Iron deficiency without anaemia: the stage that gets missed

A woman of thirty is exhausted. Breathless climbing stairs, losing hair, unable to concentrate by mid-afternoon.

Her haemoglobin is 12.1, which her report marks as normal. She is told she is fine and that she should sleep more.

She may well be iron deficient, and the test that would show it was not done.

This article is about that stage, because it is common, it has real symptoms, and it is the single most frequent diagnostic gap in women’s health in India.

This is information, not medical advice. Do not start iron without testing. Iron overload is harmful, and in an adult man or post-menopausal woman the cause must be investigated rather than just corrected.

Iron deficiency happens in stages

This is the whole explanation, and it is not complicated.

Stage 1, iron depletion. Stores are being drawn down. Ferritin falls. Haemoglobin is entirely normal.

Stage 2, iron-deficient erythropoiesis. Stores are empty, and red cell production is beginning to be constrained. Haemoglobin may still read within the reference range, perhaps at the lower end.

Stage 3, iron deficiency anaemia. Haemoglobin finally drops below the range.

So haemoglobin is a late marker. By the time it falls, the deficiency has been present for a long time.

And the symptoms do not wait for stage 3. Fatigue, poor exercise tolerance and hair shedding are reported in the earlier stages, before anaemia appears.

Which means “your haemoglobin is normal, so it isn’t iron” is a conclusion drawn from a test that cannot see the problem yet.

What ferritin is, and how to read it

Ferritin is the protein that stores iron. Measuring it in blood gives an estimate of your iron stores.

It falls first, which is exactly why it is the useful test here.

And the practical difficulty: laboratory reference ranges for ferritin are wide, often starting somewhere around 10 to 15 ng/mL. So a result of 13 is printed as “normal”.

But the threshold for symptoms appears to be higher than the bottom of the range. There is genuine debate in the literature about where the cut-off should sit, and different authorities propose different figures, but there is reasonable agreement that a ferritin in the low teens or twenties is inadequate, particularly in someone with symptoms, and many clinicians treating fatigue or hair loss aim considerably higher.

So the practical instruction is specific: ask for the number, and take the number to your doctor. Do not accept “normal” as the answer, and ask what they consider adequate in the context of your symptoms.

The two things that distort ferritin

Worth knowing, because both cause misreadings.

1. Inflammation raises ferritin.

Ferritin is an acute-phase protein, it goes up with infection, inflammation, chronic disease and liver disease.

So a normal-looking ferritin during an illness can conceal a real deficiency. This is why doctors often check CRP alongside it: if CRP is raised, the ferritin may be falsely reassuring.

2. A recent iron supplement or transfusion raises it temporarily.

And one more worth knowing: in thalassaemia trait, which is common in parts of India, the blood picture resembles iron deficiency, small red cells, but the iron may be normal or high. Giving iron in that situation is not helpful and can be harmful. This is a real diagnostic trap and it is why characterising anaemia matters rather than assuming.

The symptoms of the stage before anaemia

These are real, reported, and routinely attributed to something else:

• Fatigue, the commonest, and the most dismissed
• Reduced exercise tolerance, and breathlessness on exertion
• Hair shedding, diffuse, all over
• Poor concentration and memory, and mental fogginess
• Headaches
• Dizziness
• Feeling cold
• Restless legs, a recognised association, and one people never connect
• Brittle nails, and in advanced cases spoon-shaped nails
• Sore tongue, mouth ulcers, cracks at the corners of the mouth
• Reduced work and study performance
• Low mood and irritability
• And pica, a craving for ice, clay, chalk or raw rice. This is an odd, specific and well-recognised sign, and anyone who has it should be tested

And in children and adolescents: effects on attention and school performance, which is why this matters beyond how someone feels.

Who should be tested even without anaemia

• Any woman with unexplained fatigue
• Diffuse hair shedding
• Heavy periods, and most women do not know theirs are heavy
• Vegetarians and vegans
• Adolescent girls
• Pregnancy, and after delivery
• Blood donors, regularly
• Athletes, particularly female endurance athletes
• Anyone on long-term PPIs, acid aids iron absorption
• Coeliac disease or other malabsorption
• Restless legs syndrome
• Pica
• Chronic kidney disease, or heart failure, where iron deficiency is specifically looked for

How to read your own report

Practically, since reports are handed over without explanation.

Look for:

Haemoglobin, the headline, and the late marker.

MCV, mean red cell volume. Low suggests iron deficiency or thalassaemia trait; high suggests B12 or folate deficiency.

RDW, variation in red cell size. Often raised early in iron deficiency.

Ferritin, the number that matters here. Ask for it by name; it is frequently not included in a routine panel and has to be requested.

CRP, to interpret ferritin.

And if your doctor orders more: transferrin saturation, serum iron and TIBC together give a fuller picture, and soluble transferrin receptor is sometimes used because it is not affected by inflammation.

What a typical early iron deficiency looks like: haemoglobin normal or low-normal, MCV low-normal or low, RDW raised, ferritin low, CRP normal.

And then the question that matters most

Why are you iron deficient?

In a menstruating woman, heavy periods are the commonest answer, and heavy bleeding is treatable. Hormonal options and the progesterone intrauterine device among them, with fibroids and adenomyosis identifiable. Correcting iron while the loss continues is refilling a leaking bucket.

Other causes: vegetarian diet with poor absorption, pregnancy, coeliac disease, H. pylori, hookworm, long-term NSAIDs, and long-term PPIs.

And in an adult man or a post-menopausal woman: iron deficiency is not assumed to be dietary. The default assumption is gastrointestinal blood loss, and investigation, including endoscopy and colonoscopy where indicated, is how ulcers and bowel cancers are found.

Giving iron without that investigation is the serious error in this condition.

Correcting it

Dose and form are your doctor’s decision. A few things worth knowing, because they determine whether you finish the course:

Alternate-day dosing is better absorbed and better tolerated than twice daily, because a dose raises hepcidin and blunts absorption for roughly a day. Worth raising.

Ferrous bisglycinate is gentler than ferrous sulphate if side effects are the barrier; sulphate is cheapest with the most evidence.

Vitamin C with it, lemon, amla, markedly improves absorption.

Away from tea, coffee, milk, calcium and thyroid medication.

Black stools are expected. Black tarry stools with pain are not.

And continue past normal haemoglobin, usually about three months further, to refill ferritin. In this condition ferritin was the thing you were treating, so stopping when haemoglobin normalises guarantees recurrence.

Intravenous iron exists for people who cannot absorb or tolerate oral iron, and it is now routine.

Realistic timeline: haemoglobin begins rising within weeks; symptoms including hair shedding and fatigue take months, because of how slowly stores refill and how long the hair cycle is.

What a product can and cannot claim

We manufacture in this category, so the boundary matters.

What is sayable: iron’s recognised role in normal red blood cell and haemoglobin formation and in the reduction of tiredness and fatigue; vitamin C’s role in increasing iron absorption; the recognised roles of folate and B12.

What is not: treats anaemia, cures iron deficiency, raises haemoglobin, or treats fatigue as a condition. These are medicinal claims and we decline artwork that makes them.

And the honest point about this category: iron supplements genuinely work, for a genuinely common deficiency. And they are the wrong first step. The first step is a ferritin test, because without it you do not know whether you need iron, how much, or for how long, and because in some people iron is the wrong treatment entirely.

So the most useful thing we can tell a customer is: ask for ferritin. That sentence sells no product and it is the one that changes outcomes.

The short version

1. Iron deficiency has stages. Ferritin falls first; haemoglobin is a late marker.
2. You can be iron deficient with a normal haemoglobin, and have real symptoms.
3. Ask for ferritin by name. It is often not in a routine panel.
4. A ferritin of 13 prints as “normal” and is not adequate with symptoms. Take the number to your doctor.
5. Inflammation raises ferritin, check CRP alongside, or a real deficiency can be masked.
6. Thalassaemia trait mimics iron deficiency and is common in parts of India. Iron is not the answer there.
7. Symptoms of the early stage: fatigue, breathlessness on stairs, hair shedding, poor concentration, feeling cold, restless legs, and craving ice or clay.
8. MCV low and RDW raised with normal haemoglobin is a pattern worth noticing.
9. Ask why. Heavy periods are commonest, and treatable.
10. In a man or post-menopausal woman, the gut is investigated. Iron without that is the serious error.
11. Alternate-day dosing, vitamin C with it, tea an hour away.
12. Continue about three months past normal haemoglobin, ferritin was the target.
13. Symptoms take months to improve, not weeks.

Composition detail: Femino 360. Related: why iron deficiency is so common in Indian women, iron supplements that do not cause constipation, and iron deficiency and hair fall.