Wednesday, August 15, 2018
Wisdom Wednesday: C- Reactive Protein (CRP) Test
A C-reactive protein test measures the level of C-reactive protein (CRP) in your blood. CRP is a protein made by your liver. It’s sent into your blood stream in response to inflammation. Inflammation is your body’s way of protecting your tissues if you’ve been injured or have an infection. It can cause pain, redness, and swelling in the injured or affected area. Some autoimmune disorders and chronic diseases can also cause inflammation. Normally, you have low levels of c-reactive protein in your blood. High levels may be [a] sign of a serious infection or other disorder.
If you’ve already been diagnosed with an infection or have a chronic disease, this test may be used to monitor your treatment. CRP levels rise and fall depending on how much inflammation you have. If your CRP levels go down, it’s a sign that your treatment for inflammation is working.
The CRP test is sometimes confused with a high-sensitivity-(hs) CRP test. Although they both measure CRP, they are used to diagnose different conditions. An hs-CRP test measures much lower levels of CRP. It is used to check for risk of heart disease.
This is the kind of “dummied-down” information currently being released by NIH (National Institutes of Health) rather than reporting on cutting edge research.
Although the information presented is fairly accurate, it is also misleading. The hs-CRP also measures inflammation but it is specific for vascular inflammation. As such, it can be an indicator of cardiac risk. When elevated, the hs-CRP stimulates LDL cholesterol to bind with homocysteine and create plaque in an inflamed artery wall. At low levels this is a form of repair, protecting the damaged artery from rupture. However, when excessive, artery occlusion or clots can occur resulting in a CVA, stroke or pulmonary embolism.
Excessive plaque is labeled as “vulnerable plaque”. The body responses to vulnerable plaque by laying down calcium to make the plaque adhere to the artery wall. This is the basis of the high-speed CT scan “calcium score”. The higher the calcium score, the greater the presence of vulnerable plaque. Despite the protective nature of the calcium, there is a wide-spread believe, even among physicians, that the calcium is the cause of the plaque. I frequently must counsel patients that have been misinformed about the role of calcium in heart disease.
The most common cause of a “false-high” hs-CRP is dental disease. Active infection in the gums will inflame the vascular bed raising the hs-CRP to high levels. At one time, it was suggested that dentists should routinely run the hs-CRP but that has not become a standard of practice.
I run the hs-CRP as a part of my routine laboratory testing. I believe it is a much better indicator of cardiac risk than the total cholesterol and LDL. However, I also run the serum lipids, homocysteine and fibrinogen routinely to evaluate cardiac risk.
If I suspect autoimmune disease or infection, then the standard CRP is performed as a part of an immune profile. The SED rate, ANA, and other antibody tests round out the profile.
Both the CRP and hsCRP are valuable laboratory tests in evaluating inflammation depending on the cause. However, other tests must be performed to properly evaluate these test results.
Source: August 6, 2018 Medline Plus