Why anemia can never be hyperchromic

Classifications (classifications) of anemia

Author: Prof. Dr. Stefan Eber, Ingrid Grüneberg, created on: 02/01/2017, editing: Ingrid Grüneberg, approval: Prof. Dr. Ursula Creutzig, last changed: April 24, 2019

Classification of Anemia - Introduction

To find out what the cause of anemia is, or at least to narrow it down, is the Determination of the size of a red blood cell helpful. Certain laboratory values, the so-called Red cell indices MCV, MCH and MCHC, are used for this. The average size (volume) of a blood cell is expressed as MCV (Mean Corpuscular Volume), the mean cell volume. Normal ranges (reference intervals) are defined depending on the age and gender of the patient. In anemia, these cell volumes can be too small or too large compared to the normal range, but they can also be of normal size. For further clarification, laboratory values ​​for the content (hemoglobin value MCH) and the concentration (MCHC) of the red blood pigment are used.
Another way of subdividing anemia is the type of Disorders in the formation of red blood cells as well as theirs Dismantling (Hemolysis). Anemias are also assessed in terms of whether or not they congenital or acquired are divided.


English name

German name



mean cell volume

mean volume of a single erythrocyte



mean corpuscular hemoglobin

mean hemoglobin content of a single erythrocyte

pg / cell


mean corpuscular hemoglobin concentration

mean hemoglobin concentration of a single erythrocyte

g / dl

Classification according to the size of the red blood cells

Red blood cells that are too small - microcytic anemia

Laboratory values ​​MCV (volume) and MCH (hemoglobin content) are reduced.
Red blood cells that are too small in an iron deficiency patient. Because of the iron deficiency, the cells have too little hemoglobin (red blood pigment). The blood cells are only faintly colored or ring-shaped.

Microcytic hypochromic anemias (hypochromic - weak intensity of the red color) are typical in:

Blood cells that are too large - macrocytic anemia

Laboratory values ​​MCV (volume) and MCH (hemoglobin content) are increased
Normally sized on the left, a red blood cell that is too large, a so-called megalocyte, on the right.

Macrocytic hyperchromic anemia (hyperchromic - increased intensity of the red color) can be caused by:

Normally sized blood cells - normocytic anemia

Laboratory values ​​MCV (volume) and MCH (hemoglobin content) are normal
Normally sized red blood cells with normal levels of red blood pigment.

Normocytic, normochromic anemias (normochromic - normal intensity of the red color) occur in:

  • Bleeding (loss of red blood cells)
  • Haemolysis (increased breakdown of red blood cells)
  • Aplastic anemia
  • Renal anemia (anemia due to acute or chronic kidney disease)

Classification according to the cause

Another subdivision of anemia is made according to specific functional disorders of the red blood cells.
Each blood cell is made in the bone marrow and then enters the bloodstream. After a certain lifespan, the individual blood cells are broken down again. During this process, disturbances in blood formation and blood breakdown (haemolysis) can occur. Heavy bleeding can also lead to anemia.

Educational disorders in red blood cells

Disturbances in the formation of red blood cells (erythrocytes) can have different causes. A bone marrow disease can lead to a marked reduction in the blood-forming stem cells, as in aplastic anemia. There may also be deficiencies in substances that are necessary for the formation of red blood cells or the red blood pigment. These include an iron deficiency or deficiency in vitamin B12. Chronic kidney disease or malfunctioning kidneys are deficient in the growth factor erythropoietin. Erythropoietin is mainly produced in the kidney. The following anemias are included:

Increased breakdown of red blood cells (hemolysis)

Corpuscular hemolytic anemia
The cause of the increased breakdown of red blood cells lies at the erythrocytes themselves. These include defects in the cell membrane of the red blood cells or certain disorders in individual blood components. In hemoglobinopathies, there are defects in the red dye. The corpuscular anemias are mostly congenital. These include:

Extracorpuscular hemolytic anemia
The cause of the increased breakdown of red blood cells lies outside of erythrocytes. Autoimmune diseases as well as viral infections or certain drugs can lead to haemolysis. Such a form of anemia is:

Autoimmune Hemolytic Anemia

Bleeding (loss of red blood cells)

Acute or chronic blood loss can mean that the loss of erythrocytes is greater than their formation. Acute severe bleeding can result from injuries or operations. Chronic blood loss occurs with stomach ulcers or heavy menstrual bleeding.

Classification according to congenital or acquired anemia

Congenital forms

In the congenital forms of anemia, there are usually pathological changes in genes that play an important role in blood formation. Such genetic defects often occur in connection with certain hereditary diseases. The most common congenital form of anemia worldwide, which is associated with other health problems in children and adolescents, is sickle cell disease. Congenital anemias are:

Diamond-Blackfan anemia
Dyserythropoietic anemia
Fanconi anemia
Ball cell anemia
Sickle cell disease

Acquired forms

In the acquired forms, the deficiency of certain vitamins such as vitamin B12, Blood loss, severe kidney disease, an underactive thyroid, some pathogens, some drugs or even malignant diseases lead to disorders of blood formation in the course of life and thus cause anemia.
The most common acquired form of anemia in children and adolescents worldwide is iron deficiency anemia. Acquired anemias are:

Chronic Disease Anemia
Autoimmune Hemolytic Anemia
Iron deficiency anemia

Comprehensive study of blood values ​​in children and adolescents

in Germany, results from 2016 here

Guideline for anemia diagnostics in childhood

This guideline, written for physicians, provides further information on diagnosing childhood anemia. To the guideline