Nucleated red blood cells are often reported in percent (number per 100 leukocytes). This may be hard to interpret since any change may reflect a change in the WBC count. Calculating the absolute nucleated red blood cell count is more useful.



(1) percent NRBCs per 100 leukocytes

(2) WBC count


absolute NRBC count =

= (percent) * (WBC count)



• According to Green and Mimount the 90th percentile for the absolute NRBC count in normal neonates was 1,000 per µL (1 * 10^9/L).

• Nucleated red blood cells are not normally seen in the peripheral blood in older infants, children or adults.


Alternatively, the difference between a direct automated leukocyte count and the leukocyte count after adjustment for NRBCs (see above) should reflect the absolute NRBC count.


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