Mentzer Index Calculator

Distinguish between thalassemia and iron deficiency anemia using MCV and RBC values

Calculate Mentzer Index

fl

Normal range: 80-95 fl (femtoliters)

million/mm³

Normal range: 4.5-5.9 million/mm³ (men), 4.1-5.1 million/mm³ (women)

Mentzer Index Results

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Mentzer Index

Formula used: Mentzer Index = MCV ÷ RBC

Interpretation: <13 suggests thalassemia, >13 suggests iron deficiency

Medical Disclaimer: This calculator is for educational purposes only and should not replace professional medical diagnosis. Always consult with a healthcare provider for proper evaluation and treatment.

Index Analysis

< 13
Thalassemia likely
= 13
Inconclusive
> 13
Iron deficiency likely

Example Calculations

Thalassemia Example

MCV: 62 fl

RBC: 5.2 million/mm³

Index: 62 ÷ 5.2 = 11.9

Result: <13 → Thalassemia likely

Iron Deficiency Example

MCV: 68 fl

RBC: 3.8 million/mm³

Index: 68 ÷ 3.8 = 17.9

Result: >13 → Iron deficiency likely

Thalassemia vs Iron Deficiency

Thalassemia

  • • Genetic disorder
  • • Normal RBC count
  • • Small, fragile RBCs
  • • Mentzer Index <13

Iron Deficiency

  • • Nutritional/blood loss
  • • Reduced RBC count
  • • Small RBCs
  • • Mentzer Index >13

Normal Ranges

MCV (Mean Corpuscular Volume)

Adults: 80-95 fl

Newborns: 96-108 fl

RBC Count

Men: 4.5-5.9 million/mm³

Women: 4.1-5.1 million/mm³

Hemoglobin

Men: 14-18 g/dL

Women: 12-16 g/dL

Understanding the Mentzer Index

What is the Mentzer Index?

The Mentzer Index is a simple screening tool used to differentiate between two common causes of microcytic anemia: thalassemia and iron deficiency anemia. It uses readily available laboratory values from a complete blood count (CBC).

Clinical Significance

  • Helps distinguish between inherited vs acquired anemia
  • Guides further diagnostic testing
  • Cost-effective screening method
  • Widely available in clinical settings

Formula and Interpretation

Mentzer Index = MCV ÷ RBC

  • MCV: Mean Corpuscular Volume (femtoliters)
  • RBC: Red Blood Cell Count (million/mm³)
  • < 13: Thalassemia more likely
  • > 13: Iron deficiency more likely
  • = 13: Inconclusive result

Important: The Mentzer Index is a screening tool, not a definitive diagnostic test. Further testing is always required for confirmation.

Understanding Thalassemia

Thalassemia is an inherited blood disorder caused by genetic mutations affecting hemoglobin production. The body produces normal numbers of red blood cells, but they are smaller and more fragile than normal.

  • Alpha Thalassemia: Affects alpha globin chains
  • Beta Thalassemia: Affects beta globin chains
  • Thalassemia Major: Severe form requiring treatment
  • Thalassemia Minor: Mild form, often asymptomatic

Understanding Iron Deficiency Anemia

Iron deficiency anemia occurs when the body lacks sufficient iron to produce healthy red blood cells. This results in both fewer and smaller red blood cells being produced.

  • Common causes: Blood loss, poor diet, pregnancy
  • Symptoms: Fatigue, weakness, pale skin
  • Treatment: Iron supplementation, dietary changes
  • Prognosis: Excellent with proper treatment