Inflammation and CRP Glossary

Plain-English definitions of the terms you meet while learning about inflammation, C-reactive protein, and the habits that move them.

Inflammation is the immune system's response to injury, infection, or irritation, helpful in the short term and harmful when it lingers. C-reactive protein (CRP) is a protein the liver releases into the blood when inflammation is present, which makes it one of the most widely used markers for tracking it. This glossary defines the terms you will meet while reading about both, in plain English, with links to deeper articles where we have them.

A

Acute inflammation

Acute inflammation is the body's short-term response to injury or infection, with redness, heat, swelling, and pain that usually fade within days. It is a normal and protective process. Problems start when inflammation does not switch off.

Acute-phase reactant

An acute-phase reactant is a protein whose blood level rises or falls quickly when inflammation begins. C-reactive protein, ferritin, and fibrinogen are common examples. Labs measure them to gauge how much inflammation is present.

Adaptive immunity

Adaptive immunity is the slower, targeted arm of the immune system that learns to recognize specific threats. It relies on T cells and B cells and produces antibodies and memory that make later responses faster.

Adipokine

An adipokine is a signaling molecule released by fat tissue. Leptin and adiponectin are examples. Excess visceral fat shifts adipokine output toward signals that promote inflammation.

Advanced glycation end products (AGEs)

Advanced glycation end products form when sugars bond to proteins or fats, either inside the body or in foods cooked at high heat. They build up with age and high blood sugar and can trigger inflammatory signaling.

Anti-inflammatory diet

An anti-inflammatory diet is an eating pattern built around vegetables, fruit, legumes, whole grains, fish, nuts, and olive oil, with little added sugar, refined flour, or processed meat. It is a style of eating rather than a strict plan.

Antioxidant

An antioxidant is a molecule that neutralizes free radicals before they damage cells. The body makes some, such as glutathione, and gets others from food, such as vitamin C, vitamin E, and polyphenols.

Autoimmune disease

An autoimmune disease is a condition in which the immune system attacks the body's own tissues. Rheumatoid arthritis, type 1 diabetes, and lupus are examples, and most involve ongoing inflammation.

Autoimmunity

Autoimmunity is the loss of the immune system's ability to tell self from non-self, so it reacts against the body's own cells. It can exist at a low level without causing a named disease.

B

Baseline

A baseline is your usual level of a measurement when nothing unusual is going on. Knowing your baseline is what makes a later rise or fall meaningful. Several readings taken over calm weeks give a better baseline than one.

Biomarker

A biomarker is a measurable sign of a biological state, such as a protein level, a blood pressure reading, or a resting heart rate. CRP is a widely used biomarker of inflammation.

C

Chronic inflammation

Chronic inflammation is a low-grade immune response that persists for months or years instead of resolving. It often has no obvious symptoms and is linked with heart disease, type 2 diabetes, and other long-term conditions.

Circadian rhythm

The circadian rhythm is the body's roughly 24-hour internal clock that times sleep, hormone release, and immune activity. Irregular schedules and late light exposure disrupt it, and disruption is associated with higher inflammatory markers.

Cortisol

Cortisol is the main stress hormone, released by the adrenal glands. In short bursts it dampens inflammation, but when it stays high for long periods cells become less responsive to it and inflammation can rise.

C-reactive protein (CRP)

C-reactive protein is a protein the liver releases into the blood when inflammation is present anywhere in the body. Its level rises within hours of a trigger and falls as inflammation resolves. It is one of the most common lab markers of inflammation.

Curcumin

Curcumin is the yellow compound in turmeric that has been studied for anti-inflammatory effects. It is poorly absorbed on its own, so supplements often pair it with black pepper extract or fats.

Cytokine

A cytokine is a small protein that immune cells use to send messages to each other. Some cytokines turn inflammation up, others turn it down. Interleukin-6 and TNF-alpha are well-known pro-inflammatory cytokines.

E

ESR (erythrocyte sedimentation rate)

ESR measures how fast red blood cells settle to the bottom of a tube in one hour. Inflammatory proteins make cells clump and sink faster. It is an older, slower-moving marker than CRP and is still used alongside it.

F

Ferritin

Ferritin is the protein that stores iron in cells, and a blood test for it is the usual way to check iron stores. Because it is also an acute-phase reactant, ferritin can read high during inflammation even when iron is normal.

Fibrinogen

Fibrinogen is a clotting protein made by the liver that also rises with inflammation. High fibrinogen is associated with blood that clots more readily, which is one reason inflammation and heart risk are connected.

Free radical

A free radical is an unstable molecule with an unpaired electron that can damage proteins, fats, and DNA. The body produces free radicals during normal metabolism and immune activity, and antioxidants keep them in check.

G

Gut microbiome

The gut microbiome is the community of trillions of bacteria and other microbes living in the digestive tract. A diverse microbiome supports the gut lining and trains the immune system, while an unbalanced one is linked with inflammation.

H

HIIT (high-intensity interval training)

HIIT alternates short bursts of hard effort with recovery periods. A single session raises inflammatory markers for a day or so, while regular training over weeks is associated with lower resting inflammation.

Homocysteine

Homocysteine is an amino acid produced when the body processes protein. High levels, often tied to low folate or B12, are associated with blood vessel damage and are sometimes measured alongside CRP.

HPA axis

The HPA axis is the hypothalamus, pituitary, and adrenal glands working as a chain to control the stress response and cortisol release. Long-term stress can throw this system off balance and weaken its normal brake on inflammation.

hs-CRP (high-sensitivity CRP)

hs-CRP is a more sensitive laboratory assay for C-reactive protein that can measure the low levels seen in people without an obvious infection or injury. Clinicians use it to look at low-grade inflammation. It measures the same protein as a standard CRP test, only with finer resolution at the low end.

I

Immune system

The immune system is the network of cells, tissues, and signaling molecules that defends the body against infection and repairs damage. Inflammation is one of its main tools.

Inflammaging

Inflammaging is the slow, chronic rise in low-grade inflammation that tends to come with age. It is thought to contribute to many age-related conditions, and lifestyle factors can speed it up or slow it down.

Inflammation score (Sensa)

The Sensa inflammation score is a 0 to 100 number produced by the Sensa app after you spit into the vial, wait for the color change, and scan it, with a result in about 15 minutes. The score falls into one of three tiers: In range, Worth watching, or Time to reset. It is a general wellness tracking tool, not a medical diagnosis.

Innate immunity

Innate immunity is the fast, built-in first line of defense that responds the same way to any threat. It includes physical barriers like skin, cells such as neutrophils and macrophages, and the inflammatory response itself.

Insulin resistance

Insulin resistance is when cells stop responding well to insulin, so the pancreas has to make more to keep blood sugar normal. It is closely tied to visceral fat and chronic inflammation, and it often precedes type 2 diabetes.

Interleukin-6 (IL-6)

Interleukin-6 is a cytokine released by immune cells, fat tissue, and muscle. It is the main signal that tells the liver to produce CRP, which is why the two often rise together.

L

Lateral flow / colorimetric test

A lateral flow test moves a liquid sample along a strip where a line or color appears if a target substance is present. A colorimetric test produces a color change whose shade corresponds to how much of the target is in the sample. Sensa uses a color change in its vial that you scan with the Sensa app.

Leaky gut (intestinal permeability)

Leaky gut, or increased intestinal permeability, is a weakening of the tight seals between cells in the gut lining. Bacterial fragments and food particles can then pass into the bloodstream and provoke an immune response.

Leptin

Leptin is a hormone made by fat cells that tells the brain how much energy is stored and reduces appetite. With excess body fat, the brain can become resistant to leptin, and high leptin levels also promote inflammation.

M

Macrophage

A macrophage is a large immune cell that engulfs bacteria, dead cells, and debris. Macrophages also release cytokines, and those lodged in fat tissue are a major source of the low-grade inflammation seen with obesity.

Mediterranean diet

The Mediterranean diet is an eating pattern based on vegetables, fruit, legumes, whole grains, olive oil, fish, and moderate wine, with little red meat or sweets. It is the best-studied diet for lowering inflammatory markers.

Metabolic syndrome

Metabolic syndrome is a cluster of conditions that occur together: a large waist, high blood pressure, high blood sugar, high triglycerides, and low HDL cholesterol. Chronic inflammation runs through all of them.

mg/dL

mg/dL stands for milligrams per deciliter and is another unit used to report CRP, mostly in older or US-based lab reports. One mg/dL equals 10 mg/L, so check the unit before comparing two results.

mg/L

mg/L stands for milligrams per liter and is the most common unit for reporting CRP in blood. A standard CRP test and an hs-CRP test both report in mg/L but cover different ranges.

N

Neutrophil

A neutrophil is the most common type of white blood cell and the first to arrive at a site of infection or injury. Neutrophils destroy microbes and release signals that recruit other immune cells.

NF-kB

NF-kB is a protein complex inside cells that acts as a master switch for inflammation. When activated by stress, infection, or free radicals, it turns on the genes that produce inflammatory cytokines.

O

Omega-3 fatty acids

Omega-3 fatty acids are fats found in oily fish, flaxseed, and walnuts. The body converts them into molecules that help resolve inflammation, and higher intake is associated with lower inflammatory markers.

Omega-6 fatty acids

Omega-6 fatty acids are fats found in vegetable oils, seeds, and many processed foods. They are essential in moderate amounts, but a diet very high in omega-6 relative to omega-3 is thought to tilt the body toward inflammation.

Oxidative stress

Oxidative stress is an imbalance in which free radicals outnumber the antioxidants available to neutralize them. It damages cells and activates inflammatory pathways, and inflammation in turn produces more free radicals.

P

Polyphenols

Polyphenols are plant compounds found in berries, tea, coffee, cocoa, olive oil, and colorful vegetables. They act as antioxidants and feed beneficial gut bacteria, and diets rich in them are linked with lower inflammation.

S

Saliva testing

Saliva testing measures substances in spit rather than in blood. Collection needs no needles and can be done at home. Sensa is an at-home saliva wellness kit that uses this approach for inflammation tracking.

Short-chain fatty acids

Short-chain fatty acids such as butyrate are made when gut bacteria ferment dietary fiber. They feed the cells of the gut lining, strengthen the gut barrier, and calm immune activity.

Sleep debt

Sleep debt is the gap between the sleep you need and the sleep you get, built up over days or weeks. Even moderate sleep debt raises inflammatory markers such as CRP and IL-6.

T

TNF-alpha

TNF-alpha, or tumor necrosis factor alpha, is a powerful pro-inflammatory cytokine released mainly by macrophages. It drives fever and tissue inflammation, and several autoimmune medications work by blocking it.

Trend tracking

Trend tracking means looking at how a measurement changes across many readings rather than judging a single number. For inflammation, the direction over weeks tells you more than any one result.

V

Vagus nerve

The vagus nerve is the long nerve connecting the brain to the heart, lungs, and gut. It carries signals that tell immune cells to reduce cytokine release, a pathway called the inflammatory reflex.

Visceral fat

Visceral fat is the fat stored deep in the abdomen around the organs, as opposed to the fat under the skin. It is metabolically active and releases inflammatory cytokines, which makes it a stronger inflammation driver than body weight alone.

W

White blood cells

White blood cells, or leukocytes, are the immune system's circulating cells. Neutrophils, lymphocytes, and monocytes are the main types, and a high count is a general sign of infection or inflammation.

Z

Zone 2 training

Zone 2 training is steady aerobic exercise at an easy pace where you can still hold a conversation. Done regularly, it improves metabolic health and is associated with lower resting inflammatory markers.

Want to see where you stand? Sensa is an at-home saliva wellness kit that gives you a 0 to 100 inflammation score in about 15 minutes, so you can track your trend over time. Get your Sensa kit, or start with the basics in What is CRP?

This glossary defines 55 terms and was last updated on October 27, 2026.