Understanding inflammatory markers
Inflammatory markers are laboratory parameters that indicate inflammation in the body. They include, among others, CRP (C-reactive protein), ESR (erythrocyte sedimentation rate), calprotectin, or the white blood cell count. These values increase when the body responds to infections, injuries, or chronic illnesses with an inflammatory reaction. They help to diagnose and monitor the severity and type of inflammation. Persistently elevated inflammatory markers are a known risk factor for cardiovascular diseases, such as coronary artery disease or atherosclerosis (Cleveland Clinic, 2022).
Table of Contents
- What are inflammatory markers?
- What are normal inflammatory marker levels?
- What causes elevated inflammatory markers?
- Are high inflammatory markers always bad?
- What are the effects of high inflammatory markers?
- What to do if inflammatory markers are elevated?
- How are inflammatory markers tested?
- Summary
What are inflammatory markers?
Inflammatory markers are blood indicators that show whether and to what extent an inflammatory reaction is occurring in the body. They play an important role in diagnosing and monitoring inflammatory processes. The most common markers of inflammation are:
- C-reactive protein (CRP): When there is inflammation in the body, the liver produces CRP. This protein enters the bloodstream, and an elevated level indicates inflammation.
- Erythrocyte sedimentation rate (ESR): This measures the rate at which red blood cells sink in a blood sample. A higher ESR is an indicator of the presence of inflammation.
- Calprotectin: This protein is released in the intestines when inflammation occurs there. The calprotectin level in stool serves as a biomarker for the diagnosis and monitoring of chronic inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. High levels indicate inflammation in the intestines.
The difference between CRP and ESR is that ESR varies depending on age and sex, e.g., in children, men, and women. Additionally, ESR decreases more slowly than CRP when inflammation subsides. To determine the cause of inflammation, possible accompanying symptoms should be considered (Menzel et al., 2021).
What exactly is meant by inflammation?
Inflammation is the body's defense response to damage caused by pathogens, injuries, or irritants. It serves to neutralize harmful influences and promote the healing process. The following types are distinguished:
| Acute inflammation | Chronic (long-term) inflammation |
|---|---|
| This is a rapid, intense reaction of the body aimed at eliminating immediate threats caused by injuries or infections. Acute inflammation is short-lived and is accompanied by typical symptoms such as redness, warmth, swelling, pain, and loss of function. | This form of inflammation develops more slowly and can persist over a long period, often without noticeable symptoms. Chronic inflammation is associated with a range of health problems, including heart disease and autoimmune disorders. |
Source: Harvard Health, 2020
What are normal inflammatory marker levels?
Normal inflammatory values for CRP (C-reactive protein) are generally below 10 mg/L, which indicates low inflammatory activity. For calprotectin in stool, normal values are below 50 µg/g, which typically suggests the absence of significant intestinal inflammation.
C-reactive protein (CRP) in blood:
Here are the usual reference values for C-reactive protein (CRP):
| CRP level (mg/L) | Interpretation |
|---|---|
| < 10 mg/L | Normal, no active inflammation |
| 50 mg/L | Moderate inflammation |
| 150 mg/L | Severe inflammation or infection |
| 200 mg/L | Very severe inflammation |
| > 300 mg/L | Possible sepsis or severe systemic inflammation |
Source: Cleveland Clinic, 2022
Additionally, there is high-sensitivity C-reactive protein (hs-CRP), a special type of CRP test that can detect even very low concentrations of CRP in the blood. Values from 2 mg/L are considered moderately elevated and may indicate an increased risk of cardiovascular disease (Mayo Clinic, 2022).
Calprotectin in stool:
| Calprotectin level (µg/g) | Interpretation |
|---|---|
| < 50 µg/g | Normal, no intestinal inflammation |
| 50–120 µg/g | Mild inflammation possible (e.g., treated inflammatory bowel diseases or related to use of non-steroidal anti-inflammatory drugs) |
| 120 µg/g | Indication of an active inflammatory process in the gastrointestinal tract |
| 200 µg/g | Strong indication of intestinal inflammation |
Erythrocyte sedimentation rate (ESR):
The normal ESR values vary depending on age and gender. For men under 50 years, a normal ESR is up to 15 mm/h, and for men over 50, up to 20 mm/h. For women under 50 years, the value should not exceed 20 mm/h, and for women over 50, not more than 30 mm/h. Elevated ESR levels may indicate inflammation or other medical conditions (Cleveland Clinic, 2022).
What causes elevated inflammatory markers?
Elevated inflammatory markers, such as increased CRP or calprotectin levels, are usually caused by infections, chronic inflammatory conditions (e.g., rheumatoid arthritis or inflammatory bowel diseases), injuries or tissue damage, autoimmune disorders, or severe illnesses such as sepsis. The body reacts to damage or infection with an inflammatory response, which leads to an increase in inflammatory markers in the blood or stool.
Causes of acutely elevated inflammatory markers
Common triggers of acute inflammation include insect bites and physical injuries such as cuts or bruises, which provoke localized inflammatory responses. Infections caused by bacteria, viruses, or other organisms also lead to acute inflammation, as the body reacts immediately to fight off the infection. Allergies also fall into this category, triggering acute inflammatory responses when the immune system overreacts to usually harmless substances like pollen, animal dander, or foods (Hannoodee & Nasuruddin, 2022).
Causes of chronically elevated inflammatory markers
Chronically elevated inflammatory markers may be caused by prolonged exposure to irritants such as industrial chemicals or ongoing allergic reactions—for example, to house dust mites or animal dander. Autoimmune diseases like rheumatoid arthritis also lead to persistent inflammation, as the immune system mistakenly attacks healthy tissue. In some cases, acute inflammation does not completely resolve and progresses into a chronic condition. These chronic inflammations are often symptomless and can go undetected, potentially leading to significant long-term health damage (Cleveland Clinic, 2024).
Other factors contributing to elevated inflammatory markers
General lifestyle factors can also promote inflammatory processes in the body. Being overweight may lead to a low-grade, chronic inflammatory response, which can be worsened by an inflammation-promoting diet high in fat and sugar. Smoking, chronic stress, and sleep problems also weaken the immune system and foster inflammation. For example, stress increases the release of cortisol, which stimulates the production of pro-inflammatory cytokines and other substances that can lead to low-grade inflammation (Christ et al., 2019; Liu et al., 2017).
Are elevated inflammatory markers always bad?
Elevated inflammatory markers can be normal during acute inflammation when the body is responding to injury or infection. However, chronically elevated levels are particularly problematic because they often go unnoticed and can increase the risk of developing diseases such as cardiovascular conditions or worsen existing diseases. Chronic inflammation can impair health over time.
What are the effects of elevated inflammatory markers?
While acute inflammation is generally part of the body’s normal defense mechanism, chronically elevated inflammatory markers negatively affect health and can promote various diseases and symptoms:
- Increased risk of cardiovascular diseases such as heart attacks and strokes
- Progression of chronic conditions like diabetes, cancer, arthritis, and autoimmune diseases
- Ongoing tissue damage and scarring (fibrosis)
- Impaired organ function such as liver, kidneys, or intestines
- Cognitive impairment and depression
- Nonspecific symptoms such as night sweats, fatigue, and loss of appetite
Due to these potential health risks, regular monitoring of inflammatory markers is important to detect possible problems early (Harvard Health, 2020; Fellman, 2023).
What to do if inflammatory markers are high?
If a blood test has revealed high inflammatory markers and you are experiencing symptoms or discomfort, it is advisable to consult a doctor. Depending on the cause, treatment may be necessary. However, you can also take steps on your own to help reduce elevated inflammatory markers:
- Anti-inflammatory diet
- Healthy weight
- Regular physical activity
- Stress management
- No smoking
- Low alcohol consumption
- Regular health check-ups
- Restful sleep
Source: Cleveland Clinic, 2024
Anti-inflammatory diet: An anti-inflammatory diet helps reduce inflammatory responses in the body. Anti-inflammatory foods include plenty of fruits and vegetables, whole grains, nuts, seeds, and fatty fish rich in omega-3 fatty acids. Antioxidants found in berries, green tea, broccoli, and spinach, and vitamin C from citrus fruits and bell peppers also play an important role in reducing inflammation. Ginger and turmeric are also believed to have anti-inflammatory properties. In contrast, inflammatory foods such as processed foods, refined sugar, saturated fats, and trans fats—often found in fast food and industrial baked goods—should be avoided (John Hopkins, 2024).
Healthy weight: Maintaining a healthy weight is important because overweight and obesity are associated with an increased risk of chronic inflammation. Fat tissue, particularly around the abdomen, produces inflammatory substances that can contribute to a persistent low-grade inflammatory state. Reducing fat tissue and reaching a healthy body weight can help lower these inflammatory responses.
Regular physical activity: Regular exercise can help reduce inflammation by supporting weight management. Studies have shown that physical activity has a positive effect on inflammatory markers, particularly in people with elevated levels due to chronic diseases or obesity (Beavers et al., 2010).
Stress management and sleep: Chronic stress increases the production of the hormone cortisol, which can promote inflammation when persistently elevated. Relaxation techniques such as meditation or yoga can help lower stress levels and reduce the risk of inflammatory processes. At the same time, sufficient and high-quality sleep is essential, as studies have linked sleep deprivation to elevated inflammatory markers (Harvard Health, 2024).
Reducing smoking and alcohol consumption: Smoking promotes oxidative stress, which increases inflammation and the risk of chronic disease. Excessive alcohol consumption can especially lead to inflammation in the gastrointestinal tract, damaging the mucous membrane and impairing normal function. Both habits should be reduced or avoided if you are struggling with high inflammatory markers (Rosemann et al., 2012).
How are inflammatory markers tested?
Inflammatory markers are measured using blood tests that detect indicators such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Homed-IQ offers a wide range of at-home tests that can detect various health issues associated with elevated inflammatory markers, including diabetes, heart health, and inflammatory bowel diseases. More information and ordering options can be found on the Homed-IQ website at the provided link.
Summary
Inflammatory markers provide insight into the presence and extent of inflammatory responses in the body. The most common markers are C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and fibrinogen. While acute inflammation is short-term and part of the normal immune response, chronically elevated inflammatory markers can indicate serious health issues. Regular testing of these markers is important to assess inflammation levels. Lifestyle habits such as a balanced diet and regular physical activity play a key role in reducing and managing inflammatory markers.
