How to tell if you have low-grade chronic inflammation (and which markers to ask for)

Acute inflammation announces itself. The low-grade kind doesn't

A twisted ankle, a bad tooth, the flu. Heat, pain, swelling, redness. Acute inflammation is loud, it has a beginning and an end, and above all it's useful: it's the body repairing itself. When the job is done, it shuts off on its own.

The low-grade version runs the same machinery at a different scale. A small, sustained activation with no local signs to give it away. So it doesn't show up as inflammation — it shows up as something else: fatigue that rest doesn't fix, slower recovery after training, digestion that has changed, sleep that doesn't restore, vague aches, a head that won't clear.

None of those symptoms is specific. Every one of them has a hundred other possible explanations. They're a good reason to book an appointment, not a diagnosis, and that's precisely why blood work enters the picture.

The markers usually ordered, and what each one measures

Start with what none of them does: measure "your inflammation". There is no such number. What exists are indirect signals, each with its own blind spot.

The list is here so you know what's being discussed — not so you can walk into a lab and order the lot. Which tests, in what order, and at what moment is already a clinical decision, and it's as much part of the interpretation as the result itself.

• hs-CRP (high-sensitivity C-reactive protein). Not the same test as the standard CRP your GP orders for a suspected infection — same protein, finer resolution. It's made by the liver and rises with any inflammatory stimulus; the high-sensitivity version picks up the small variations that matter when there's no obvious infection. Very sensitive, barely specific: inflamed gums move it as readily as a sustained process does.
• Neutrophil-to-lymphocyte ratio. Not a separate test, and you don't need to request it: it's calculated by dividing two values already sitting in any full blood count. It reflects the balance between two arms of your defences and shifts with acute infection, with sustained stress and with hard training. Cheap to get, and extremely easy to over-read.
• Ferritin. It measures iron stores, but it's also an acute-phase reactant: it climbs when there's inflammation. High ferritin can mean stored iron, inflammation, or both at once, and telling them apart means looking at iron, transferrin and transferrin saturation from the same draw. Read alone, it misleads.
• The surrounding ground. Full blood count, fasting glucose and insulin, lipid profile, liver function, thyroid, vitamin D. None of these is an inflammation marker, but they're the context in which a high value gets explained — or ruled out.

What a high marker does not prove on its own

A value above your lab's range tells you one thing, and only one: that on the day of the draw there was an inflammatory stimulus somewhere in your body. It doesn't tell you where. It doesn't tell you since when. It doesn't tell you why. And it doesn't tell you whether it matters.

It also can't separate a trivial cause from a meaningful one. Last week's cold, a dental infection, an injury, a hard session two days earlier, smoking, pregnancy, certain medications — all of them lift that number exactly the way a chronic process does. The marker doesn't know where it came from.

And it isn't a severity scale, in either direction: a normal result doesn't certify that nothing is wrong. Add that the number itself fluctuates — the same person, nothing changed, gives different values on two draws — and that every lab has its own assay and its own reference range. That's why you won't find cut-off figures on this page. Out of context they mean nothing, and publishing them here would be irresponsible.

Context: when the blood was drawn, and what you'd been doing

A number with no person behind it isn't information. The same value can be noise in a thirty-year-old who ran a long race the previous weekend, and worth a serious conversation in a fifty-five-year-old who sleeps badly, has been gaining weight around the middle, and has been creeping upwards across their last few tests.

Before anything gets interpreted, there are questions worth more than the result: what infections you've had in recent weeks, what medication you take, how much and how hard you train, how you sleep, whether you smoke, where you were in your cycle. A single isolated data point is almost always read wrong. A trend is read far better.

Which is why old blood work is worth so much. The panel from three years ago, sitting in a drawer, can be more useful than last week's — it's the one that turns a number into a trajectory.

What to do with the information

A marker is a clue. No more than that, and no less. A clue is for aiming the next question, not for closing the case, and certainly not for hunting a diagnosis online at two in the morning. The person who can make it useful is a doctor with your full history in front of them.

In consultation the result stops being a loose number: it goes next to what you describe, what the examination shows, and the rest of your blood work. From there you decide what's next — sometimes that's repeating it in a few weeks, sometimes looking in a different direction, and sometimes doing nothing. That third option is an answer too.

This is the work we do in Integrative Health, with Clinical Psychoneuroimmunology as our reference approach: treating the cause rather than chasing the value. We're at Méndez Núñez 12, between Plaza Nueva and Sierpes in central Seville. If you come, bring every previous test you have.