Ferritin 15 to 30: what your result means

How it works

A ferritin between 15 and 30 micrograms per litre is the result most often missed. The NICE guidance on iron deficiency sets adult iron deficiency at a ferritin below 30, yet many UK laboratory reports still only flag results below 15, a threshold that comes from older WHO reference data. So a number in this band is frequently printed with no flag beside it, read out as normal, while current UK guidance classes the same number as iron deficiency. This is one of the most common reasons people are told their bloods are fine while still feeling exhausted.

Guideline positions

NICE iron deficiency guidance and BSG 2021: adult iron deficiency at ferritin below 30 micrograms per litre. WHO ferritin guidance: below 15 ug/L consistent with deficiency in apparently healthy adults, which is where many laboratory flags still sit, and above 500 ug/L in adults who are unwell may indicate iron overload or other disease. BSG 2021: transferrin saturation read alongside ferritin, with below 20 percent alongside a ferritin of 30 or more consistent with iron deficiency. Ferritin is a positive acute-phase reactant, so inflammation raises it independently of iron stores.

Practical framework

A result in this band suggests raising it with your GP, particularly if you have symptoms, since guidance looks for the cause behind low iron alongside correcting the level. Where iron is appropriate, the evidence favours consistent daily intake with a vitamin C source and away from tea and coffee, with a retest around three months on to see whether stores are refilling. A raised CRP makes the ferritin unreliable, and a transferrin saturation below 20 percent strengthens the iron deficiency reading further.

You can read your own numbers against these thresholds with the free blood test result interpreter on this site. It runs entirely on your device, nothing is saved, and pasting your report fills the values in for you.