Nucleated RBCs (NRBCs) are immature RBCs not normally seen in the peripheral blood beyond the neonatal period. Their appearance in peripheral blood of children and adults signifies bone marrow damage or stress and potentially serious underlying disease. The presence of numerous NRBCs increases the WBC count in automated hematology analyzers. Most analyzers generate suspect flags to help identify abnormal cells, and the samples involved should be reviewed manually. Unfortunately, analyzers may not detect low levels of NRBCs. We recommend correcting the WBC count with even 1 NRBC/100 WBCs and reporting “occasional NRBC seen.” This alerts clinicians of the significance of unexplained normoblastemia.
Nucleated RBCs—Significance in the Peripheral Blood Film
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