Corrected White Blood Cell Counts

Nucleated red blood cells (nRBCs) are counted as white blood cells by our automated analyzers. For this reason, the “WBC” count from an analyzer or a hemocytometer is actually a nucleated count which includes WBC and nRBC. The obtained nucleated count must be corrected for the number of nRBC in the circulation if nRBCs are identified during the blood smear leukocyte differential. To correct the “WBC” or nucleated count, the number of nRBCs per 100 leukocytes is recorded during the differential leukocyte count when performing a blood smear examination. Then a correction is made as follows:

Corrected WBC = obtained nucleated cell count x [100 ÷ (nRBC + 100)]

This correction of the WBC count should be done any time 5 or more nRBCs are counted during the blood smear leukocyte differential count.

Ex: Automated WBC Count= 10,500/µL; nRBCs seen during differential count= 8

10,500 x [100 ÷ (8+ 100)] = 9,722/µL This is the corrected WBC count.