Inflammation Testing
Evidence syntheses are pulled from our NiaHealth Research Foundations. These articles are intended for anyone who wants to better understand our approach to evidence, the tests we include in our platform, why we chose them, and how we interpret results.
Summary
Chronic inflammation is increasingly being recognized as a common pathogenic pathway for the development and progression of multiple chronic diseases that contribute to excess morbidity and mortality. As such, in addition to routinely testing and reporting several inflammatory biomarkers (hsCRP, white blood cell count, ferritin), NiaHealth offers an 'inflammatory panel' that includes multiple biomarkers that, when interpreted in combination, provide an assessment of chronic systemic inflammation. This evidence synthesis provides an overview of inflammation and briefly describes the inflammatory biomarkers included in the NiaHealth panel.
Background
Overview of inflammation
Inflammation plays an important role in restoration of homeostasis following exposure of the body to pathogenic or damaging stimuli, including infection, trauma, surgery, and chronic diseases (Cifuentes et al., 2025; Muscaritoli et al., 2025). In this setting, inflammation facilitates localization, containment, and elimination of these stimuli. However, persistence of the harmful stimulus or incomplete resolution of the inflammatory process can result in a chronic systemic inflammatory state, also known as systemic chronic inflammation (SCI). Chronic low-grade inflammation is strongly associated with the development of several increasingly prevalent chronic health conditions, including obesity, metabolic syndrome, cardiovascular disease, cancer, and central nervous system disorders (Cifuentes et al., 2025; Muscaritoli et al., 2025). Inflammation can be conceptualized as a continuum, where persistent low-grade inflammation leads to the development of chronic disease and higher inflammation can serve as a trigger for the development of autoimmune disease (Cifuentes et al., 2025). Immune dysregulation is also associated with accelerated aging and an increased risk of mortality (Cifuentes et al., 2025).
Physiology and pathophysiology of inflammation
Inflammation involves coordinated vascular, cellular, and molecular changes. The process begins with recognition of damage or pathogens through pattern recognition receptors such as Toll-like receptors and NOD-like receptors, which activate inflammatory signalling pathways involving cytokines, chemokines, and growth factors (Tate & Rao, 2024). Initially there is rapid recruitment of neutrophils and monocytes to the site of injury, accompanied by increased vascular permeability and the release of pro-inflammatory mediators including prostaglandins, leukotrienes, and cytokines such as IL-1β, IL-6, and TNF-α (Lucius, 2023). The release of cytokines from leukocytes is known as the cytokine cascade and induces tissue production of secondary mediators, which include IL-6 itself, chemokines, colony-stimulating factors, endothelial adhesion molecules, prostaglandins, and nitric oxide. These mediators contribute to the recruitment of leukocytes and enhance local innate immunity, facilitating the activation of the adaptive (antigen-specific) immune system (Mantovani & Garlanda, 2023). In addition to their local effects, many cytokines (including IL-6) enter the systemic circulation where they have widespread effects, including the production of acute-phase reactants in the liver (Lucius, 2023). Acute-phase reactants are hepatically synthesized proteins whose plasma concentrations change significantly during systemic activity, serving as sensitive markers of inflammatory activity. Acute-phase reactants that may be used clinically include C-reactive protein (CRP), fibrinogen, ferritin, serum amyloid A (SAA), transferrin, α1-antitrypsin, haptoglobin, albumin, and pentraxin 3 (Mantovani & Garlanda, 2023).
The acute-phase response is followed by a critical resolution phase where anti-inflammatory mediators – including IL-10, TGF-β, and specialized pro-resolving lipid mediators (SPMs) – actively terminate the inflammatory response (Rahtes et al., 2018). Resolution involves cessation of neutrophil infiltration, clearance of apoptotic cells and macrophage phenotype switching towards reparative functions (Rahtes et al., 2018). Resolvins are a specific type of SPM essential for removal of cellular debris. Resolvins are derived from omega-3 fatty acids (EPA and DHA), underscoring the importance of these fatty acids as anti-inflammatory agents (Menzel et al., 2021).
Chronic inflammation develops when resolution mechanisms fail or when the inciting stimulus persists (Rahtes et al., 2018). This can occur through several mechanisms, including: impaired production or function of pro-resolving mediators, defective clearance of apoptotic cells leading to secondary necrosis and continued inflammation, persistent activation of inflammatory signalling pathways, or ongoing exposure to inflammatory triggers. Chronic inflammation is characterized by sustained low-grade activation, with persistent infiltration of mononuclear cells (macrophages, lymphocytes, plasma cells) and simultaneous tissue destruction and attempted repair (Furman et al., 2019; Rajendran et al., 2018).
The transition to chronic inflammation is further promoted by accumulation of damage-associated molecular patterns (DAMPs) from cellular debris, mitochondrial dysfunction, misfolded proteins, and endoplasmic reticulum stress, all of which become prominent with advancing age (Liberale et al., 2022). Development of chronic inflammation is also perpetuated by environmental and lifestyle factors including poor diet (e.g. proinflammatory dietary profiles), physical inactivity, psychological stress, and environmental toxins (Furman et al., 2019).
Causes of chronic inflammation
Common triggers of systemic chronic inflammation include the following: chronic infections (such as CMV, EBV, hepatitis C), physical inactivity, obesity, microbiome dysbiosis, poor diet, isolation and chronic stress (including post-traumatic stress disorder [PTSD]), disturbed sleep, smoking, xenobiotics (Furman et al., 2019; Lucius, 2023).
There is also likely to be a bidirectional influence of cellular aging on the propensity of developing chronic inflammation and vice versa. Growing evidence suggests that cellular senescence contributes to the development of a systemic chronic inflammatory state in older individuals. Cellular senescence is characterized by an arrest of cell proliferation and development of a senescence-associated secretory phenotype (SASP), which includes increased secretion of pro-inflammatory cytokines, chemokines, and other pro-inflammatory cellular molecules (Coppé et al., 2010). Chronic inflammation, when present, increases oxidative stress and drives cellular aging (Furman et al., 2019).
Health effects of chronic inflammation
Chronic inflammation has been shown to have a plethora of negative effects on health behaviours and health outcomes, and in total, more than 50% of all deaths are attributable to inflammation-related diseases (GBD 2017 Causes of Death Collaborators, 2018).
Depending on the degree and extent of the inflammatory response, metabolic and neuroendocrine changes may also occur, for the purpose of conserving metabolic energy and allocating more nutrients to the activated immune system. This process may result in a constellation of energy-saving behaviours (also known as sickness behaviours) including anhedonia, sadness, fatigue, reduced libido, anorexia, altered sleep, and social withdrawal as well as increases in blood pressure, insulin resistance, and dyslipidemia, all of which have the potential to propagate chronic inflammation (Straub, 2017; Straub et al., 2010).
Mechanistic and clinical evidence demonstrates that systemic chronic inflammation leads to the development of cardiovascular disease, cancer, diabetes, chronic kidney disease, metabolic-associated steatotic liver disease (MASLD), autoimmune and neurodegenerative disorders (Furman et al., 2019). The effects of chronic inflammation are probably best established in the cardiovascular system, where it accelerates atherosclerosis, destabilizes plaques, and contributes to myocardial injury (Cifuentes et al., 2025). Accordingly, universal screening of hsCRP to evaluate for underlying inflammation has been recommended by the American College of Cardiology (Mensah et al., 2025). Chronic inflammation can also impair immune function, leading to increased susceptibility to infections and tumors, and poor response to vaccines (Furman et al., 2019).
Inflammatory biomarker candidates
Based on results of an initial literature review to determine the most clinically useful markers of chronic inflammation, and taking into account biomarkers that are already included in tests offered by NiaHealth, 20 tests were evaluated with respect to their ability to provide useful, accurate, and actionable information about inflammatory status. After a review of the literature, consideration of actionability, and evaluating the feasibility of accessing these tests in Canada, the following tests have been chosen for integration into the NiaHealth inflammation panel: hsCRP, fibrinogen, ferritin, NLR, WBC, and AA:EPA when available. A brief description of each of these tests is provided below:
High sensitivity C-reactive protein (hsCRP)
C-reactive protein (CRP) is an acute-phase reactant produced by hepatocytes in response to inflammatory stimuli – primarily interleukin-6 (IL-6), but also IL-1, and tumor necrosis factor (Plebani, 2023). Plasma levels of CRP can rise 100- to 1000-fold within 6-72 hours of an inflammatory stimulus (Mantovani & Garlanda, 2023), with a plasma half-life of approximately 19 hours.
In clinical practice, CRP serves as a sensitive but non-specific marker of systemic inflammation, tissue damage, and infection. Conventional CRP assays have a lower detection limit of 3-10 g/L, which is adequate to detect acute inflammation, infection, and tissue injury, where levels typically range from 10-200 mg/L, but may miss low-level chronic inflammation. Newer high-sensitivity CRP (hsCRP) assays are able to accurately measure concentrations down to 0.3 mg/L, enabling detection of chronic subclinical inflammation, which promotes the development of multiple non-communicable diseases, including ASCVD (Myers et al., 2004; Ridker, 2016).
Ferritin
As the body's primary iron storage protein, ferritin sequesters excess intracellular iron and stores it for future use, buffering against iron excess or deficiency in the blood (Kotla et al., 2022). The majority of ferritin is produced by the liver, with some contribution from the spleen and the bone marrow.
In clinical practice, serum ferritin is most often used as a biomarker of body iron stores, but it is also a positive acute-phase reactant, meaning that ferritin concentrations rise in the setting of inflammation, infection, malignancy, and liver disease (Kotla et al., 2022). Consequently, ferritin is useful for diagnosing iron deficiency when low, but elevations are non-specific and may reflect iron overload or a broad range of inflammatory conditions. When interpreted alongside other markers of inflammation, ferritin can provide an indication of an individual's underlying inflammatory status.
White blood cell (WBC) count
White blood cell (WBC) count measures the total number of white blood cells (leukocytes) in a given volume of blood (reported as ×10⁹/L on a CBC). WBC reflects immune system activity and is interpreted with the differential (neutrophils, lymphocytes, etc.), since the type of white cell driving a high or low result often matters more than the total alone (El Brihi & Pathak, 2025; Tefferi et al., 2005).
WBC can be used to help evaluate possible infection, inflammation, physiologic stress responses, medication effects (for example corticosteroids), bone marrow disorders, and immune suppression.
Neutrophil-to-lymphocyte ratio (NLR)
The neutrophil-to-lymphocyte ratio (NLR) is calculated as the neutrophil count divided by the lymphocyte count.
Neutrophils are the primary component of the innate immune response and typically increase significantly in inflammatory states, while lymphocytes are reflective of adaptive immune system activation. As such, the NLR provides a reflection of the balance between innate and adaptive immune responses (Muscaritoli et al., 2025). During an inflammatory response, neutrophils rise to a greater extent than lymphocytes, leading to an increase in NLR.
Fibrinogen
Fibrinogen (factor I) is a liver-produced plasma glycoprotein that is essential for coagulation and also an acute-phase reactant. Circulating fibrinogen levels reflect a mix of chronic inflammatory signalling (IL-6-driven hepatic production), pro-thrombotic physiology (blood viscosity, platelet aggregation), and confounding by lifestyle and metabolic factors (including smoking, adiposity). Inflammation from any source can increase fibrinogen levels. Much inter-individual variation in fibrinogen levels is explained by demographics including age and sex (~30%), established cardiovascular risk factors (~7%), and other inflammatory markers such as CRP (~10%) (Fibrinogen Studies Collaboration et al., 2007).
Arachidonic acid to eicosapentaenoic acid ratio (AA:EPA ratio)
The arachidonic acid (AA) to eicosapentaenoic acid (EPA) ratio is derived from the results from blood fatty acid testing and reflects the relative abundance of:
- Arachidonic acid (AA; 20:4n-6): a long-chain omega-6 polyunsaturated fatty acid (PUFA) that is a substrate for many bioactive lipid mediators (e.g. eicosanoids and other oxylipins)
- Eicosapentaenoic acid (EPA; 20:5n-3): a long-chain omega-3 PUFA that competes with AA for enzymatic pathways and is also a substrate for distinct lipid mediators (including less prothrombotic eicosanoids and pro-resolving mediators)
The ratio is calculated by dividing the AA content of a blood sample by the EPA content, with a higher AA:EPA corresponding to a lower relative EPA status.
AA and EPA are both metabolized to eicosanoids and the two compounds compete for key cyclooxygenase and lipoxygenase enzymes. Because AA is converted primarily into pro-inflammatory eicosanoids and EPA is converted into anti-inflammatory eicosanoids, the EPA:AA ratio has been proposed as a marker of chronic inflammation (Nelson & Raskin, 2019).
While the AA:EPA ratio is often referred to as a marker of inflammation, it is better conceptualized as a biomarker of omega-3 vs omega-6 long-chain PUFA balance, which may influence inflammatory and thrombotic pathways indirectly rather than measuring systemic inflammation directly. The AA:EPA ratio is considered a more sensitive version of the omega-6:omega-3 ratio, as it better accounts for the downstream metabolites of omega-6 and omega-3 parent compounds (linoleic acid and alpha-linolenic acid respectively).
Nomenclature: Although some laboratories report the AA:EPA ratio, most scientific literature reports the inverse ratio (EPA:AA ratio), where the AA:EPA = 1/(EPA:AA).
Conclusion
Chronic inflammation is increasingly recognized as a common pathogenic pathway in the development and progression of multiple chronic diseases that contribute to excess morbidity and mortality. Although currently available biomarkers reflect systemic rather than local tissue inflammation, and no single test provides a complete picture of inflammatory status, a focused panel can still provide clinically useful and actionable information. Based on the available evidence, as well as considerations of actionability and feasibility, hsCRP, fibrinogen, ferritin, NLR, WBC, and AA:EPA when available appear to offer the most useful combination of clinical relevance and practicality for inclusion in the NiaHealth inflammation panel.
Our research standards & process
At NiaHealth, we do not make decisions first and look for evidence later. The entire process — from which tests we offer, to how we interpret results, to the recommendations we make — is grounded in clinical evidence from the ground up. Our research team is continually reviewing the literature to make sure the information we provide reflects current medical evidence. And frankly, we don’t think “trust us” should be the standard here. We think you should be able to see the process for yourself. Learn more here.
