Measuring Inflammation: The Differences Between ESR and CRP

Inflammation gets a bad rap, but it’s a necessary process for the body to protect itself. In inflammation, the body uses its own immune system to heal injuries. Short-term (acute)  inflammation is a healthy and necessary bodily process. But when inflammation malfunctions and goes on longer than necessary — that’s chronic inflammation, which can be harmful to health.

Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are two markers that can be measured from a blood sample. They represent the level of inflammation in the body at the time of the test. 

If you’ve had lab work done and had high levels of ESR or CRP, you may be worried about what this means for you. Here’s the short answer: It really depends on how high the levels are, and what else is going on with your overall health.

What are ESR and CRP?

ESR is the measure of how quickly red blood cells (erythrocytes) drop (or create sediment) in a test tube. It’s measured in millimeters per hour. It’s an indirect marker of the inflammation levels in the body, because when inflammation is high, it takes longer for the red blood cells to drop. CRP is a protein that the liver creates in response to inflammation, so its levels in the blood increase when the body is inflamed.

What is the relation between ESR and CRP?

The most important thing to understand about the relation between ESR and CRP is that they both increase with active inflammation. There are some differences in the timing of when they increase. CRP is quicker — it rises faster and falls more quickly (about 3 days) after inflammation is resolved. ESR takes longer to rise and also stays higher for longer after inflammation is resolved.

What are the normal ranges for CRP and ESR?

This can vary based on the laboratory that is running the blood tests. An individual’s “normal” level of CRP and ESR can depend on their age, sex, and active chronic diseases. 

• A normal CRP level is <1.0 mg/dL (or <10 mg/L, depending on the units that the lab is using). 

• A normal ESR is usually <20 mm/hour. 

The normal ESR range can also be broken down further by age and sex.

What diseases cause high ESR/CRP?

There are many diseases and conditions that cause inflammation, which can raise ESR/CRP. A high ESR/CRP doesn’t point to one specific disease or group of diseases. They are helpful, but pretty non-specific tests. 

Here are some of the most common diseases associated with high ESR/CRP levels:

• Autoimmune diseases: In diseases like rheumatoid arthritis and lupus, the immune system attacks its own body. This chronic inflammation means that ESR/CRP levels go up — and stay up. Monitoring ESR/CRP levels in autoimmune disease can help you and your healthcare team know how well your treatment is working.

• Infection: When your body is infected by a bacteria or virus, it ramps up its inflammatory response to fight the invader. This causes a raised ESR/CRP, which then goes back down once the infection resolves.

• Cancer: In cancer, the fast, uncontrolled growth and turnover of cells causes  inflammation levels to rise, leading to high ESR/CRP. 

• Lack of blood flow: Cells become injured when they don’t get the nutrients they need to function. In a heart attack or stroke, cells don’t get the blood or oxygen they need, and this can cause increased inflammation — and raised ESR/CRP levels.

• Bodily injury: After a physical injury, like a bad fall or car accident, your body needs to repair what is broken. The body does this by increasing inflammation throughout the body to fix the injured area.

What are the symptoms of high ESR/CRP?

A high ESR or CRP alone does not cause any symptoms. But the conditions that lead to the high ESR/CRP will usually cause symptoms. 

In autoimmune diseases, those symptoms may be pain, fatigue, rashes, or joint swelling. In infection, the symptoms may include a fever, too. It’s hard to give a list of specific symptoms. That’s because there are many, varied conditions that cause high ESR and CRP levels. 

How can I reduce my ESR and CRP?

A CRP/ESP that is raised due to an acute process (like a minor infection or injury) will reduce on its own once the infection or injury resolves — you don’t need to do anything for the number to improve. A chronically elevated ESR/CRP is different, and treatment may be necessary to reduce the ESR/CRP back into the normal range. Here are some ways that medications can be used to combat high inflammation:

• Target the inflammation directly: Some medications, like steroids and NSAIDs, work to reduce inflammation that is acutely causing discomfort. They work in the short term, but they usually don’t solve the underlying cause of the inflammation.

• Treat the underlying disease: Other medications can decrease ESR/CRP by treating the underlying cause of the inflammation. For example, DMARDs can treat autoimmune diseases, and antibiotics can treat serious infections. 

There’s a lot that’s still not fully understood about chronic inflammation. It’s likely to play a role in much more than we can grasp at the present — from early childhood trauma and gut health to cardiovascular disease — and more. 

New research is being done to explore the ways that lifestyle changes, in addition to medical treatment, may be used to reverse chronic inflammation. For example, it’s possible that diet changes could help. This review explored the ways that eating fresh, unprocessed foods may reduce chronic inflammation. Another new study found a link between social isolation and elevations in inflammatory markers. This suggests that staying connected with people around you could potentially lower your risk of chronic inflammation.