Anemia, the false beliefs that cost us our health. (Part One)

What is Anemia?

Anemia is the most common hematologic disease. Traditionally, the clinical significance of anemia has been underestimated (no pain, but fatigue as the main symptom, which is not very specific and sharp as pain). In our medical practice, anemia is undervalued, misdiagnosed, mistreated.

Identifying the cause of anemia is more important than even treating the anemia itself (the cause of anemia could be a malignant disease). Similarly, not treating anemia has consequences for healthcare costs and reduced work productivity. Therefore, anemia should be properly evaluated and treated by doctors, and if not possible, refer to a hematologist.

Although from a pathophysiological perspective, anemia is defined as a decrease in the total mass of circulating erythrocytes, functionally it is defined as a decrease in the blood's oxygen-carrying capacity resulting in tissue hypoxia. The primary function of blood, its identification, is the transport of oxygen.

All cells depend on oxygen to live, different degrees of anemia will have different levels of cellular hypo-oxygenation and clinical consequences, which will be determined by the speed of anemia onset, its degree, the patient's age, and the hemoglobin dissociation curve from oxygen, as we will see below.

The term "anemia" used in clinical medicine refers to the reduction below the accepted normal values of hemoglobin (according to the person's age and gender) with or without a decrease in the absolute number of erythrocytes. The reduction in hemoglobin leads to the appearance of symptoms and signs of anemia.

In daily practice, for the evaluation of anemia, besides hemoglobin concentration, Red Blood Cell Count (RBC) and Hematocrit Value (Hct) are used. Hematocrit assesses the ratio of erythrocytes compared to plasma (the liquid environment in which they are found).

Thus, when evaluating anemia, the plasma volume should also be evaluated, whether it is increased resulting in dilution of blood's formed elements or it is decreased resulting in a non-real increase in the number of formed elements in the blood. In these cases, evaluation should be done after correcting the plasma volume. A number of important factors influence the normal values of these three parameters, such as: gender, age, race, altitude of the living place.

The diameter of erythrocytes is 6-8 mm (average 7.5 mm). Erythrocytes with normal sizes are called normocytes, erythrocytes with sizes < 6 micrometers are called microcytes (small cells), erythrocytes with sizes > 9 micrometers are called macrocytes (large), erythrocytes with sizes > 12 micrometers are called megalocytes (very large).

Regarding color, erythrocytes are normochromic (normal color), hypochromic (with reduced color), but not hyperchromic as a normochromic erythrocyte means that it is filled to its maximum capacity for its size.

Due to the large number of erythrocytes produced every day by the bone marrow, many precursors are required for the production of new cells and large amounts of hemoglobin. These substances are:

1. Metals: iron, manganese, and cobalt.
2. Vitamins: Vitamin B12, Folic Acid, Vitamin B6, Vitamin C, Vitamin B1, Vitamin B2, Vitamin E.
3. Amino acids.
4. Regulatory substances: Erythropoietin, growth factors, androgens, glucocorticoids, Thyroxine.

Some data on the red series in adults (Erythrocyte Series)

1. Hemoglobin (gr/dl): 13.0-17.5 (males) and 12-15.5 (females)
2. Number of erythrocytes (RBC, in million/mm3): 4.5-6.5 (males) and 4-5.6 (females)
3. Hematocrit (Hct or PCV in %): 42-52 (males) and 35-45 (females)
4. Reticulocytes, the normal value is 0-20 ‰ or 0-2 %

Rule of Three

There is a relationship between the number of erythrocytes, hemoglobin values, and hematocrit for normochromic, normocytic erythrocytes. All three values follow the rule of three:

• The hemoglobin value is the multiplication of the first number of erythrocytes by 3.
• The hematocrit value is the multiplication of the hemoglobin value by 3.

Example: Erythrocytes 5,000,000 mm3 = 15 gr/dl hemoglobin (5.0 x 3) = 45 % hematocrit (15 x 3).

Erythrocyte constants (calculated or derived from peripheral blood analysis done with a machine) MCV, MCH, MCHC were first described by Wintrobe in 1929 to assess the sizes (MCV) and hemoglobin content (MCH, MCHC) in erythrocytes. In a peripheral blood analysis done on automatic machines will be evaluated:

1. Mean Corpuscular Volume (MCV) assesses the sizes of an "average" erythrocyte in the analysis obtained. The normal value is 87 ± 7 fl. In these cases, we talk about normocytosis, less about microcytosis, more about macrocytosis and megalocytosis.
2. Mean Corpuscular Hemoglobin (MCH) assesses the absolute amount of hemoglobin for an "average" erythrocyte. The normal value is 29 ± 2 picograms (pg) per erythrocyte. In these cases, we talk about normochromia and below this value about hypochromia.
3. Mean Corpuscular Hemoglobin Concentration (MCHC) assesses the average amount of hemoglobin per cell. Unlike MCH, MCHC correlates the hemoglobin content with the cell volume. The normal values are 34 ± 2 g/dl. In these cases, we talk about normochromia and below this value about hypochromia.
4. RDW (Red Cell Distribution Width) assesses erythrocyte anisocytosis, i.e., variation in the sizes of erythrocytes in the population under study and is expressed as a percentage. The normal values are 13 ± 1.5%. RDW becomes abnormal (increases) in iron deficiency anemia faster than all other blood cell parameters. Increased RDW suggests early nutritional deficit, especially for iron. An increased RDW is the first indicator of iron deficiency.
5. Color Index (CI) - assesses the degree of erythrocyte saturation with hemoglobin and is calculated using the ratio between the hemoglobin value / the number of erythrocytes multiplied by three. The norm is 0.9-1.1 (normochromia) and less than 0.9 we talk about hypochromia.