The Mentzer index calculator is about distinguishing iron deficiency anaemia from beta-thalassemia. We get it from the results of a complete blood count. To answer the potential questions, the essay is provided below.

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What is thalassemia? Thalassemia vs. iron deficiency anemia.

The Thalassemia trait (TT) is a genetic disorder that causes lower haemoglobin levels. Haemoglobin (Hb) is a crucial protein molecule that enables red blood cells (RBCs) to carry oxygen.

Like Thalassemia, Iron deficiency anaemia (IDA) means that the value of the RBCs count is low, but because of the bone marrow, which cannot manufacture enough RBCs. Although their origin differs, the symptoms of both diagnoses are the same.

Thalassemia trait (TT) is a condition of genetic origins from either one or both parents. Two main types of TTs, alpha, and beta differ on the location of the mutation on genes. We can confirm the diagnosis with blood tests that reveal the number of RBCs and abnormalities in size, shape, or colour.

The only cure is stem cells or bone marrow transplants. People who have minor or mild forms of TT can lead everyday lives, but heart failure is possible in some cases. Nevertheless, other complications include abnormal skeletal growth, endocrine issues, and liver diseases.

Iron deficiency anaemia (IDA), a common type of anaemia, is a condition of lacking healthy red blood cells (RBCs), which carry oxygen to the body’s tissues. The main lead to IDA is due to insufficient iron. Most symptoms of IDA are due to anaemia. Such signs and symptoms include fatigue, loss of stamina, chest pain, weakness, dizziness, and shortness of breath. Accordingly, IDA can range from mild, with sometimes no signs or symptoms, to severe with worse symptoms as anaemia develops.

If left untreated, it can cause severe complications and even be life-threatening.

Iron deficiency anaemia treatment involves taking supplements enriched with iron for several months or even longer to replenish iron reserves.

Thalassemia MCV values

The mean corpuscular volume (MCV) measures the average red blood cell volume, the actual size of the cells themselves.

Mean corpuscular value, red blood cell distribution width (RDW), and the patient’s history excludes some of these etiologies. Usually, the MCV is less than 75 femtoliters (fl) with thalassemia and rarely less than 80 femtoliters (fl) in iron deficiency.

Normal MCV ranges are 80-96 femtoliters per cell.

A low MCV indicates that RBCs are small or microcytic, but a high MCV indicates larger than usual or macrocytic.

What is alpha thalassemia? What is beta thalassemia?

The thalassemias are a group of inherited disorders caused by defects in the synthesis of one or more haemoglobin chains. As mentioned above, Thalassemia Trait (TT) results from a mutation in a gene responsible for the production of globin. Two proteins form haemoglobin, alpha and beta.

The characteristics of alpha thalassemia are genetic defects in the alpha-globin gene, another known cause of mild microcytic anaemia, with features similar to beta-thalassemia. The main cause is an absent synthesis of alpha-globin chains that lead to an excess of beta-globin chains.

Beta thalassemia results from a deficient or absent synthesis of beta-globin chains. Beta globin chain production can range from near normal to completely absent, leading to varying degrees of excess alpha globin to beta-globin chain production.

When TT is “alpha” or “beta,” that refers to the missing part of haemoglobin. So, If either part is missing, there aren’t enough building blocks to make regular amounts of haemoglobin.

Low alpha is alpha-thalassemia, while low beta is beta-thalassemia.

Anemia consequences

Anaemia is a medical condition in which a patient lacks red blood cells (RBCs).

Health consequences of anaemia can include poor pregnancy outcomes, impaired physical and cognitive development, increased risk of morbidity in children, and reduced work productivity in adults.

Iron deficiency anaemia is an important public health problem in the Eastern Mediterranean Region.

It is caused by dietary deficiency – lack of iron, vitamin B12, or folic acid in diet malabsorption. Another cause can be thalassemia trait or sickle cell disease.

If not treated for an extended period, it can lead to heart failure, severe weakness, and poor immunity.

Mentzer index calculator and formula

The Mentzer index calculator is a beneficial asset in differentiating iron deficiency anaemia (IDA) from beta-thalassemia.  

It is based on a calculation of 2 values: the mean corpuscular volume (MCV), which is divided by the red blood cells (RBCs).

The Mentzer index equation is the following:

Mentzer \, index = \large\frac{MCV }{RBC}

Differentiation between thalassemia trait (TT) and iron deficiency anaemia (IDA) depends on whether the result is lower or higher than the value of 13. If the result is <13, thalassemia is more probable, but if the result is >13, iron deficiency anaemia is the most probable.

Mentzer index more than 13

If the Mentzer index value is above 13, iron deficiency anaemia is the most probable diagnosis.


What is the normal range of thalassemia?

Thalassemia major is characterized by reduced Hb level (<7 g/dl), mean corpuscular volume (MCV) > 50 < 70 fl and mean corpuscular Hb (MCH) > 12 < 20 pg.
Thalassemia intermedia is characterized by Hb level between 7 and 10 g/dl, MCV between 50 and 80 fl, while MCH is between 16 and 24 pg.

How accurate is the Mentzer index?

Diagnostic test analysis revealed a sensitivity of 93%, specificity of 84%, and accuracy of 90%.
The Mentzer index has good validity as a simple and inexpensive screen for IDA in 6-12-year-old children with hypochromic-microcytic anaemia.

What is the normal Mentzer index?

Calculation of the Mentzer index (mean corpuscular volume per red cell count) may be helpful. For instance, a Mentzer index of less than 13 suggests that the patient has the thalassemia trait (TT). Conversely, an index of more than 13 suggests that the patient has iron-deficiency anaemia (IDA). So, accordingly, the normal Mentzer index value is 13.

How do you calculate the Mentzer index?

The Mentzer index is calculated from the results of a complete blood count.
The mean corpuscular volume (MCV) quotient is divided by the red blood cell count (RBC).