them instead. For example, your doctor might order a CRP test after surgery in case of an infection. CRP tests can also help your doctor determine the effectiveness of a particular treatment or medication for an inflammatory condition. 

The test requires no special preparation, and results are typically available in a day or two. 

Interpreting your results

Most adults with little or no inflammation have CRP levels less than 0.3 mg/dL. In some rare cases, CRP levels read low in people with inflammatory conditions like lupus or rheumatoid arthritis. Still, CRP tests are quite accurate in showing inflammation. 

Depending on the purpose of your test, Dr. Graf can interpret your results and what they mean for the future of your treatment. He can tell you if you need other diagnostic tests or if he needs to adjust your treatment plan. 

Acute or chronic inflammation can cause pain, fever, chills, or tachycardia (a rapid heartbeat). To find out if you need a CRP test for diagnostic or health-tracking purposes, contact Jeffrey H. Graf, MD, today.