Ferritin 8: what your result means

How it works

Ferritin is the protein that stores iron, and the blood level broadly tracks how much iron the body holds in reserve. Because stores are drawn down before red blood cell production is affected, ferritin falls first, often months before haemoglobin moves, which is why a person can have depleted iron with a blood count still printed as normal. Ferritin is also an acute-phase protein: infection, inflammation and higher body weight push the number up, which can hide genuinely low stores. The number is therefore read alongside symptoms, CRP where available, and the rest of the iron panel rather than in isolation.

Guideline positions

NICE guidance classes adult ferritin below 30 ug/L as iron deficiency, while the WHO threshold of 15 ug/L marks severely depleted stores, and many UK laboratory reference ranges still flag results only below the lower cut-off. This gap between the reference range and the guideline threshold is why results in the teens and twenties are often reported as normal yet meet the NICE definition of deficiency. UK practice for confirmed deficiency centres on identifying the cause with a GP, dietary iron, and supplementation where appropriate, with a repeat test typically 8 to 12 weeks after any change.

Practical framework

Your ferritin of 8 ug/L sits in the lowest band: 7 under the WHO severe-depletion threshold of 15 ug/L and 22 under the NICE deficiency cut-off of 30. Crossing 15 is the first marker of progress on a retest; the guideline target is clearing 30 and continuing upward.

A ferritin below 15 ug/L meets the strictest definition of iron deficiency in use, the WHO threshold, and sits well under the NICE cut-off of 30, so this is a result to take to your GP rather than manage alone. The first step is establishing why stores are this low, since the cause, most commonly menstrual or other blood loss, low dietary iron, or absorption problems, decides what correction looks like. Fatigue, breathlessness on exertion, hair shedding, restless legs at night and reduced concentration are the symptoms most consistently linked to stores at this level, and they can be present even when haemoglobin is still in range. Once a GP has assessed the cause, evidence supports restoring stores through dietary iron and supplementation where advised, with vitamin C taken alongside supporting absorption and tea or coffee kept away from iron by an hour or two. A repeat test at 8 to 12 weeks shows whether stores are rebuilding; symptom change usually lags the number.