Sysmex 2024 Fall Newsletter - Flipbook - Page 12
The Science of
Hematology
Anemia – basic facts and classi昀椀cation
Anemia is a global public health issue affecting an estimated one-third of the world’s population, with women
and young children being predominantly affected. According to the World Health Organization (WHO), anemia
is a condition in which the number of red blood cells (RBC) or the RBC’s capability of carrying oxygen is reduced,
resulting in an insuf昀椀cient oxygen supply to meet the individuals’ physiological demand. To diagnose anemia, the
hemoglobin (Hb) concentration is an effective screening tool. Appropriate Hb cutoffs were 昀椀rst published in 1968
by a WHO expert group and de昀椀ned anemia as < 13 g/dL for healthy males, < 12 g/dL for healthy females, and < 11
g/dL for pregnant women and children under 5 years.1 Accordingly, fertile women are a vulnerable group for the
potential development of anemia, along with children, elderly people and patients with chronic diseases.
Typical anemia symptoms include fatigue, shortness of breath, tachycardia and headache. These may be mild
but can lead to a serious reduction in the individual’s quality of life. In the long term, permanently insuf昀椀cient
oxygen supply caused by untreated anemia may seriously impair organ function. Therefore, detecting pre-anemic
conditions and diagnosing anemia in an early stage can facilitate a timely intervention to prevent irreversible
damage. The most common type of anemia is iron de昀椀ciency anemia (IDA). Other anemia types result from
vitamin de昀椀ciencies, blood loss events and infectious/chronic diseases. IDA can often be treated by nutritional iron
supplementation, while patients with hemolytic, aplastic or myelodysplastic anemia subtypes or anemia of chronic
disease (ACD) require precise differential diagnosis for adequate medical treatment to prevent the anemia from
becoming more severe.
The value of indices
Differential diagnosis usually requires a morphological classi昀椀cation of RBCs. This can often be achieved through
measurement of the RBC indices. Mean corpuscular volume (MCV), which re昀氀ects the average volume of red
blood cells in a sample, helps to distinguish between microcytic, normocytic and macrocytic anemia. Normal MCV
values range between approximately 80 and 100 fL. Impaired hemoglobin production, which is typical of IDA and
β-thalassemia, results in microcytic RBCs with MCV values < 80 fL. In contrast, MCV values > 100 fL are mainly
associated with abnormal erythropoiesis that may be seen in vitamin B12 and folate de昀椀ciencies or myelodysplasia.
Normocytic anemia, on the other hand, is characterized by normal MCV values and a reduced number of RBCs due
to acute bleeding, hemolysis and/or chronic diseases.
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