Ferritin Levels: Your Result vs the NIH and WHO Lines

Type the ferritin result from your blood test and say who it is for. You see it against every line the NIH and the WHO publish for that group — where the two disagree, both — and what an infection or inflammation does to the reading. Your lab’s range, and your doctor, have the last word.

45 ng/mL is

Above both iron-deficiency lines and not over the WHO’s 150 µg/L overload line

The lines for a woman or girl (10+) who has periods
Line	In the source’s words	Your 45

This is not medical advice and it does not diagnose anything. It shows where a number sits against published lines; what your result means for you depends on your other blood results, your history and your doctor.

NIH’s Office of Dietary Supplements says a serum ferritin “lower than 30 micrograms/liter (mcg/L) suggests iron deficiency, and a value lower than 10 mcg/L suggests IDA” (iron deficiency anemia). The WHO’s 2020 guideline puts the line at 15 µg/L for healthy people aged 5 and over, 70 µg/L with infection or inflammation, and an overload risk above 150 (women with periods) or 200 µg/L (men).

How to use it

Find “Ferritin” on your blood test and type the number. ng/mL, mcg/L and µg/L are the same number, so it does not matter which one your report prints. Pick who the test is for, and say whether there was an infection or inflammation when the blood was taken. You get every line the NIH and the WHO publish for that group, in their words, and where your result sits against each one — with MedlinePlus’s common lab range for adults beside them. It does not tell you what to take: that is the conversation with your doctor.

The lines, and why there are two sets

NIH ODS (Iron fact sheet, updated September 4, 2025) prints one pair of lines for everyone: under 30 mcg/L “suggests iron deficiency”, under 10 “suggests IDA”. The WHO guideline (2020) prints its lines by age, and a second column for people with an infection or inflammation, because ferritin rises with inflammation — in ODS’s words, it “can elevate serum ferritin concentrations”. The two sources disagree for a healthy adult (30 against 15), and a result between them is where they disagree, so the checker shows both and names each. Neither source is “the lab range”: MedlinePlus lists 30 to 400 ng/mL (male) and 13 to 150 ng/mL (female) as common measurements, and says “Normal value ranges may vary slightly among different laboratories.”

The WHO’s ferritin lines by group (µg/L = ng/mL), from its Table 1 and recommendation 1.3
Group	Iron deficiency, healthy	With infection or inflammation	Risk of iron overload
Woman or girl (10+) with periods	under 15	under 70	over 150
Woman (10+) with no periods	under 15	under 70	over 200
Man or boy (10+)	under 15	under 70	over 200
Girl, 5 to 9	under 15	under 70	over 150
Boy, 5 to 9	under 15	under 70	over 200
Child under 5	under 12	under 30	none printed
Pregnant, first trimester	under 15	none printed	none printed

With an infection or inflammation, the WHO’s overload line for adults who are not healthy is 500 µg/L. Its Table 1 prints 150 for all females; its recommendation 1.3 names “200 µg/L in men and non-menstruating women”, and the checker uses the recommendation’s words.

Common results, and where they sit

For a woman or girl (10+) with periods, no infection or inflammation
Ferritin	Where it sits
8 ng/mL	Under both sources’ iron-deficiency lines
12 ng/mL	Under both sources’ iron-deficiency lines
15 ng/mL	The two sources disagree here
25 ng/mL	The two sources disagree here
30 ng/mL	Above both iron-deficiency lines
45 ng/mL	Above both iron-deficiency lines
150 ng/mL	Above both iron-deficiency lines
180 ng/mL	Over the WHO’s iron-overload line

Worked examples

45 ng/mL, a woman with periods (the page’s example): above both iron-deficiency lines and not over the WHO’s 150 µg/L line — and inside MedlinePlus’s 13 to 150 ng/mL.
22 ng/mL, a woman with periods: under NIH ODS’s 30 mcg/L line, above the WHO’s 15 µg/L line. That is where the two sources disagree, and the page says so rather than choosing one.
50 ng/mL, the same woman with a chest infection: above ODS’s 30, but under the WHO’s 70 µg/L line for infection or inflammation — the number most people would call “normal” is the one inflammation can hide behind.
250 ng/mL, a man: over the WHO’s 200 µg/L line, yet inside MedlinePlus’s 30 to 400 ng/mL. The WHO’s own words are that ferritin “should not be used alone to identify risk of iron overload”.

Common mistakes

Reading a result taken during an infection as reassuring. NIH ODS: “although low serum ferritin levels indicate iron deficiency, these levels tend to be higher in patients with infection or inflammation.”
Taking the bottom of the lab range as the line. A report’s 13 ng/mL lower limit is not ODS’s 30, and MedlinePlus adds: “The lower the ferritin level, even within the normal range, the more likely it is that the person does not have enough iron stored in their body.”
Reading ferritin on its own. NIH ODS: “Often, hemoglobin concentrations are combined with serum ferritin measurements to identify IDA.” Your doctor reads it with the rest of the blood count.
Starting iron because of one number. Iron supplements have an upper limit, and a high ferritin has causes other than iron. Whether to take iron is your doctor’s call.

Frequently asked questions

What is a normal ferritin level?

MedlinePlus lists 30 to 400 ng/mL for males and 13 to 150 ng/mL for females as common measurements, and says ranges “may vary slightly among different laboratories”. NIH ODS adds that a ferritin lower than 30 mcg/L “suggests iron deficiency”. Your lab’s own printed range is the one your doctor will use.

What is the normal ferritin range for a woman?

MedlinePlus lists 13 to 150 ng/mL for females. The WHO puts iron deficiency under 15 µg/L for healthy women, and a possible overload risk over 150 µg/L in women with periods (200 µg/L after menopause). NIH ODS’s line for iron deficiency is 30 mcg/L.

What are normal ferritin levels by age?

The WHO splits its lines by age: under 12 µg/L suggests iron deficiency in a healthy child under 5, and under 15 µg/L from age 5 — including adults and people over 60, whose lines are the same. MedlinePlus and NIH ODS print no age split.

What is an ideal ferritin level?

No official source we read names an “ideal” ferritin. NIH ODS draws its iron-deficiency line at 30 mcg/L, and MedlinePlus notes that “the lower the ferritin level, even within the normal range, the more likely it is that the person does not have enough iron stored in their body”.

Why does inflammation change a ferritin result?

Ferritin rises with infection and inflammation, so a low iron store can read as normal. NIH ODS: inflammation “can elevate serum ferritin concentrations”. That is why the WHO uses a higher line — 70 µg/L from age 5, 30 µg/L under 5 — when there is infection or inflammation.

Is ng/mL the same as mcg/L?

Yes. 1 ng/mL is 1 µg/L (mcg/L), so a ferritin of 45 ng/mL is 45 mcg/L. NIH ODS writes mcg/L, the WHO µg/L and MedlinePlus ng/mL — the number does not change.

What ferritin level is too high?

The WHO says a ferritin over 150 µg/L in women with periods and over 200 µg/L in men and other women “may indicate a risk of iron overload”, and over 500 µg/L in adults who are not healthy. It also says ferritin “should not be used alone” — a high result is a call to your doctor.

Taking iron? When to take the tablet around your meals, coffee and calcium: the Iron Tablet Timing Planner. A reticulocyte count is one way a doctor sees the marrow answer it: the Reticulocyte Count Checker. The rest of an iron panel — the TIBC and the saturation it gives with your serum iron: the TIBC Level Checker.

Ferritin Level Checker