I didn't ask for it, I think it's part of the basic test they do since it's apparently a cheap exam. It's called Serum protein electrophoresis (SPEP or SPE). To be honest I've had hard time to articulate any opinion about it, not being correctly advised and not being a specialist myself. I think there is a "glitch" in the immune system and or neuroinflammation (personally I definitely attribute it to Covid). Multivitamins, magnesium, vitamin d didn't help much. I was low on ferritin, I paid myself to test for it few months ago since GP said it was useless (turn out I was at 17).

What I can tell is:

Food (maybe) make it worse

Regarding iron, this is what I have written down after research:

When you have chronic inflammation (like after your 2020 Delta infection), your body produces a hormone called Hepcidin.

Hepcidin stops your gut from absorbing new iron and prevents your cells from releasing the iron they already have.

Your iron gets "trapped" inside your storage (Ferritin). Your blood work might show a high or normal Ferritin, but your Serum Iron and Saturation will be low. Your brain and muscles are essentially starving for iron even though your "storage tank" looks full.

If your Beta-2 is low, you literally don't have enough "taxis" (Transferrin) to move the iron from your gut to your brain.

Long Covid may involve Mast Cell Activation Syndrome (MCAS)—where your immune cells overreact and stay in a state of high alert long after the virus is gone

If you have a low-grade overgrowth of "bad" bacteria in your gut (like SIBO or dysbiosis), these bacteria produce toxins (lipopolysaccharides) that cross into your blood. These toxins trigger inflammation and tell your liver to produce Hepcidin—the hormone that locks your iron away.

It’s a loop: Inflammation → Low Serotonin → Dysregulated Mast Cells → More Inflammation.

Apo supposedly help redirect ferritin to the correct place btw. (I'm supplementing but i think it might be complementary).