What is anaemia?
Haemoglobin sits in your red blood cells and binds oxygen in the lungs, to release it where your body needs it. If haemoglobin falls, the transport capacity of your blood drops. The body catches that first: the heart pumps faster, breathing speeds up and proportionally more blood goes to the organs that ask hardest for oxygen. Precisely that compensation causes the familiar complaints, from palpitations to dizziness on standing up. The finding itself does not yet say why haemoglobin is low. For that you look at the blood count around it. MCV points the way: small red blood cells fit iron deficiency, large ones a deficiency of vitamin B12 or folate, and a normal MCV with a raised RDW fits a mixed picture. Ferritin, vitamin B12 and folate then complete the story, and the reticulocytes show whether the bone marrow is at least trying to make more. In adults iron deficiency is by far the most common cause, and that stage already exists for months before haemoglobin falls. After that come a deficiency of B12 or folate, an inflammation or chronic disease that inhibits production, and blood loss that goes faster than the bone marrow keeps up. Rare is accelerated breakdown or a bone marrow that itself makes too little.
Which blood values show anaemia?
Every value below has its own page with the reference ranges of four Dutch labs.
| Value | What it shows | Points here when |
|---|---|---|
| Hemoglobindefining | The oxygen-carrying protein itself. The value that decides whether there is anaemia. | low |
| Hematocrit | The share of red blood cells in your blood. Falls along with haemoglobin. | low |
| Erythrocytes | The number of red blood cells per litre. | low |
| MCV | The average cell size. Points to the cause: small towards iron, large towards B12 or folate. | abnormal |
| MCH | How much haemoglobin an average red blood cell carries. | low |
| RDW | How much cell sizes differ from each other. Rises when old and new cells mix. | high |
| Ferritin | The iron store. Low in anaemia caused by iron deficiency. | low |
| Vitamin B12 | Low in anaemia with large red blood cells. | low |
| Folate | The other vitamin behind large red blood cells. | low |
What are the symptoms of anaemia?
These complaints are described for anaemia in guidelines and research. None of them is exclusive to it: the same complaints fit many other explanations, and an abnormal value can exist without any of them.
A slowly developing anaemia can go unnoticed for a long time: the body adapts, until exertion makes the difference visible.
- Tiredness, especially during exertionin the guideline
Also described at iron deficiency, underactive thyroid, vitamin B12 deficiency, low testosterone.
- Looking pale, most of all in the facein the guideline
- Shortness of breath during exertionin the guideline
- Palpitations or a pounding heartin the guideline
- Dizziness, especially when standing up quicklyin the guideline
- Headachein the guideline
- Ringing in the earsin the guideline
A complaint points in more than one direction, and a measurement explains no complaint: blood testing shows where your values stand, the reading and the diagnosis belong with your GP. The complaint list follows the Dutch GP guideline on anaemia (NHG).
What causes anaemia?
Too little production
The bone marrow makes fewer red blood cells than the body needs. By far the most common route.
- Iron deficiency, the most common cause worldwide
- A shortage of vitamin B12 or folate
- Chronic disease or inflammation slowing production down
- A bone marrow disorder, rare
Blood loss
More red blood cells are lost than the bone marrow can replace.
- Heavy or prolonged menstruation
- Bleeding in the stomach or bowel, which is not always visible
- Surgery or childbirth
Accelerated breakdown
Red blood cells live shorter than the roughly one hundred and twenty days that are normal.
- Haemolytic anaemia, in which the immune system breaks down its own cells
- Inherited forms such as thalassaemia and sickle cell disease
What is anaemia confused with?
Each with the one value that tells the two apart.
Iron deficiency without anaemia
The store can already be empty while haemoglobin is still normal. A normal Hb therefore does not rule out iron deficiency; ferritin shows the store.
Distinguishing value: Ferritin
A shortage of vitamin B12 or folate
Gives the same anaemia, but MCV points the other way: red blood cells become larger instead of smaller.
Distinguishing value: MCV
Thalassaemia or carrying it
Here too the red blood cells are small, but the iron store is normal. A low MCV with a normal ferritin does not fit iron deficiency and has a different explanation.
Distinguishing value: Ferritin
What you do about anaemia
Find the cause first, because anaemia is a consequence. With small red blood cells and a low ferritin it is iron: eat iron-rich food daily, red meat, fish, legumes and green leafy vegetables with some vitamin C alongside, and replenish with tablets if the store is empty, for three to six months. With large red blood cells it is B12 and folate: more vegetables and legumes, less alcohol, and B12 from animal products or a supplement if you eat plant-based; a stomach that no longer absorbs B12 calls for injections or a high dose of tablets. Close the leak as well. Heavy periods are the most common reason in women and can be tempered with the pill or a coil; blood loss in stomach or gut that you do not see should be checked, certainly above fifty. With an inflammation or chronic disease that inhibits production, haemoglobin only recovers once that is tackled, and then iron alone does not help. Measure again after two to three months: haemoglobin rises within weeks once the cause is gone, and the reticulocytes show within a week whether the bone marrow is picking up the refill. A haemoglobin that does not rise means the cause has not yet been found.
From which hemoglobin does a lab call it low?
This is what the four largest Dutch labs publish themselves, side by side.
7.5 – 10.0mmol/L
Outside this range every lab calls it abnormal.
every lab calls 7.5 – 10.0 mmol/L normal. Outside that range every lab calls it abnormal.
Every age group per lab
| Lab | Group | Reference range |
|---|---|---|
| Unilabs(Saltro, Medlon, SHO, Atalmedial)2026 | Men 15+ | 8.5–11.0 mmol/L |
| Women 15+ | 7.5–10.0 mmol/L | |
| Star-shl2026 | Men 18+ | 8.5–11.0 mmol/L |
| Women 18+ | 7.5–10.0 mmol/L | |
| Certe2026 | Men 18+ | 8.5–11.0 mmol/L |
| Women 18+ | 7.5–10.0 mmol/L | |
| Clinical Diagnostics2026 | Men 11+ | 8.5–11.0 mmol/L |
| Women 11+ | 7.5–10.0 mmol/L |
How to get anaemia measured
- Fasting
- No fasting needed. Eating makes no difference to haemoglobin or the blood count.
- Material
- Venous blood, drawn at one of our collection points.
- Results
- Results within 24 hours of analysis, in the app.
- Referral
- No referral from a GP required.
- Which test
- The Iron & fatigue test (€99, single test) measures the values on this page.
- Where to draw
- You can draw at 250+ locations near you, no referral needed. See the locations
Frequently asked questions
From which Hb do you speak of anaemia?
Below 7.5 mmol/L in an adult woman and below 8.5 in a man. Over this limit there is unusually broad agreement, at all four labs, and the World Health Organization draws the same line in other units: 12 and 13 g/dL. The number says there is anaemia, not why; for that you read MCV and ferritin beside it.
Why do I read different haemoglobin values online than on my report?
Because the Netherlands measures haemoglobin in mmol/L and almost all foreign sources in g/dL. The same value therefore looks completely different: 7.5 mmol/L is about 12 g/dL, with a conversion factor of 1.61. Anyone who sets their Dutch report beside an American table compares two units and not two states of health. Always compare in the same unit, and with the band on your own report.
Is anaemia the same as iron deficiency?
No. Iron deficiency is about the store, anaemia about haemoglobin itself. The store runs out first and only then does haemoglobin fall, so iron deficiency without anaemia is common and is the stage in which you can still catch up with food. Conversely anaemia can also arise without an iron problem, through a deficiency of vitamin B12 or folate, an inflammation or blood loss.
What about anaemia in pregnancy?
In pregnancy it is mainly the blood plasma that increases, so haemoglobin dilutes and the value comes out lower by itself. That is why other, lower limits apply in pregnancy, and the midwife checks haemoglobin as standard. The need for iron rises sharply at the same time, so a low store beforehand almost always ends in a deficiency. The bands on this page apply outside pregnancy.
Can you have anaemia without noticing anything?
Yes, especially when it develops slowly. The body compensates a falling haemoglobin with a faster heartbeat and breathing, and gets used to the new level. Complaints then only stand out on exertion, or not at all. That is why anaemia regularly comes as a surprise from a blood test done for another reason, and why the blood count beside it matters more than how you feel.
Sources
- 1.NHG-Standaard Anemie. 2024. richtlijnen.nhg.org
- 2.Unilabs test directory, haemoglobin. 2026. bepalingenklapper.nl
- 3.Star-shl test directory, haemoglobin. 2026. star-shl.nl
- 4.Certe test directory, haemoglobin. 2026. bepalingenwijzer.certe.nl
- 5.Clinical Diagnostics test guide, Hb and MCV. 2026. clinicaldiagnostics.nl
This page explains what a result means. It is not a diagnosis and not treatment advice. Discuss complaints or an abnormal value with your doctor.
Read about our scientific approach