University of Virginia Health System

Nucleated Red Blood Cell
(NRBC)

Peripheral blood smear, Wright-Giemsa stain, 1000x

Description:

Usually they are orthochromatic, but earlier forms (polychromatophilic forms) may be seen. Small numbers of nucleated red blood cells normally are released from the bone marrow into the circulation, but are not seen on a peripheral blood smear if splenic function is normal or near normal. In otherwise normal asplenic individuals, nucleated red blood cells are seen on the peripheral blood smear along with a variable number of Howell-Jolly bodies, acanthocytes, Pappenheimer bodies, spherocytes, thrombocytosis, large granular (NK) lymphocytosis, monocytosis, and neutrophilia (usually transient).

Pathobiology:

Due to asplenia or hyposplenia in otherwise normal individuals. Also seen with disorders that disrupt bone marrow architecture (e.g. fibrosis, metastatic tumors), an increased rate of erythropoiesis (e.g. hemolytic anemia), and in megaloblastic and dyserythropoietic disorders.

Differential diagnosis:

• Asplenia and hyposplenia
• Hemolytic anemias
• Thalassemias
• Megaloblastic anemias
• Myelopthisic anemias with or without a leukoerythroblastic picture

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