Automated Nucleated Red Blood Cell Enumeration Evaluated

The presence of peripheral blood nucleated red blood cell is associated with pathological conditions and leads to the overestimation of white blood cell count in automated hematology analyzers (HA) and therefore, accurate detection and enumeration of NRBCs are important.

Scientists at Mahidol University (Bangkok, Thailand) analyzed clinical blood specimens that were sent from both in- and out-patient departments to a central laboratory at during August 2013 and October 2013. These peripheral blood specimens were collected using dipotassium ethylenediaminetetraacetic acid (EDTA) as an anticoagulant. The residual samples from routine testing with adequate volume for repeated testing were used and were analyzed within two hours of blood collection.

The automated hematology analyzer used was the Sysmex XN-3000 (Sysmex Corporation; Kobe, Japan) which comprises one sampler, two Sysmex XN Modular analyzers, and one Sysmex SP-10 slidemaker/stainer. Blood smears were prepared on the Sysmex SP-10 slidemaker/stainer using Wright-Giemsa reagent. Staff member counted the number of NRBCs per 200 white blood cells (WBCs) using light microscope at × 400 magnification. Included in the study were 234 specimens from 127 patients (54 males and 73 females) with initial reports of NRBCs more than 0.1% by automated hematology analyzer.

In the comparison study between XN and MC, NRBCs ranged from 0% to 612.5%. Regression analysis demonstrated a close accord between the methods. The mean bias of 14.1% with 95% limits of agreement between 48.76% and 76.95% was found. The NRBC counts from XN appeared to be more in accordance with MC when the NRBCs were lower than 200% with the concordance rate of 94.2%.

The authors concluded that the automated NRBC enumeration by XN was precise and could replace the traditional MC, especially for the specimens with NRBCs lower than 200%. This approach may improve laboratory management, especially for laboratories which frequently encounter normoblastemia. It should be noted that MC is a very laborious procedure requiring skilled technical knowledge. The study was published in the June 2015 issue of the International Journal of Laboratory Hematology.

Related Links:
Mahidol University 
Sysmex Corporation