Chronic inflammation has a terrible rep. Much of it is justified. Long-term inflammation, after all, contributes to chronic illnesses and deaths. If you only read headlines for health news, you could believe that eliminating inflammation will eliminate cardiovascular disease, cancer, dementia, and possibly aging itself. Unfortunately, that is not the case.
Nonetheless, our understanding of how chronic inflammation might harm health has grown significantly in recent years. With this perspective, three common questions arise: Could I be inflamed without realizing it? How will I know if I do? Is it possible to test for inflammation? Yes, there are.
In medical care, a number of well-established assays for detecting inflammation are widely employed. However, it is crucial to remember that these tests cannot discriminate between acute inflammation, which may occur as a result of a cold, pneumonia, or an injury, and chronic inflammation, which may occur as a result of diabetes, obesity, or an autoimmune illness, among other disorders. Understanding the distinction between acute and chronic inflammation is critical.
These are four of the most common inflammatory tests:
1. The rate of erythrocyte sedimentation (sed rate or ESR). This test determines how quickly red blood cells settle to the bottom of a vertical blood tube. When there is inflammation, red blood cells fall faster because more proteins in the circulation cause them to clump together. While ranges vary by lab, a normal result is often 20 mm/hr or less, with values over 100 mm/hr considered extremely high.
2. C-reactive protein (CRP) (CRP). When there is inflammation, this protein produced by the liver tends to rise. A typical concentration is less than 3 mg/L. CRP levels above 3 mg/L are commonly used to detect an elevated risk of cardiovascular disease, but bodywide inflammation can cause CRP levels to climb to 100 mg/L or higher.
3. Ferritin. This is a blood protein that indicates how much iron is stored in the body. It's usually requested to see if an anemic person is iron deficient, in which case ferritin levels are low. Ferritin levels may be elevated if there is an excess of iron in the body. However, ferritin levels rise when there is inflammation. Normal results differ by lab and are slightly higher in men, but a typical normal range is 20 to 200 mcg/L.
4. Fibrinogen. While this protein is most typically used to assess the health of the blood clotting system, its levels tend to rise when there is inflammation. Normal fibrinogen levels range from 200 to 400 mg/dL.
Are inflammatory tests useful?
In some cases, inflammatory tests can be extremely beneficial.
- Identifying an inflammatory condition One example is giant cell arteritis, an uncommon illness in which the ESR is almost invariably high. If a person has symptoms such as a new, severe headache and jaw pain, a raised ESR can increase the likelihood that the disease is present, but a normal ESR argues against this diagnosis.
- An inflammatory condition is being monitored. When a person has rheumatoid arthritis, ESR or CRP (or both tests) can assist establish how aggressive the illness is and how effectively treatment is working.
None of these tests are flawless. When inflammation is present, erroneous negative outcomes can occur. False positive results can occur when abnormal test results indicate inflammation when none exists.
Should you be tested for inflammation on a regular basis?
Inflammation tests are not yet part of standard medical care for all adults, and expert guidelines do not suggest them.
CRP testing to estimate cardiac risk is recommended to assist determine whether preventive medication is appropriate for some patients (such as those with an intermediate risk of a heart attack — that is, neither high nor low). However, data suggests that CRP testing adds nothing to established risk factors such as a history of hypertension, diabetes, smoking, high cholesterol, obesity, and a family history of heart disease.