C-reactive protein, or CRP, is a protein produced by the liver in response to inflammatory signaling in the body. It rises when the immune system is activated, which makes it a valuable marker for identifying inflammation that is occurring beneath the surface. Traditional CRP tests detect moderate to high levels, usually seen with acute injury or infection. High sensitivity CRP, often written as hsCRP, is designed to measure very small elevations that reflect chronic, systemic, low grade inflammation. This level of precision is essential when we are evaluating cardiometabolic risk, longevity, and chronic disease activity.
Why high sensitivity testing matters
A standard CRP test cannot reliably detect inflammation below about 3 to 5 mg per L, which means it misses the subtle immune activation that drives many chronic conditions. hsCRP measures much lower concentrations, often down to 0.3 mg per L, which makes it far more useful for prevention based care.
Elevations in hsCRP often reflect endothelial irritation, metabolic dysfunction, oxidative stress, or chronic immune activation. These patterns occur long before symptoms are obvious.
This is why hsCRP has become central in cardiovascular prevention. Small, steady increases in hsCRP correlate with higher rates of myocardial infarction, stroke, and cardiovascular mortality. In some populations, hsCRP levels predict events as strongly as LDL cholesterol, and sometimes with greater accuracy.
Inflammation is the common denominator in chronic disease
Chronic inflammation is not isolated to one organ system. It affects the entire vascular tree, the gut, the brain, the metabolic environment, and the immune system. Persistent inflammatory signaling disrupts endothelial function, insulin signaling, mitochondrial efficiency, and neuroimmune communication. Over time, this contributes to the conditions we see rise across the lifespan, including:
- Atherosclerosis and cardiovascular disease
- Type 2 diabetes and insulin resistance
- Obesity and visceral adiposity
- Autoimmunity
- Neurodegeneration
- Chronic gastrointestinal dysfunction
- Hormone imbalances
- Mood disorders and cognitive decline
Inflammation acts like a background noise in the body. When it is elevated, it amplifies risk across multiple systems. When it is quieted, metabolic and cardiovascular stability improve.
Functional medicine uses hsCRP to identify systemic inflammation and guide deeper investigation
In functional medicine, hsCRP helps map the physiologic terrain. It is never interpreted in isolation. Instead, it is integrated with metabolic & cardiovascular markers, immune markers, hormone data, gut health insights, and environmental inputs. We use hsCRP to answer several key questions:
1. Is there evidence of systemic inflammation?
Even a mild elevation can point toward metabolic stressors, environmental exposures, sleep disruption, chronic infections, gastrointestinal imbalances, or nutrient deficiencies.
2. What is the likely root cause?
hsCRP does not diagnose a cause, but it directs clinical reasoning. Elevated levels prompt deeper work in areas such as blood sugar regulation, visceral adiposity, oral health, chronic immune activation, toxin exposure, and stress physiology.
3. Is a treatment plan improving inflammatory load?
hsCRP is a reliable trend marker over time. It can respond to dietary change, physical activity, sleep, weight changes, microbiome repair, stress reduction, and mitochondrial support. It is also responsive to targeted therapies that address inflammation at the vascular and cellular level.
4. Does the patient have residual inflammatory risk?
Even when LDL or ApoB is well controlled, inflammation may persist. This residual risk is now being recognized as a critical driver of cardiovascular events.
Mainstream cardiology officially acknowledges inflammation as a treatment target
The 2025 American College of Cardiology scientific statement marks a major shift. The ACC now identifies inflammation as a primary therapeutic target in cardiovascular disease, not a secondary factor or optional add on.
Key points from the statement include:
- hsCRP should be a standard biomarker for both prevention and treatment decisions.
- Lifestyle based interventions such as Mediterranean and DASH nutrition patterns, regular physical activity, smoking cessation, and healthy weight maintenance significantly lower hsCRP.
- Pharmacologic tools are expanding. Low dose colchicine has FDA approval for reducing cardiovascular events, and more anti inflammatory agents are in development.
The message is clear. Preventing and treating heart disease requires identifying and treating inflammation. This is a major acknowledgement from conventional cardiology and reinforces a foundational principle long used in functional medicine.
Bringing it all together
hsCRP is one of the most practical tools for assessing low grade, systemic inflammation and for tracking response to treatment over time. It offers insight into vascular health, metabolic status, immune activity, and overall physiologic resilience. With the ACC now recognizing inflammation as a central therapeutic target, hsCRP has officially moved from optional to essential.
Functional medicine practitioners have used this approach for years. Measuring inflammation, locating the source, and treating the underlying drivers leads to better outcomes and improved long term health. This is how preventive cardiometabolic care continues to evolve, and hsCRP remains one of the most clinically useful markers in that process.
Resources
- A. Jackson, MD, FACC, E. (2025). Women’s Health Study: hs-CRP, LDL-C, Lp(a), and 30-Year CV Outcomes – American College of Cardiology. American College of Cardiology. https://www.acc.org/Latest-in-Cardiology/Journal-Scans/2024/08/29/19/09/inflammation-cholesterol-esc-2024
- Mo, J., Chen, Z., Xu, J., Wang, A., Meng, X., Zhao, X., Li, H., Wu, S., & Wang, Y. (2020). The impact of the cumulative burden of LDL-c and hs-CRP on cardiovascular risk: a prospective, population-based study. Aging, 12(12), 11990–12001. https://doi.org/10.18632/aging.103365
- Hartley, A., Somayeh Rostamian, Kaura, A., Chrysostomou, P., Welsh, P., Cono Ariti, Sattar, N., Sever, P., & Khamis, R. (2025). The relationship of baseline high-sensitivity C-reactive protein with incident cardiovascular events and all-cause mortality over 20 years. EBioMedicine, 117, 105786–105786. https://doi.org/10.1016/j.ebiom.2025.105786
