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Hematology

Haemoglobin: Normal Values and What a Low Hb Means

Hemoglobin is especially important for women, as menstrual blood loss can lead to lower levels over time. Understanding your hemoglobin helps you take proactive steps to maintain your energy, support your hormonal health, and feel empowered in managing your well-being.

Doctor's Assessment Included

Reference Ranges

Female
mmol/l
Low 7.5 Normal 10 High

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

Check your own value

What It Measures

Haemoglobin (Hb) is the iron-containing protein in your red blood cells that binds oxygen. It picks up oxygen in your lungs, carries it around your body, and takes carbon dioxide back on the return trip.

This test measures how much haemoglobin is present per litre of blood. In the Netherlands the result is usually reported in mmol/l; internationally g/dl is more common. The value is measured as standard within the complete blood count.

Because almost all the oxygen in your blood is bound to haemoglobin, this value tells you directly how much oxygen your blood can carry. Your doctor will therefore almost always assess haemoglobin together with haematocrit, the red cell count and MCV.

Why It Matters

A low haemoglobin means anaemia: your blood carries less oxygen, so you tire more quickly and become short of breath sooner during exertion. The most common cause is iron deficiency, but a lack of vitamin B12 or folate, blood loss (for example through heavy periods or the gut), a chronic illness or reduced kidney function can also lower the value.

A high haemoglobin is less common. Dehydration produces an apparently raised value because your blood is more concentrated. Smoking, time at high altitude, sleep apnoea and a bone marrow disorder can genuinely increase red cell production.

The value on its own does not tell you the cause. Only in combination with MCV, ferritin and the rest of your blood count does it become clear which form of anaemia is present and what lies behind it.

When to Test

Haemoglobin is measured as standard whenever you have a complete blood count. That is often done for persistent fatigue, pallor, breathlessness on exertion or dizziness.

The value is also useful to follow while you are being treated for anaemia, if you have heavy periods, or if you follow a diet that is low in iron.

For endurance athletes haemoglobin is relevant because it relates directly to oxygen transport and therefore to endurance. Test at rest and well hydrated where possible, because dehydration can artificially raise the result.

Symptoms

Low Levels

A low haemoglobin causes symptoms that fit anaemia: fatigue, reduced endurance, breathlessness on exertion, pale skin, cold hands and feet, headache or dizziness. The symptoms often develop gradually, so you can get used to them without noticing.

High Levels

A raised haemoglobin often causes no symptoms. With a strongly raised value you may notice headache, dizziness, a flushed complexion or itching after a hot shower. Because the blood becomes thicker, the risk of clot formation can increase, so a persistently raised value should be assessed by a doctor.

Lifestyle Tips

Dietary iron is the foundation: red meat, legumes, wholegrain products and dark leafy greens. Vitamin C with a meal improves the absorption of plant-based iron, while coffee and tea inhibit it.

Do not start iron supplements on your own initiative. Supplementing without a demonstrated deficiency is not useful and too much iron can be harmful; have your ferritin measured first.

Drink enough before a blood draw: dehydration concentrates your blood and can artificially raise the result. A persistently low or high value should always be investigated by a doctor, because the underlying cause matters more than the number itself.

Frequently Asked Questions

What does a low haemoglobin mean?
A low Hb means anaemia: your blood carries less oxygen. Iron deficiency is the most common cause, but blood loss, a lack of vitamin B12 or folate and chronic illness can also play a part.
What does a high haemoglobin mean?
Dehydration is usually the cause, because your blood is then more concentrated. Smoking, time at high altitude, sleep apnoea or a bone marrow disorder can genuinely increase red cell production.
What is the difference between haemoglobin and ferritin?
Haemoglobin shows how much oxygen your blood can carry right now. Ferritin reflects your iron stores. Ferritin can already be low while haemoglobin is still normal, so iron deficiency often begins before anaemia becomes visible.
Can training lower my haemoglobin?
Endurance athletes sometimes show a slightly lower Hb because blood volume increases and dilutes the haemoglobin. This is known as sports anaemia and is not a true iron deficiency, but genuine anaemia still needs to be ruled out.
Do I need to fast for a haemoglobin test?
Fasting is not needed for haemoglobin. It is sensible to be well hydrated, because dehydration can artificially raise the value.
How quickly does haemoglobin rise after iron deficiency is treated?
Once iron deficiency is treated, haemoglobin usually starts to rise within a few weeks, but replenishing the iron stores often takes several months. Your doctor decides when a follow-up measurement is useful.

Test Products

This marker is included in the following test panels.

Hemoglobin

€8,-