Performance Evaluation of Nucleated Red Blood Cell (Nrbc) Count Using a Fully Automated Haematology Analyzer Versus Manual Counting

Abstract

Objective: To evaluate the performance of Nucleated RBC (NRBC) Count using a fully automated haematology analyzer versus manual counting.
 Study Design: Cross-Sectional Study.
 Place and Duration of Study: Department of Hematology, Armed Forces Institute of Pathology, from Sep 2019-Jun 2020.
 Methodology: Routine fresh whole blood samples were run on Sysmex XN-3000 automated haematology analyzer and 384 samples with results of ≥0.1% Nucleated red blood cells were included in this study. Manual NRBC counting was carried out twice on Leishman-stained peripheral blood smears from all 384 samples. Comparison between manual and automated nucleated red blood cell counting methods was statistically analyzed through linear regression analysis & coefficient correlation. The degree of agreement between two methods was analyzed through Bland-Altman plot. Finally, concordance between the two methods was also analyzed at 5 different ranges of nucleated red blood cells.
 Results: Linear regression analysis revealed a (r2) value of 0.97. Regression equation was calculated as XN = 0.76MC ± 1.28, with 95% limits of agreement between ± 40.42% and -24.47%. A mean bias of 7.97% was demonstrated through Bland-Altman plot. Concordance analysis revealed a concordance rate of 93.74% (360/384). Nucleated red blood cell counting between two methods were more concordant when nucleated red blood cell counts were <200%.
 Conclusion: Nucleated red blood cells counting by XN-3000 automated hematology analyzer is statistically comparable to manual nucleated red blood cell counting. We suggest that automated counting can be adopted in routine hematology laboratory as a replacement of manual NRBC counting.

Correlation of nucleated red blood cell counts by Sysmex XN-1000 with conventional microscopy

“…They are preferable to manual count by being cost effective and convenient. Previous studies in other countries have been conducted to determine the precision and diagnostic accuracy of Sysmex XN series and they have been very encouraging [2,12]. Our study also shows that Sysmex XN-1000 analyzer with its WNR channel is highly sensitive (90.56%) and specific (88.30%) in enumerating nRBCs.…”

“…A previous study conducted in Pakistan showed that Sysmex analyzer measured nRBCs accurately up till 200 counts. Above that its measurement was not accurate [12]. This did not happen in our study.…”

“…It can also provide results that are easily reproducible and highly accurate. The implementation of automatic release of results by Sysmex will also allow to reduce turnaround time of CBC samples analysis of any laboratory [2,12]. It will also be helpful in hospital settings and laboratories in peripheral areas where the availability of trained hematologists is limited.…”

“…To lessen the manual review rate by using automated analyzer, we need to be certain that the analyzer detects nRBCs in all the samples and computes them accurately. Only one such study has been conducted in our population making it hard to permanently replace microscopy with automation [12]. Our study was designed to correlate the results of manual microscopy with that of Sysmex XN-1000 analyzers and determining its diagnostic accuracy, taking microscopy as gold standard.…”