Nucleated Red Blood Cells (Normoblasts)

Nucleated red blood cells, or normoblasts, are immature forms of red blood cells that contain a nucleus and are incapable of oxygen transport. Normally, normoblasts are absent in the peripheral blood of adults and children over one year old. Their presence in the blood of adults or children older than one year is a sign of a pathological process. Normoblasts develop in the bone marrow during erythropoiesis — the maturation process of red blood cells. Under normal conditions, they mature and lose their nucleus, transforming into reticulocytes and then into mature erythrocytes that circulate in the blood and supply oxygen to tissues.

Causes of normoblasts appearing in the blood:

• Hemolytic anemia and other forms of red blood cell destruction.
• Severe infections and inflammatory processes.
• Bone marrow diseases: myeloproliferative disorders, leukemias, myelofibrosis, myelodysplasia.
• Removal or dysfunction of the spleen (splenectomy).
• Acute blood loss and severe conditions causing increased erythropoiesis.
• Oncological diseases involving bone marrow damage.

The presence of normoblasts in the blood requires careful examination as it may indicate serious pathologies. Single normoblasts may occasionally be found in newborns (up to 1 year old) and pregnant women, which is considered physiological.

Clinical significance: Detection of normoblasts in the blood is a marker of active hematopoiesis and often indicates a compensatory response to hypoxia, blood loss, or red blood cell destruction. Significant elevation of normoblasts is associated with severe blood diseases and requires further in-depth investigation. Accurate diagnosis requires considering the clinical picture, results of other laboratory tests, and data from instrumental methods. Thus, the test for nucleated red blood cells helps detect and monitor a range of severe diseases, reflecting the bone marrow status and hematopoietic processes.