Inflammatory markers are blood tests that show how much inflammatory activity is running in the body — most commonly C-reactive protein, the erythrocyte sedimentation rate (ESR), fibrinogen, ferritin and interleukin-6 (IL-6). They are deliberately non-specific: a raised value says that something is inflamed, not what or where. In longevity work the interest is not the loud spike of an acute illness, but the quiet, permanently slightly-raised readings that track with biological aging — a pattern usually called inflammaging.
What it measures
Each marker reads a different point in the same response. C-reactive protein is an acute-phase protein made by the liver when IL-6 signals it to; it climbs within hours of an insult and clears within days, making C-reactive protein (CRP) the most responsive of the group. The ESR is indirect: the lab records how far red cells fall in a vertical tube in one hour, which increases when fibrinogen and other large proteins make them stack together. It moves slowly, over days to weeks. Fibrinogen is measured directly and is both a clotting factor and an acute-phase protein. Ferritin stores iron but also behaves as an acute-phase reactant, so a high result can reflect inflammation rather than iron overload. IL-6 is the upstream cytokine.
All come from an ordinary venous blood draw and none requires fasting. Labs sell them bundled as a panel of Inflammatory markers because no single one is informative alone.
Typical values
Reference intervals are set by each lab and depend on the assay, so read your own report rather than a table on the internet.
| Marker | Units | How it is commonly read |
|---|---|---|
| hs-CRP | mg/L | The widely used cardiovascular risk bands are under 1 (low), 1-3 (average) and above 3 (high). Above 10 usually signals an acute event and is repeated rather than scored. |
| ESR | mm/hour | The upper limit rises with age and is higher in women; a common rule of thumb puts the ceiling at age divided by two in men, and age plus ten divided by two in women. |
| Fibrinogen | g/L | Most labs report roughly 2-4 g/L as normal, with the exact interval set by the method. |
| Ferritin | ng/mL | Ranges differ substantially by sex, age and lab. Not an iron measure while anything else is inflamed. |
| IL-6 | pg/mL | No agreed clinical cut-off; results are assay-specific and the test is mostly used in research. |
Why it matters for longevity
In large observational cohorts, higher CRP and higher IL-6 are associated with all-cause mortality, cardiovascular events, frailty and dementia risk, and the association survives adjustment for the usual risk factors. IL-6 in particular drifts upward across the adult lifespan even in people who stay well.
Whether inflammation causes the damage or merely reports it is partly answered. Randomized trials of anti-inflammatory drugs in established coronary disease — canakinumab, which blocks interleukin-1 beta, and low-dose colchicine — reduced cardiovascular events, which argues that the inflammation itself does harm. That is not the same as showing that lowering your CRP number extends your life; no trial has tested that endpoint.
What changes it
The largest single lever is body fat, especially visceral fat: adipose tissue secretes IL-6, and weight loss lowers CRP in trials roughly in proportion to fat lost. Regular aerobic and resistance training is associated with lower markers, mostly through that same route. Stopping smoking, treating gum disease, fixing short or broken sleep and reducing chronic stress all push in the right direction. Diet helps modestly: fiber-rich and Mediterranean-style patterns and omega-3 intake lower CRP in trials by small amounts. Statins lower hs-CRP independently of their effect on cholesterol.
Some things you cannot control also matter. Age itself raises the baseline, and common variants in the CRP gene shift where your value sits without changing your risk. Any recent infection, injury, vaccination, hard session or autoimmune flare can lift a result for weeks — which is why a single high reading is retested before anyone acts on it.
Related reading
- Chronic Inflammation and Aging: Inflammaging
- Which Blood Tests Reflect Aging and How to Read Them
- Omega-3 and Longevity: Fish, Supplements, Evidence
- hs-CRP
Disclaimer. This article is for information only and does not replace medical advice. Talk to a qualified clinician before changing anything about your health.