Comparison between Nageotte and flow cytometric counting of residual leucocytes in freshly prepared leucocyte-reduced red blood cell components. Issue 4 (August 2018)

• Record Type: Journal Article
• Authors: Kyriakou, Elias; Nearchakos, Nikolaos; Bonovas, Stefanos; Makri, Efstathia; Pantavou, Katerina; Nikolopoulos, Georgios K.; Kottaridi, Christine; Gialeraki, Argyri; Douramani, Panagiota; Taichert, Maria; Kapsimali, Violetta; Tsantes, Argirios E.
• Is Part Of: Transfusion and apheresis science. Volume 57:Issue 4(2018)
• Page Start: 544
• Page End: 548
• Publication Date: 2018-08
• Subjects: Leukoreduction -- Nageotte -- Flow cytometry -- Leucocyte counting -- Red blood cell unit; Blood -- Transfusion -- Periodicals; Hemapheresis -- Periodicals; 615.39
• DOI: 10.1016/j.transci.2018.06.002
• Languages: English
• ISSNs: 1473-0502

Abstract

Abstract: Background: Flow cytometry (FC) and Nageotte hemocytometry represent the most widely accepted methods for counting residual white blood cells (rWBCs) in leucocyte-reduced (LR) blood components. Our aim was to study the agreement between the two methods, under real working blood bank conditions. Materials and methods: 94 freshly produced LR red blood cell (RBC) units were tested for rWBC concentrations by FC and Nageotte. To assess the precision of each method, we calculated the intra-assay coefficients of variation (CV), and followed the Bland-Altman methodology to study the agreement between the two methods. Results: CV was 18.5% and 26.2% for the Nageotte and the FC, respectively. However, the agreement between the duplicate observations, using the binary cut-off threshold of 1 × 10 6 WBCs per unit to define the results as "pass/fail", was 71.9% for the Nageotte and 93.3% for the FC. Linear regression analysis did not show any correlation (R-squared = 0.01, p = 0.35) between the two methods, while the Bland-Altman analysis for the measuring agreement showed a bias toward a higher Nageotte count of 0.77 × 10 6 leucocytes per unit (p < 0.001) with the 95% limits of agreement (d ± 2 sd) ranging from –0.40 × 10 6 to 1.94 × 10 6 leucocytes per unit. Conclusion: The absence of agreement between Nageotte and FC method, with the differences within d ± 2 sd being of high clinical importance, suggests that the two methods cannot be used for clinical purposes interchangeably. The Nageotte seems unsuitable for quality control even with a pass-fail criterion, under real working blood bank conditions.