Kabtafer Plus Medical Team · Last reviewed: 11 October 2026
Sources: WHO haemoglobin guideline (2024), WHO ferritin guideline (2020), JAMA 2025 review, BSG guideline (2021), NIH ODS and StatPearls: Beta Thalassemia.
The short answer
An anemia work-up usually has two parts: a full blood count (CBC), which shows whether you are anemic and how big your red cells are, and iron studies, which show whether your iron stores are low. Haemoglobin tells you if you have anemia; ferritin tells you if iron is the likely reason. Small red cells (low MCV) can come from iron deficiency or from thalassaemia trait, which is common in the UAE. Always read your results with your doctor, and use the reference ranges printed by your own lab.
Have your lab report? Use our free iron blood test checker →
Key points
- WHO defines anemia as haemoglobin below 12.0 g/dL in non-pregnant women and below 13.0 g/dL in men.
- MCV below about 80 fL means small (microcytic) red cells.
- Ferritin below 30 ng/mL, or transferrin saturation below 20%, suggests iron deficiency in clinical practice (JAMA 2025).
- Inflammation raises ferritin, so a normal result does not always rule out low iron.
- The Mentzer index (MCV ÷ RBC) is a quick hint, not a diagnosis.
- Your lab’s own reference ranges take precedence over general figures.
What is in a full blood count?
| Item | What it measures | What it can suggest |
|---|---|---|
| Hb (haemoglobin) | Oxygen-carrying protein in the blood | Low = anemia |
| RBC (red blood cell count) | Number of red cells | Often normal or high in thalassaemia trait, low in iron deficiency |
| MCV (mean cell volume) | Average size of red cells | About 80–100 fL is typical; below 80 fL = small cells |
| MCH (mean cell haemoglobin) | Haemoglobin per red cell | Low when cells are small and pale |
| RDW (red cell distribution width) | Variation in red cell size | High in iron deficiency; normal or mildly raised in thalassaemia trait |
MCV and RDW figures are guides only; reference ranges differ between labs (StatPearls).
Which haemoglobin level means anemia?
These are the WHO 2024 cut-offs for adults and pregnancy. More detail is on our anemia hub and anemia in pregnancy pages.
| Group | Anemia | Mild | Moderate | Severe |
|---|---|---|---|---|
| Non-pregnant women 15–65 | <12.0 g/dL | 11.0–11.9 | 8.0–10.9 | <8.0 |
| Men 15–65 | <13.0 g/dL | 11.0–12.9 | 8.0–10.9 | <8.0 |
| Pregnancy, 1st & 3rd trimester | <11.0 g/dL | 10.0–10.9 | 7.0–9.9 | <7.0 |
| Pregnancy, 2nd trimester | <10.5 g/dL | — | ||
What do iron studies show?
Ferritin
Ferritin reflects how much iron is stored in your body. It is the most useful single test for iron deficiency, and it falls before haemoglobin does. This is why many women have low ferritin with a normal blood count — see heavy periods and low ferritin.
Serum iron
Serum iron is the iron circulating in your blood at the moment of the test. It changes with recent meals and supplements, so on its own it is not a reliable guide to your stores.
Transferrin saturation (TSAT)
TSAT shows how much of the iron-carrying protein (transferrin) is loaded with iron. The JAMA 2025 review uses TSAT below 20%, alongside ferritin below 30 ng/mL, to identify iron deficiency.
Why are there different ferritin cut-offs?
You may see different numbers quoted because they are designed for different jobs. The WHO thresholds are set to define iron deficiency in apparently healthy people and populations. Clinical guidelines use higher cut-offs so that doctors miss fewer patients who would benefit from treatment. (Note: ng/mL and µg/L are the same unit.)
| Source | Cut-off | Purpose |
|---|---|---|
| WHO 2020 | <15 µg/L (age 5+, incl. adults; also 1st trimester); <12 µg/L under 5 | Iron deficiency in apparently healthy people |
| WHO 2020, with infection/inflammation | <70 µg/L (age 5+); <30 µg/L under 5 | Adjusts for inflammation |
| NIH ODS | <30 mcg/L | Suggests iron deficiency |
| JAMA 2025 | <30 ng/mL or TSAT <20% | Clinical diagnosis |
| BSG 2021 | <15 absent stores; <30 low stores; 45 best balance; >150 deficiency unlikely | Clinical decision-making in adults |
How inflammation affects ferritin
Ferritin rises during infection and in long-term inflammatory conditions such as IBD. A ferritin that looks normal may therefore hide iron deficiency, which is why WHO raises the threshold to 70 µg/L when inflammation is present. WHO also states that ferritin alone should not be used to diagnose iron overload.
What is the Mentzer index?
The Mentzer index is a simple calculation some doctors use when red cells are small: MCV (in fL) divided by RBC (in millions per µL). A result below 13 suggests thalassaemia trait; above 13 suggests iron deficiency (Mentzer, Lancet 1973).
| Example | MCV | RBC | Mentzer index | Suggests |
|---|---|---|---|---|
| Person A | 65 fL | 5.8 | 65 ÷ 5.8 = 11.2 | Thalassaemia trait more likely |
| Person B | 72 fL | 4.0 | 72 ÷ 4.0 = 18 | Iron deficiency more likely |
This is a hint only, not a diagnosis. Both conditions can exist together. Confirmation needs iron studies and haemoglobin electrophoresis (HbA2). Read thalassemia trait vs iron deficiency for the full picture.
Questions to ask your doctor
- Am I anemic, and how severe is it by WHO grading?
- Is my ferritin low, and is there any inflammation that could be affecting it?
- Are my red cells small, and should I be tested for thalassaemia trait?
- What is causing my low iron, and do I need further tests?
- Do I need treatment, which type, and when should I repeat the blood test?
If iron deficiency is confirmed, see our guides to iron deficiency anemia and how long iron supplements take to work.
Where Kabtafer Plus fits
Kabtafer Plus is an iron-free food supplement that supports absorption of iron from food. It is not a treatment for anemia and does not replace iron prescribed by your doctor. It is intended for people whose blood tests confirm low iron; if your ferritin is normal and you carry thalassaemia trait, it is not needed. Discuss your results with your doctor first. You can read the published studies.
Frequently asked questions
Can my haemoglobin be normal but my ferritin low?
Yes. Ferritin falls first, so low stores can be present well before haemoglobin drops below the anemia threshold.
What is a good ferritin level?
There is no single number for everyone. Clinical guidelines treat below 30 ng/mL as low, and the BSG notes that above 150 makes absolute iron deficiency unlikely. Your doctor will interpret yours.
Do I need to fast before an iron test?
Serum iron is affected by recent meals and supplements, so some labs prefer a morning sample. Follow the instructions your lab or clinic gives you.
My MCV is low. Does that mean I need iron?
Not necessarily. Low MCV can be due to thalassaemia trait, which does not respond to iron. Ferritin and, if needed, haemoglobin electrophoresis will clarify.
Why does my report show different reference ranges?
Each lab sets ranges for its own equipment and methods. Always use the ranges printed on your report.
Sources
- World Health Organization. Guideline on haemoglobin cutoffs to define anaemia in individuals and populations. 2024. who.int
- World Health Organization. WHO guideline on use of ferritin concentrations to assess iron status in individuals and populations. 2020. NCBI Bookshelf
- Auerbach M, DeLoughery TG, Tirnauer JS. Iron deficiency in adults: a review. JAMA 2025;333(20):1813–1823. PMID 40159291
- Snook J, et al. British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults. Gut 2021;70:2030–2051. gut.bmj.com
- NIH Office of Dietary Supplements. Iron: Fact Sheet for Health Professionals. ods.od.nih.gov
- StatPearls. Beta Thalassemia. StatPearls Publishing. NCBI Bookshelf
- Mentzer WC. Differentiation of iron deficiency from thalassaemia trait. Lancet 1973;1(7808):882.
This article is for general education and does not replace advice from your doctor or pharmacist.