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Let’s face it: inflammation has a bad reputation. Much of it is well-deserved. After all, long-term inflammation contributes to chronic illnesses and deaths. If you just relied on headlines for health information, you might think that stamping out inflammation would eliminate cardiovascular disease, cancer, dementia, and perhaps aging itself.

Unfortunately, that’s not true.

Still, our understanding of how chronic inflammation can impair health has expanded dramatically in recent years. And with this understanding come three common questions: Could I have inflammation without knowing it? How can I find out if I do? Are there tests for inflammation? Indeed, there are.

Testing for inflammation

A number of well-established tests to detect inflammation are commonly used in medical care. But it’s important to note these tests can't distinguish between acute inflammation, which might develop with a cold, pneumonia, or an injury, and the more damaging chronic inflammation that may accompany diabetes, obesity, or an autoimmune disease, among other conditions. Understanding the difference between acute and chronic inflammation is important.

These are four of the most common tests for inflammation:

• Erythrocyte sedimentation rate (sed rate or ESR). This test measures how fast red blood cells settle to the bottom of a vertical tube of blood. When inflammation is present the red blood cells fall faster, as higher amounts of proteins in the blood make those cells clump together. While ranges vary by lab, a normal result is typically 20 mm/hr or less, while a value over 100 mm/hr is quite high.
• C-reactive protein (CRP). This protein made in the liver tends to rise when inflammation is present. A normal value is less than 3 mg/L. A value over 3 mg/L is often used to identify an increased risk of cardiovascular disease, but bodywide inflammation can make CRP rise to 100 mg/L or more.
• Ferritin. This is a blood protein that reflects the amount of iron stored in the body. It’s most often ordered to evaluate whether an anemic person is iron-deficient, in which case ferritin levels are low. Or, if there is too much iron in the body, ferritin levels may be high. But ferritin levels also rise when inflammation is present. Normal results vary by lab and tend to be a bit higher in men, but a typical normal range is 20 to 200 mcg/L.
• Fibrinogen. While this protein is most commonly measured to evaluate the status of the blood clotting system, its levels tend to rise when inflammation is present. A normal fibrinogen level is 200 to 400 mg/dL.

Are tests for inflammation useful?

In certain situations, tests to measure inflammation can be quite helpful.

• Diagnosing an inflammatory condition. One example of this is a rare condition called giant cell arteritis, in which the ESR is nearly always elevated. If symptoms such as new, severe headache and jaw pain suggest that a person may have this disease, an elevated ESR can increase the suspicion that the disease is present, while a normal ESR argues against this diagnosis.
• Monitoring an inflammatory condition. When someone has rheumatoid arthritis, for example, ESR or CRP (or both tests) help determine how active the disease is and how well treatment is working.

None of these tests is perfect. Sometimes false negative results occur when inflammation actually is present. False positive results may occur when abnormal test results suggest inflammation even when none is present.

Should you be routinely tested for inflammation?

Currently, tests of inflammation are not a part of routine medical care for all adults, and expert guidelines do not recommend them.

CRP testing to assess cardiac risk is encouraged to help decide whether preventive treatment is appropriate for some people (such as those with a risk of a heart attack that is intermediate — that is, neither high nor low). However, for most people evidence suggests that routine CRP testing adds relatively little to assessment using standard risk factors, such as a history of hypertension, diabetes, smoking, high cholesterol, and positive family history of heart disease.

So far, only one group I know of recommends routine testing for inflammation for all without a specific reason: companies selling inflammation tests directly to consumers.

Inflammation may be silent — so why not test?

It’s true that chronic inflammation may not cause specific symptoms. But looking for evidence of inflammation through a blood test without any sense of why it might be there is much less helpful than having routine health care that screens for common causes of silent inflammation, including

• excess weight
• diabetes
• cardiovascular disease (including heart attacks and stroke)
• hepatitis C and other chronic infections
• autoimmune disease.

Standard medical evaluation for most of these conditions does not require testing for inflammation. And your medical team can recommend the right treatments if you do have one of these conditions.

The bottom line

Testing for inflammation has its place in medical evaluation, and in monitoring certain health conditions such as rheumatoid arthritis. But it’s not clearly helpful as a routine test for everyone. A better approach is to adopt healthy habits and get routine medical care that can identify and treat the conditions that contribute to harmful inflammation.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

Quick health quiz: how bad is inflammation for your body?

You’re forgiven if you think inflammation is very bad. News sources everywhere will tell you it contributes to the top causes of death worldwide. Heart disease, stroke, dementia, and cancer all have been linked to chronic inflammation. And that’s just the short list. So, what can you do to reduce inflammation in your body?

Good question! Before we get to the answers, though, let’s review what inflammation is — and isn’t.

Inflammation 101

Misconceptions abound about inflammation. One standard definition describes inflammation as the body’s response to an injury, allergy, or infection, causing redness, warmth, pain, swelling, and limitation of function. That’s right if we’re talking about a splinter in your finger, bacterial pneumonia, or the rash of poison ivy. But it’s only part of the story, because there’s more than one type of inflammation:

• Acute inflammation rears up suddenly, lasts days to weeks, and then settles down once the cause, such as an injury or infection, is under control. Generally, acute inflammation is a reaction that attempts to restore the health of the affected area. That’s the type described in the definition above.
• Chronic inflammation is quite different. It can develop for no medically apparent reason, last a lifetime, and cause harm rather than healing. This type of inflammation is often linked with chronic disease, such as:
• • excess weight
  • diabetes
  • cardiovascular disease, including heart attacks and stroke
  • certain infections, such as hepatitis C
  • autoimmune disease
  • cancer
  • stress, whether psychological or physical.

Which cells are involved in inflammation?

The cells involved with both types of inflammation are part of the body’s immune system. That makes sense, because the immune system defends the body from attacks of all kinds.

Depending on the duration, location, and cause of trouble, a variety of immune cells, such as neutrophils, lymphocytes, and macrophages, rush in to create inflammation. Each type of cell has its own particular role to play, including attacking foreign invaders, creating antibodies, and removing dead cells.

4 inflammation myths and misconceptions

Inflammation is the root cause of most modern illness.

Not so fast. Yes, a number of chronic diseases are accompanied by inflammation. In many cases, controlling that inflammation is an important part of treatment. And it’s true that unchecked inflammation contributes to long-term health problems.

But inflammation is not the direct cause of most chronic diseases. For example, blood vessel inflammation occurs with atherosclerosis. Yet we don’t know whether chronic inflammation caused this, or whether the key contributors were standard risk factors (such as high cholesterol, diabetes, and smoking — all of which cause inflammation).

You know when you’re inflamed.

True for some conditions. People with rheumatoid arthritis, for example, know when their joints are inflamed because they experience more pain, swelling, and stiffness. But the type of inflammation seen in obesity, diabetes, or cardiovascular disease, for example, causes no specific symptoms. Sure, fatigue, brain fog, headaches, and other symptoms are sometimes attributed to inflammation. But plenty of people have those symptoms without inflammation.

Controlling chronic inflammation would eliminate most chronic disease.

Not so. Effective treatments typically target the cause of inflammation, rather than just suppressing inflammation itself. For example, a person with rheumatoid arthritis may take steroids or other anti-inflammatory medicines to reduce their symptoms. But to avoid permanent joint damage, they also take a medicine like methotrexate to treat the underlying condition that’s causing inflammation.

Anti-inflammatory diets or certain foods (blueberries! kale! garlic!) prevent disease by suppressing inflammation.

While it’s true that some foods and diets are healthier than others, it’s not clear their benefits are due to reducing inflammation. Switching from a typical Western diet to an “anti-inflammatory diet” (such as the Mediterranean diet) improves health in multiple ways. Reducing inflammation is just one of many possible mechanisms.

The bottom line

Inflammation isn’t a lone villain cutting short millions of lives each year. The truth is, even if you could completely eliminate inflammation — sorry, not possible — you wouldn’t want to. Among other problems, quashing inflammation would leave you unable to mount an effective response to infections, allergens, toxins or injuries.

Inflammation is complicated. Acute inflammation is your body’s natural, usually helpful response to injury, infection, or other dangers. But it sometimes sparks problems of its own or spins out of control. We need to better understand what causes inflammation and what prompts it to become chronic. Then we can treat an underlying cause, instead of assigning the blame for every illness to inflammation or hoping that eating individual foods will reduce it.

There’s no quick or simple fix for unhealthy inflammation. To reduce it, we need to detect, prevent, and treat its underlying causes. Yet there is good news. Most often, inflammation exists in your body for good reason and does what it’s supposed to do. And when it is causing trouble, you can take steps to improve the situation.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD