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:
-
CRP (C-reactive protein) – a sensitive marker for acute inflammation
-
ESR (erythrocyte sedimentation rate) – reflects overall inflammatory activity
-
Leukocytes (white blood cells) – increase in infections and inflammation
-
Calprotectin – a stool marker important in diagnosing bowel inflammation
Other important markers:
-
Procalcitonin (PCT) – indicates bacterial infections and risk of sepsis
-
Interleukin-6 (IL-6) – a marker for systemic inflammation
-
AA/EPA ratio – balance of pro- and anti-inflammatory fatty acids
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?
The following values are considered within the normal range:
| Parameter | Reference Range |
|---|---|
| CRP | < 10 mg/L |
| hs-CRP | > 2 mg/L |
| ESR (women < 50 / > 50 y/o) | < 20 mm/h / < 30 mm/h |
| ESR (men < 50 / > 50 y/o) | < 15 mm/h / < 20 mm/h |
| Leukocytes | 4,000 – 11,000 / µL |
| Calprotectin (stool) | < 50 µg/g |
| Procalcitonin (PCT) | < 0.05 ng/mL |
| Interleukin-6 (IL-6) | < 7 pg/mL |
Note: These values may vary depending on age, gender, pregnancy, or pre-existing conditions. Always interpret values in a broader clinical context.
Source: Cleveland Clinic, n.d.; NHS, n.d.; Cleveland Clinic, 2021; Cleveland Clinic, 2022; Mayo Clinic, 2022
What causes elevated inflammatory markers?
Elevated inflammation markers can be triggered by a variety of conditions, not just acute illness. Common causes include:
-
Acute infections (bacterial or viral)
-
Chronic inflammatory conditions (e.g., rheumatoid arthritis, Crohn’s disease)
-
Autoimmune diseases
-
Cardiovascular diseases and arteriosclerosis
-
Cancer
-
Injuries, surgeries, or healing processes
-
Lifestyle factors: excess weight, physical inactivity, stress, smoking, alcohol, sleep deprivation
Causes of acutely elevated inflammatory markers
-
Insect bites, cuts, and bruises trigger localized acute inflammation.
-
Infections from bacteria, viruses, or parasites cause immediate immune responses.
-
Allergic reactions (e.g. to pollen, pet dander, food) provoke short-term inflammation.
Sources: Hannoodee & Nasuruddin, 2022.
Causes of chronically elevated inflammatory markers
-
Prolonged exposure to irritants (e.g. industrial chemicals)
-
Persistent allergies, e.g. to dust mites or pets
-
Autoimmune diseases like rheumatoid arthritis
-
Unresolved acute inflammation can become chronic
-
Chronic inflammation is often silent but may lead to long-term damage
Source: 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: Eat plenty of fruits, vegetables, whole grains, nuts, seeds, and omega-3-rich fish (e.g., salmon). Include antioxidants (from berries, green tea, broccoli) and vitamin C (from citrus fruits, bell peppers). Use anti-inflammatory spices like turmeric and ginger. Avoid processed foods, added sugars, and trans fats.
- Healthy weight: Excess abdominal fat produces pro-inflammatory substances. Losing weight helps lower low-grade chronic inflammation.
- Exercise: Physical activity reduces inflammation, especially in people with obesity or chronic illness.
- Stress & sleep: Chronic stress raises cortisol, which can worsen inflammation. Use relaxation methods like meditation or yoga. Prioritize 7–9 hours of quality sleep, as sleep deprivation is linked to higher inflammatory markers.
- Smoking & alcohol: Smoking causes oxidative stress and inflammation. Excessive alcohol harms the gut lining and immune function. Both should be reduced or avoided.
Source: Cleveland Clinic, 2024; John Hopkins, 2024; Beavers et al., 2010; Harvard Health, 2024; Rosemann et al., 2012
How are inflammatory markers tested?
Depending on the marker, measurement is done via:
-
Blood samples (CRP, ESR, IL-6, PCT, leukocytes)
-
Stool samples (Calprotectin, used in diagnosing bowel diseases)
Homed-IQ allows you to conveniently test selected inflammation markers such as CRP from home – including laboratory analysis and digital results. 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.
